Transcript Document

Nutrition Basics
Chapter 12
© 2008 McGraw-Hill Higher Education. All rights reserved.
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The Body’s Nutritional Requirements
• Essential nutrients
– Are defined as nutrients one
must obtain from diet (digestive
system) b/c body does not mk.
them in adequate amounts
– The Six Essential Nutrients are:
Proteins, Fats, Carbohydrates,
Vitamins, Minerals, Water
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The Body’s Nutritional Requirements
• What is a Calorie (C)?
• Defined as the amount of heat it takes to raise
the temperature of 1L of water 1°C
• Daily requirement: 2000 kilocalories
• One pound is equal to:
• Of the six essential nutrients, only three
supply energy:
– Fats supply = 9 calories/gram
– Protein supply= 4 calories/gram
– Carbohydrates supply= 4 calories/gram
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Lipids (Fats)
• There are three main classes of lipids:
1) Steroids 2) Phospholipids and
3) Triglycerides (food fats)
• Triglycerides
– Are a stored energy
– Function: Insulation, support, absorption of fatsoluble vitamins (A,D,E & K)
– Can be saturated or unsaturated
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Fats and Your Health
• Hydrogenation
– A chemical reaction between hydrogen &
another compound that increases the
degree of saturation in unsaturated fats
– Increases stability of fat
–Trans Fatty Acids are formed in the
process
• Increases LDL, decreases HDL
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Which Foods Have Partially Hydrogenated
Oils?
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Fats and Your Health
• Basic Types of Cholesterol (A Steroid)
– HDL’s are High Density Lipo-Protein or “good”
cholesterol
– LDL’s are Low Density Lipo-Protein or “bad”
cholesterol
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Fats and Your Health
• Beneficial Fats (polyunsaturated fats)
– Omega-3 fatty acids (reduces blood clotting,TGs,)
• Found in some fish, nuts, vegetables
• Reduces blood clotting, lowers TG
– Alpha linolenic acid
• A type of Omega 3
• Found in flax seed, canola, soy bean oils
– Alpha lipoic acid
• Acts as an antioxidant seeming to prevent cell damage
• Found in heart, liver ,kidneys, and vegetables such as
broccoli and spinach.
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Fats and Your Health
• Recommended Intake
– AMDRs = 20-35% (daily calories)
– Healthy Fats are obtained from sources rich in
unsaturated fats (flax,olive, canola, soybean,
oils, etc.)
– Unhealthy/Less Healthy fats are obtained
from sources rich in saturated fats (animal
products, esp. red meat)
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Fats and Your Health
• Dangers of high fat diets
-Difficulty managing weight
-Obesity, heart disease, etc.
-Increased risk of cancer
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PROTEINS
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Proteins
• Proteins are the main components of muscle,
bone, blood, enzymes, hormones and cell
membranes etc.
• There are Complete and Incomplete proteins
– Complete proteins provide all essential amino
acids (20)
– Incomplete have most essential a.a.
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Proteins
• Recommended Intake
– AMDRs =10-35% (daily calories)
– Obtained from lean meat, poultry, fish,
tofu, etc.
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CARBOHYDRATES
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Carbohydrates
• Are Simple and Complex sugars
• They provide fuel for cells
• Two groups:
– Simple Carbohydrates
• Small
• Examples: glucose, lactose, sucrose (fruit, sugar, honey, milk)
– Complex Carbohydrates
• Larger
• Examples: Starch and fiber (Grains, legumes,Tubers)
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Complex Carbohydrates: Whole vs.
Refined Grains
• Grains before
processing = Whole
Grains
• Whole Grains
Contain:
– Inner layer, (germ)
– Middle layer,
(endosperm)
– Outer layer, (bran)
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Complex Carbohydrates: Whole vs.
Refined Grains
• Grains after
processing = Refined
Grains
– Germ and bran
removed leaving
starchy endosperm
– Retain calories, lower
in fiber
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A Closer Look at Fiber
• Dietary fiber- nondigestible carbohydrates
present in plant s (grains, legumes,
vegetables)
• Functional fiber – isolated/made in a lab and
added to food/dietary supplement
• Fiber helps increase fecal bulk
• Recommended intake = 38 grams (men) 25
grams (women)
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The Glycemic Index
• The Glycemic Index (GI) is a numerical
scale used to indicate how fast and how
high a particular food can raise our blood
glucose (blood sugar) level
– High glycemic index foods may increase
appetite
– May increase risk of diabetes and heart
disease
• Foods w/ a Low Glycemic index:
– Whole grains
– Fruits
– Vegetables and legumes
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Carbohydrates
• Recommended carbohydrate intake
– AMDRs = 45-65% (daily calories)
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Vitamins
• Organic
• Aid in chemical reactions; important in RBC
production
• Required in small amounts
• Humans need 13 vitamins:
– Four Fat Soluble: A, D, E, and K.
– Nine Water Soluble: C and B complex vitamins
• (Thiamin, (B1), Riboflavin (B2), Niacin (B3), Pyridoxine (B6),
Folate, B-12, Biotin and Pantothenic acid)
• Sources:
– Fruits, vegetables and grains
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Minerals
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Inorganic
Help regulate body functions
Growth & maintenance of body tissues
17 essential minerals
– Major minerals: needed in excess of 100
mg/day
•
(Ca 2+, P, Mg+, Na+, K+, Cl-)
– Trace Minerals: needed in small amounts
•
(Cu, Fl, I, Fe, Se, Zn etc.)
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Water
• Human body = 60% water
• Food and fluid intake provide 80-90%;
metabolism provides the rest
• Men need ~4 L (3 L from beverages);Women
need ~3 L (2 L from bev.)
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Other substances in food
• Antioxidants
– Function: Protect body from free radical
damage
• Examples:
– Phytochemicals :
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Food Safety
• Causes of foodborne Illnesses:
– Mainly bacteria
– Fewer viruses
– Can cause cramps, gastroenteritis, nausea,
vomiting, etc.
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Food Safety
• Environmental Contaminants
– Contaminants in food growing environment
– Examples: Minerals, antibiotics, hormones,
pesticides industrial chemicals
– Effects of contaminants depends on:
• Concentration
• Length of exposure
• Age/status of person ingesting food
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Food Safety
Food Additives are Added to :
(1) Maintain or improve nutritional quality
(2) Maintain freshness
(3) Help in processing or preparation
(4) Alter taste and appearance
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Food Safety
• Organic foods
– Limits on pesticide residues
– Animals given organic feed; Animals have
access to outdoors
– No antibiotics or growth hormones given to
animals
– Genetic engineering is prohibited
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Dietary Guidelines for Americans
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Eat a variety of nutrient-dense foods
Control calorie intake
Be physically active every day
Eat plenty of grains, vegetables and fruits
Choose fats wisely
Choose carbohydrates wisely
Use little salt and sugar
Moderation of alcohol consumption
Keep foods safe to eat
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My Pyramid
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Vegetarians
• Types:
– Vegans (plants
only)
– Lacto-vegetarians
(plant & dairy)
– Lacto-ovovegetarians
(plants, dairy,
eggs)
• Require : Vitamin
B-12, Vitamin D,
Calcium, Iron , zinc
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