Chapter 5 Nutrition © 2013 McGraw-Hill Education. All Rights Reserved. Understanding Nutritional Guidelines Dietary Reference Intakes (DRIs): recommended intake levels of essential nutrients for optimal health
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Transcript Chapter 5 Nutrition © 2013 McGraw-Hill Education. All Rights Reserved. Understanding Nutritional Guidelines Dietary Reference Intakes (DRIs): recommended intake levels of essential nutrients for optimal health
Chapter 5
Nutrition
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Rights Reserved.
1
Understanding Nutritional
Guidelines
Dietary Reference Intakes (DRIs): recommended
intake levels of essential nutrients for optimal
health
Recommended Dietary Allowance (RDA):
represents the average daily amount of any one
nutrient to protect against nutritional deficiency
Acceptable Macronutrient Distribution Range
(AMDR): intake levels of essential nutrients that
provide adequate nutrition and reduce risk of
chronic disease
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2
Understanding Nutritional
Guidelines
USDA MyPlate: graphic nutritional tool developed
to accompany the 2010 Dietary Guidelines for
Americans
Daily Values: standards used on food labels to
indicate how a particular food contributes to the
recommended daily intake of major nutrients in a
2,000-calorie diet
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3
Types of Nutrients
Essential nutrients: needed to build, maintain, and repair
tissues and regulate body functions
Macro-nutrients: needed in large amounts
Water, carbohydrates, proteins, fats
Micro-nutrients: needed in small amounts
–
Vitamins, minerals
Calorie: measure of energy provided by food
9 calories per gram of fat
4 calories per gram of carbohydrates and proteins
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Water—The Unappreciated
Nutrient
Function:
Digests, absorbs, transports nutrients
Helps regulate body temperature
Carries waste out of the body
Lubricates our body parts
RDA:
1 to 1.5 milliliters per calorie spent
2 to 3 liters, or 8 to 12 cups of fluid
Water needs can vary depending on several factors, such as foods
consumed and activity level
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5
Carbohydrates—Your Body’s
Fuel
–
The body’s main source of energy
Fuel most of the body’s cells during daily activities
Used by muscle cells during high-intensity exercise
Only source of energy for brain cells, red-blood cells, and some other
types of cells
Types:
Simple carbohydrates (sugars)
Complex carbohydrates (starches and dietary fibers)
RDA:
130 grams for males and females (aged 1–70)
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Simple and Complex
Carbohydrates
Simple carbohydrates:
Easily digestible and composed of one or two units
of sugar
Glucose, fructose, galactose, lactose, maltose,
sucrose
Complex carbohydrates:
Sources:
Whole grains (whole wheat, brown rice, oatmeal, corn)
Vegetables
Some fruit
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Fiber
Complex carbohydrate found in plants that cannot
be broken down by the digestive tract
Fiber allows for passage of food quickly through
the intestines, which helps prevent hemorrhoids
and constipation
RDA:
25 grams/day for women (aged 19-50)
38 grams/day for men (aged 14-50)
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Fiber
Fiber is best obtained through diet, not pills or supplements
Sources of fiber:
Fruits
Vegetables
Dried beans
Peas and other legumes
Cereals
Grains
Nuts
Seeds
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9
Protein—Nutritional Muscle
Function:
Build and maintain muscles, bones, and other body tissues
Form enzymes that facilitate chemical reactions
Types:
Complete proteins
Incomplete proteins
RDA:
0.36 grams per pound of body weight
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Protein—Nutritional Muscle
Complete protein sources
Animal proteins: meat, fish, poultry, milk,
cheese, eggs
Incomplete protein sources
Vegetable proteins: grains, legumes, nuts,
seeds, other vegetables
Complementary proteins: proteins that in
combination provide essential amino acids
Mutual supplementation: nutritional strategy of
combining two incomplete protein sources to
provide a complete protein
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For example, beans and rice
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Fats—A Necessary Nutrient
Principal form of stored energy in the body
Provide essential fatty acids
Role in the production of other fatty acids and Vitamin D
Provide the major material for cell membranes and for the myelin sheaths that
surround nerve fibers
Assist in absorption of fat-soluble vitamins
Affect texture, taste, and smell of foods
Provide emergency reserve when we are sick or when our food intake is
diminished
RDA:
20–35% of calories from fat with only about one-third coming from saturated
fats
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Types of Fat
Saturated fat: found in animal products and other
fats that remain solid at room temperature
Beef
Pork
Poultry
Whole-milk dairy products
Certain tropical oils (coconut and palm)
Certain nuts (macadamia)
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Types of Fat
Monounsaturated fat: found primarily in plant
sources, are liquid at room temperature, and are
semisolid or solid when refrigerated
Olive, safflower, peanut and canola oils
Avocados
Many nuts
Polyunsaturated fat: commonly referred to as
“oil”; liquid at room temperature and when
refrigerated
Corn and soybean oils
Fish, including trout, salmon, and anchovies
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Cholesterol
A waxy substance that is needed for several important
body functions
The body produces it from the liver and obtains it from
animal food sources (meat, cheese, eggs, milk)
Too much cholesterol can clog arteries and lead to
cardiovascular disease
LDLs (low density lipoproteins) are the “bad”
cholesterol, while HDLs (high density lipoproteins) are
considered “good”
Recommended: consume no more than 300 milligrams
per day
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Trans Fats
Liquid vegetable oils that have been chemically changed
through the process of hydrogenation to extend the shelf
life of processed foods
Pose a risk to cardiovascular health by raising LDL levels
and lowering HDL levels
Foods high in trans fatty acids include:
Crackers, cookies, chips
Cakes and pies
Doughnuts
Deep fried foods like French fries
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16
Omega-3 and Omega-6 Fatty
Acids
Omega-3s: contain alpha-linolenic acid, which
helps slow the clotting of blood, improves arterial
health, and lowers blood pressure
Omega-6s: contain linolenic-acid and are
important to health, though they are often
consumed too much by Americans
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Minerals—A Need for Balance
•
Minerals are naturally occurring substances needed by the body in small amounts
–
•
Build strong bones and teeth, and help carry out metabolic processes and body
functions
The body needs 20 essential minerals
–
Macrominerals (need at least 100 mgs/day)
•
–
Microminerals (need less than 100 mgs/day)
•
•
Calcium, chloride, magnesium, phosphorous, potassium, sodium
Chromium, cobalt, copper, fluorine, iodine, iron, zinc, manganese, nickel, and others
A balanced diet provides all the essential minerals the body needs per day
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Vitamins—Small But Potent
Nutrients
Naturally occurring organic substances needed by the
body in small amounts
Serve as catalysts for releasing energy from
carbohydrates, proteins, and fats while maintaining
other body components
Your body needs at least 11 specific vitamins
A, C, D, E, K, and the B-complex vitamins
Vitamins can be found in a variety of foods, so often
supplements are unnecessary
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Dietary Guidelines for Americans
Two-thirds of Americans are now overweight or
obese
Focus is on stopping and reversing the spread of
overweight and obesity
Approaches to change:
Individual
Environmental
Food supply
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Dietary Guidelines for Americans
Four main goals:
Reduce calorie intake and increase physical activity
Move toward a more plant-based diet composed of
nutrient-dense foods
Reduce intake of foods containing added sugars
and solid fats and reduce overall sodium and
refined grain consumption
Meet the 2008 Physical Activity Guidelines provided
by the U.S. Department of Health and Human
Services
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Dietary Guidelines for Americans
Individual calorie requirements are calculated
based on sex and age at three activity levels:
Sedentary: only light physical activity
Moderately active: equivalent to walking 1.5 miles
per day at 3–4 mph
Active: more than 3 miles per day at 3–4 mph
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Dietary Guidelines for Americans
MyPlate: visual icon designed to raise awareness and health
literacy about the different food groups
DASH Eating Plan: Dietary Approaches to Stop Hypertension
Recommendations for specific groups
Children and adolescents
Older adults
Pregnant and breastfeeding women
Overweight adults and children
People with chronic conditions
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Planning a Vegetarian Diet
Vegetarian diets may offer protection against
obesity, heart disease, high blood pressure,
diabetes, digestive disorders, and some forms of
cancer
Vegetarians need to make sure their diets provide
the energy intake and food diversity necessary to
meet dietary guidelines
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Daily Values and Food Labels
FDA regulates food labels
List serving size and number of servings
Give total calories and calories from fat
Look for foods with no more than 30 percent of their
calories from fat
Show how much the food contributes to Daily Values for
important nutrients
FDA’s authority to regulate health claims on front-ofpackage (FOP) food labels is limited
Institute of Medicine found these labels provide little
guidance and cause confusion
Recommended a standard for FOP labels
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Nutrition Facts Food Label
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Current Consumer Concerns
Overconsumption of soft drinks
High-sodium diets
Food allergies and food intolerances
7% of children, 2% of adults have food allergies
Food intolerances such as lactose intolerance are less
severe
Overconsumption of energy bars, energy drinks, and
relaxation drinks
Fast foods
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Current Consumer Concerns
Probiotics, prebiotics, and synbiotics
Probiotics are living bacteria that may aid digestion;
prebiotics are nondigestible carbohydrates that fuel
probiotics
Synbiotics combine the two
Scientific studies have not confirmed health benefits
Food deserts: low-income areas where more than 500
people or 33% have low access to a supermarket
When fresh produce not available, people don’t have
opportunity to choose a healthy diet
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Organic Foods
Plant foods grown without synthetic pesticides or
fertilizers
Animal foods raised on organic feed without
antibiotics or growth hormone
USDA regulates labeling
Research has not demonstrated health benefits,
but environmental benefits are clear
Look for foods that are not only organic but
also locally grown
Wash organic produce thoroughly
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Foodborne Illnesses
Food intoxication: food poisoning in which food is
contaminated by natural toxins
Botulism
Food infection: food poisoning in which food is
contaminated by disease-causing microorganisms, or
pathogens
E. coli, salmonella, campylobacter
Pet food can contain salmonella
Use safe food practices and store food safely,
especially leftovers
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Kitchen Safety
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Genetically Modified Foods
Genetically modified (GM) organisms: genetic makeup
has been changed to produce desirable results
Selective breeding
Modern biotechnology faster and more refined
Many crops are already GM
60% of processed foods in supermarkets contain one or
more GM ingredient
Safety assessed by FDA’s Center for Food Safety and
Applied Nutrition (CFSAN)
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