Slide 1

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 2

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 3

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 4

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 5

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 6

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 7

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 8

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 9

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 10

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 11

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 12

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 13

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 14

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 15

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 16

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 17

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 18

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 19

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 20

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 21

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 22

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 23

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 24

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 25

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 26

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 27

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 28

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 29

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 30

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 31

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 32

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 33

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 34

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 35

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 36

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 37

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 38

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 39

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 40

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 41

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 42

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 43

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 44

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 45

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 46

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 47

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 48

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 49

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 50

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 51

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 52

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 53

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 54

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 55

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 56

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 57

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 58

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 59

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 60

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 61

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 62

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 63

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 64

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 65

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 66

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 67

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 68

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 69

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 70

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 71

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 72

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 73

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 74

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 75

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 76

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77


Slide 77

INTRODUCTION TO HUMAN
NUTRITION
1219
Steven C Seideman
Extension Food Processing Specialist
Cooperative Extension Service
University of Arkansas

1

OBESITY RANKED #2
HEALTH ISSUE
• Obesity has recently been ranked the #2 health
problem in the U.S. behind cigarette smoking.
• Obesity in itself is not a problem but causes
several secondary problems including diabetes,
hypertension (high blood pressure), and others.
• Obesity is a result of excessive caloric intake and
the lack of physical exercise.

2

3

Human Nutrition
• Human nutrition is the study of how food
effects the health and survival of the human
body.
• We need food to supply the human body for
functions such as growth, maintenance and
reproduction.
• Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals and water.
4

DIGESTION

5

Overview of the Digestive
Process
• All foods contain nutrients, and nutrients
are released from food through the process
called “digestion”.
• Let’s go through the steps of the digestive
process.

6

DIGESTION
• The first steps of digestion occur when we
put food in our mouth.
• Chewing is a mechanical action that breaks
food down to smaller particles.
• The saliva in our mouths contains enzymes
(proteins that break down foods) that
chemically reduce the food to smaller
particles.
7

DIGESTION
• After food is chewed, it goes to the stomach.
• Acids and enzymes in the stomach break the food
down into even smaller particles.
• Food then goes through the intestines and is
moved along by muscle contractions.
• Nutrients are absorbed from the inside of the small
intestine into the bloodstream and carried to the
sites in the body where they are needed.
8

DIGESTION
• The parts of the food that are not absorbed
continue to move down the intestinal tract
and are eliminated from the body as feces.

9

COMPONENTS OF FOOD

10

COMPONENTS OF FOODS
• Foods are essentially made up of water,
carbohydrates, proteins, fats, vitamins and
minerals.
• The most abundant component of food is
water, often as high as 75- 95%.
• Vitamins and minerals make up the least
abundant components of food, often in the
range of 1-4%.
11

COMPONENTS OF FOODS
• Carbohydrates – These are short and long
branches of glucose molecules. Shorter
molecules such as sugars and starches are
readily digested and utilized. Longer and
branched chain molecules, called
hemicellulose and cellulose, often referred
to as “fiber” are not useable as a nutrient
source.
12

COMPONENTS OF FOOD
• Proteins- Proteins are made up of long
chains of amino acids. Some proteins are
highly digestible while others are not. The
action of acids and enzymes in the stomach
break down most proteins into amino acids
that can be adsorbed in the intestinal wall.

13

COMPONENTS OF FOOD
• Fats – Fats and oils are very similar in
structure, however, oils contain more double
bonds and are often referred to as
unsaturated or polyunsaturated. Fats/oils are
chemically altered (esterified) in the
stomach by bile which makes them more
readily absorbable in the small intestine.
14

TYPES OF FOODS
Foods are generally high in some components and
low in others.
• Milk – Very high in water, 3.5% protein,
3.5% fat
• Cheeses- High in protein and fat
• Cereals (Bread, crackers, etc.)- High in
carbohydrates
• Beverages- very high in water
• Meats- High in protein and fat
• Fruits and Vegetables- High in water and
carbohydrates

15

COMPOSITION OF FOODS
COMPONENT

% Water

Milk
Beef
Chicken
Fish
Cheese
Cereal grains
Potatoes
Carrots
Lettuce
Apple
Melon

87.3
60.0
66.0
81.8
37.0
10-14
78.0
88.6
94.8
84.0
92.8

%Carbohydrates
5.0
0
0
0
2.0
58-72
18.9
9.1
2.8
15.0
6.0

%Protein % Fat % Min/Vit
3.5
17..5
20.2
16.4
25.0
8-13
2.0
1.1
1.3
0.3
0.6

3.5
22.0
12.6
0.5
31.0
2-5
0.1
0.2
0.2
0.4
0.2

0.7
0.9
1.0
1..3
5.0
0.5-3.0
1.0
1.0
0.9
0.3
0.4
16

CALORIES

17

CALORIES
• Food components can be classified by their
energy value or “calorie content”.
• A “calorie” is the amount of energy or heat
required to raise the temperature of one
gram of water one degree Celsius.
• The kilocalorie (1,000 calories) is the unit
commonly used in expressing energy values
of foods.
18

CALORIES
• The total energy of foods is determined by
burning the food in a steel bomb
calorimeter.
• Food is burned in the bomb calorimeter, and
the rise in water temperature is measured,
which is the total potential energy value of
the food.
19

CALORIES
• The total potential energy of a food as
determined by a bomb calorimeter may not
be equal to the energy that may be derived
from it by a human. If a food is not totally
digestible, acidified in the stomach or
absorbed by the small intestine, or it is not
totally oxidized within the body, then its
caloric value will be less than its theoretical
total energy content.
20

CALORIES
• On average, the following components of
food yield the following potential energy
values;
• Carbohydrates = 4.0 kcal/gram
• Proteins = 4.0 kcal/gram
• Fats = 9.5 kcal / gram
• These figures permit approximate
calculations of the energy values of foods.
21

CALORIES
• The previous values were determined by a bomb
calorimeter which is not exactly the same as
human digestion and utilization;
• For example, carbohydrates- The values hold true
for sugars and starches, but cellulose is potential
energy is not utilizable by humans.
• Similar situations also hold true for proteins and
fats.
22

CALORIES
• The body needs calories for production of heat,
synthesis of body tissues and performance of
work.
• Even the heart that beats all day and night uses
energy.
• In a broad sense, nutrients are needed for
maintenance (body heat, heart beat,etc.), growth
(we are constantly rebuilding body tissues) and
reproduction.
23

CALORIES
• The amount of energy /calories you require varies
greatly depending upon such factors as;
• Physical Activity- Someone that physically labors
all day will require far more calories than an office
worker.
• Climatic Condition- cold temperatures require
more energy to keep the body warm.
• Weight – more weight equals more work to move.
• Age- calorie utilization decreases as we increase in
age
• Sex- females may require additional energy if
pregnant
• Individual metabolic differences – efficient feed 24
converters.

CALORIES
• Daily requirements typically 2,000 kcal per day
except real young and real old.
• Fats are the most concentrated source of food
calories; carbohydrates are the cheapest source,
and proteins are the most expensive.
• In much of the world, people go hungry, but in
the US and certain other countries, obesity from
excess caloric intake is a major nutritional disease.
25

BIOLOGICAL
PRIORITIZATION

26

BIOLOGICAL
PRIORITIZATION
• Nature has a way of prioritizing the order in
which we use energy.
• If we take the total supply of energy
digested and utilized by the body, it goes to
various tissues and locations in a way to
preserve life.

27

Body Functions
Total Supply of Energy

=

Body Tissues
Body Locations

Fat Depots

28

Biological Prioritization
• Body Functions
1) Maintenance- heat, heartbeat, digestion,
physical activity
2) Growth
3) Reproduction
Once these activities are all satisfied, excess
energy goes to fat.
29

Biological Prioritization
• Body Tissues- those most needed for life
1)Nervous tissues
2)Skeletal tissues
3)Muscle
4)Fat

30

Biological Prioritization
• Body Locations- most needed to sustain life
1) Head
2) Neck and shoulder
3) Hind limb
4) Mid section (back)

31

Biological Prioritization
• Fat Depots
1) Kidney
2) Intermuscular
3) Subcutaneous
4) Intramuscular

32

Biological Prioritization
• Energy sources are used in this order;
• CARBOHYDRATES
1) Blood Glucose
2) Muscle Glycogen
• FATS
• PROTEINS
33

METABOLISM

34

METABOLISM
• Once food is digested, absorbed through the small
intestine and carried throughout the body via the
bloodstream, it now needs to be utilized by the
ultimate tissue such as muscle or skin cells.
• Once a nutrient is inside a tissue, whether it be
muscle or skin cells, the basic metabolism is all
very similar.
• Almost all tissues carry out the same functions
such as glycolysis and the Kreb’s Cycle.
Carbohydrates, Proteins and Fats are all interconvertible inside tissues.
35

36

37

METABOLISM
• It is important to mention again that all
carbohydrates, protein and fats are interrelated and
inter-convertible to energy.
• This means that you can eat a diet high in protein
and still have excess calories beyond your needs to
store as fat. Excess carbohydrates are also stored
as fat.
• This also means that cells have the ability to interconvert carbohydrates to fat and fat to protein, etc.
38

METABOLISM
• The fact that carbohydrates, fats and proteins are
inter-convertible shows the amazing ability of the
body to live through periods of malnourishment; it
is not recommended as a practice.
• The body has need of certain amino acids
(building blocks of protein) and some fatty acids
(fats) that cannot be made in the body and must be
supplied by certain foods.
• Some vitamins such as A, D, E and K are fat
soluble and are to be found associated with the
fatty fractions of natural foods.
39

VITAMINS

40

Vitamins
• Vitamins are organic chemicals that must be
supplied to the body in small amounts to
maintain health.
• Vitamins function in enzyme systems which
facilitate the metabolism of proteins,
carbohydrates and fats.
• Vitamins are characterized as either fat
soluble (A,D, E and K) or water soluble.
41

FAT SOLUBLE VITAMINS
(Vitamins A,D, E and K)

42

FAT SOLUBLE VITAMINS
• Vitamin A- occurs only in animal materials
such as meat, milk, eggs, etc. Plant material
contains no vitamin A but has its precursor,
B-carotene that can be converted in the cell
to vitamin A.
• Vitamin A deficiency can lead to blindness,
poor bone and tooth development, and can
decrease the body’s resistance to disease.
43

FAT SOLUBLE VITAMINS
• Vitamin D – is formed in the skin of
humans by activation of sterols (cholesterol
and ergosterol) and by ultraviolet light from
the sun.
• Shortage of vitamin D results in bone
defects, the principle one being rickets.
• Most milk is now fortified with ergosterol
from yeasts as a source of vitamin D.
44

VITAMIN E
• Vitamin E is also known as alpha-tocopherol.
• Although claimed to do a lot of things from
preventing diseases, prolonging youth and
increasing sexual potency, there is little scientific
data to support these claims.
• Vitamin E is a strong antioxidant and plays a role
in iron absorption. Since deficiencies of vitamin E
are rare, it is hard to study its importance to
nutrition.
45

VITAMIN K
• Vitamin K is essential for normal blood
clotting.
• Vitamin K deficiency generally parallels
liver disease where fat absorption is
abnormal.

46

THE WATER SOLUBLE
VITAMINS
Vitamins C, Thiamin B1,
Riboflavin B2, Niacin, B6,
Pantothenic Acid, B12,and Folic
acid

47

Vitamin C
• Vitamin C, also known as ascorbic acid, prevents
scurvy – a disease sailors (limies) used to get from
not having fruit for long periods of time.
• Vitamin C deficiency causes fragile capillary walls
(easy bruising), easy bleeding of gums, loosening
of teeth and bone joint diseases.
• Vitamin C is readily found in citrus fruit,
tomatoes, cabbage and green peppers.
48

VITAMINS OF THE B
COMPLEX GROUP
• All members of the vitamin B complex
generally are found in the same principle
food sources, such as liver, yeast and the
bran of cereal grains. All are required for
essential metabolic activities, and several
function as parts of active enzymes.
Absence of a particular B vitamin results in
a specific deficiency disease.
49

THIAMIN ( Vitamin B1)
• A deficiency of vitamin B1 results in
“beriberi”.
• The deficiency is common where polished
rice (bran has been removed) is a major
dietary item.
• Most wheat breads are now fortified with
thiamin.
50

RIBOFLAVIN (Vitamin B2)
• Riboflavin functions in the oxidative
processes of living cells and is essential for
cellular growth and tissue maintenance.
• Deficiency in humans generally results in
skin conditions such as cracking at the
corners of the mouth.
• Milk, liver and eggs are excellent sources.
51

NIACIN (Nicotinic acid)
• Niacin should not be confused with nicotine in
tobacco products.
• Deficiency of niacin adversely affects tissue
respiration and oxidation of glucose and results in
a disease known as pellagra or black tongue, once
common in Southeastern U.S.
• Deficiency is characterized by skin and mucous
membrane disorders as well as depression and
confusion.
• Most breads are now fortified with niacin.
52

Vitamin B6
• Vitamin B6 is essential in the human diet
for specific enzyme systems and normal
metabolism.
• A deficiency of this vitamin does not cause
a well-recognized disease.
• Vitamin B6 is widely distributed in foods.

53

PANTOTHENIC ACID
• Because pantothenic acid is widespread in
foods, there appears to be no deficiency
problems in humans.

54

VITAMIN B12
• Vitamin B12 is important in nucleic acid
formation and in fat and carbohydrate metabolism.
• It is often referred to as the anti-pernicious anemia
factor. Strict vegetarians may not get enough B12
in their diet, since it is virtually absent in plant
tissue, and they may suffer from pernicious
anemia.
• Good sources include liver, meat and seafoods.
• Vitamin B12 has recently been implicated in
memory function especially in the elderly where
meat is restricted.
55

FOLACIN
• Folacin and folate are names of chemicals
exhibiting the vitamin activity of folic acid.
• Folic acid, like B12, prevents certain kinds
of anemias and is involved in the synthesis
of nucleic acids.

56

MINERALS

57

MINERALS
• Minerals, like vitamins, are needed for
normal metabolism. They are generally
required in very small amounts, but the lack
of certain ones can lead to severe
consequences.

58

ESSENTIAL MINERALS
•
•
•
•
•
•
•
•

Calcium
Phosphorus
Magnesium
Iron
Copper
Cobalt
Zinc
Sodium

•
•
•
•
•
•
•

Chloride
Potassium
Iodine
Fluorine
Manganese
Chromium
Molybdenum
59

Dietary Guidelines

60

Dietary Guidelines
•
•
•
•

Avoidance of overweight
Consumption of a variety of foods
Reduction of total fat to less than 30% of calories
Reduction in the amount of saturated fats and
cholesterol consumed.
• Moderation in the consumption of salt and
alcohol.
• Increased consumption of fresh fruits and
vegetables and other fiber-containing foods.
61

62

NUTRITION
• Eat from all food groups each day.
• Obesity in the U.S. is caused primarily by
overeating. Understand what portion size is.
• Fat, carbohydrates and protein are all
interconvertable via Krebs cycle.
• Atwater Factor; Carbohydrates=4.5, Proteins=4.5;
Fat =9.0. Calories per gram.
• Nutritionally better off today. Few cases of goiter,
rickets, pellagra, kwashiorkor, scurvy.
63

Caloric Intake
• Current Calories in the U.S. diet come from
carbohydrates ( 46%), fat (42%) and protein
(12%).
• It is recommended that the caloric intake should
be from carbohydrates (45-65%), fat ( 20-35%)
and protein (12%).
• This means we should increase our percentage of
calories from carbohydrates and reduce the
percentage of calories from fat.
64

Diets
• There are lots of diet plans, and all may
work to some extent. The bottom line to
losing weight is decreased caloric intake
and increased physical activity.

65

Dr Adkins High Protein Diet
• The Adkins high protein diet stresses the
reduction in calories from carbohydrates
and increased consumption of protein.
• This diet plan has worked for millions of
Americans, however, there are concerns
within the scientific community of its
consequences over an extended period of
time.
66

Dr Phil McGraw’s Plan
• Dr Phil McGraw’s The Ultimate Weight Solution
is a 7 point plan to lose weight.
• The plan focuses on several lifestyle changes and
ways we behave and think about food.
• Focus on portion size, eating water-rich foods,
intentional exercise, eat slower and not being
distracted- know when you are full.

67

Exercise
• Americans need more exercise.
• The heart is a muscle and becomes stronger with
exercise.
• In addition to the role of exercise in calorie
burning, it also reduces stress and creates a feeling
of inner peace.
• Children don’t play outside as much and play
more non physical games (computers etc).
• Really need at least 20 minutes of physical
exercise 3-4 time per week. Walking is great
68
exercise.

DIET AND CHRONIC
DISEASE

69

The Diet and Disease
• In recent times, we have seen a shift in the
the U.S. and other developed countries from
the lack of nutrition (such as kwashiorkorlack of protein) or lack of certain vitamins
or minerals (goiter, rickets, beriberi, etc.) to
nutritional diseases from over abundance of
certain nutrients (calories).
70

ATHEROSCLEROSIS
• Defined as a number of pathological processes
leading to coronary heart disease, stroke and
diseases of the peripheral circulatory system.
• Cholesterol buildup in arteries- hard on the heart
and circulation.
• First noted in the Korean war.
• Causes include diet, obesity, hypertension,
diabetes, sedentary living, cigarette smoking and
high blood cholesterol levels.
71

Courtesy of USDA

72

HYPERTENSION
• High blood pressure
• Problem with cardiovascular diseases and other
organs like the kidney.
• It has a genetic component but is further
complicated by obesity, lack of physical activity,
emotional stress, cigarette smoking and diet.
• Sodium intake has been shown to increase blood
pressure while calcium has been shown to reduce
it.
73

CANCER
• One third of all cancers are related to diet.
• Stomach and colon cancers related to diets high in
fat and low in fresh fruits and vegetables.
• Excessive consumption of cured and smoked
meats has been associated with an increase in
esophagus and stomach cancers.
• Increased consumption of foods rich in
antioxidants may prevent some cancers.
74

Recommendations
• Eat a variety of foods for a balanced diet. You
MUST reduce caloric intake in some way that
works for you. Learn the different food groups and
learn what portion size is.
• Get plenty of physical exercise- it burns excess
calories and creates a peaceful feeling.
• Eat to live- learn to eat slowly knowing when to
quit; don’t resolve anxiety issues with eating.
75

Need More Information?
• In Arkansas, contact your local county agent
or Nutrition Specialists at the Cooperative
Extension State Office in Little Rock;
501/671-2000
• USDA Website;
www.dga2000training.usda.gov/
www.health.gov/dietaryguidelines/dga2000/
76

77