Nutrition Basics
1
YOU ARE
WHAT YOU
EAT!!!
You are what
you eat!!!
2
Nutrients
• Essential nutrients = substances the
body must get from food because it
cannot manufacture them at all or fast
enough to meet its needs:
– Proteins
– Carbohydrates
– Fats
– Vitamins
– Minerals
– Water
3
Energy from Food
• Kilocalorie = a measure of energy content in
food; the amount of heat it takes to raise the
temperature of 1 liter of water 1°C; commonly
referred to as “calorie”
• Three classes of essential nutrients supply
energy
– Fat = 9 calories per gram
– Protein = 4 calories per gram
– Carbohydrates = 4 calories per gram
*Although alcohol is NOT a nutrient it supplies
seven calories per gram!
4
Proteins—The Basis of Body
Structure
• Protein = a compound made of amino acids that
contains carbon, hydrogen, oxygen, and
nitrogen
• Of twenty common amino acids in foods, nine
are essential
• Proteins form key parts of the body’s main
structural components—muscles and bones—
and of blood, enzymes, cell membranes, and
some hormones
5
Complete and
Incomplete Proteins
• Complete protein sources = foods that
supply all the essential amino acids in
adequate amounts
– Meat, fish, poultry, eggs, milk, cheese, and soy
• Incomplete protein sources = foods that
supply most but not all essential amino
acids
– Plants, including legumes, grains, and nuts
6
Recommended Protein Intake
• Adequate daily intake
of protein
– 0.8 gram per kilogram
(0.36 gram per pound)
of body weight
• Acceptable
Macronutrient
Distribution Range
– 10–35% of total daily
calories as protein
7
Fats - Essential in
Small Amounts
• Fats
– supply energy, insulate the body, support and
cushion organs, absorb fat-soluble vitamins,
add flavor and texture to foods
• Essential fats
– linoleic acid and alpha-linolenic acid are key
regulators of body process such as the
maintenance of blood pressure and the
progress of a healthy pregnancy
8
Types and Sources of Fats
• Saturated fat = a fat with no carbon-carbon
double bonds; usually solid at room
temperature
– Found primarily in animal foods and palm and
coconut oils
– Leading sources in our diets are: red meats,
whole milk, cheese, hot dogs and lunch meats
• Monounsaturated fat = a fat with one
carbon-carbon double bond; usually liquid at
room temperature
– Found in certain vegetables, nuts, and vegetable
oils (olive, canola, safflower, & peanut oils
9
Types and Sources of Fats
• Polyunsaturated fat
– a fat with two or more carboncarbon double bonds; usually
liquid at room temperature
– Found in certain vegetables,
nuts, and vegetable oils
(soybean, corn, & cottonseed
oils) and in fatty fish
10
Types and Sources of Fats
• Two key forms of polyunsaturated fats:
– Omega-3 fatty acids = the endmost double
bond of a polyunsaturated fat occurs three
carbons from the end of the fatty acid chain
• Found primarily in fish
– Omega-6 fatty acids = the endmost double
bond of a polyunsaturated fat occurs six
carbons from the end of the fatty acid chain
• Found primarily in certain vegetable oils,
especially corn, soybean, and cottonseed oils
11
Trans Fatty Acids
• The process of hydrogenation, in
which hydrogens are added to
unsaturated fats,
– produces a mixture of saturated fatty
acids and standard and trans forms of
unsaturated fatty acids
• Trans fatty acids have an atypical
shape that affects their chemical
activity
• Leading sources in our diet are
– french fries, fried chicken, cakes,
cookies, pastries, doughnuts, chips, &
stick margarine
12
Fats and Health
• Fats affect blood cholesterol levels
– Low-density lipoprotein (LDL) = “bad”
cholesterol
– High-density lipoprotein (HDL) = “good”
cholesterol
• Saturated and trans fats raise levels of
LDL; trans fats also lower levels of HDL
• Unsaturated fats lower levels of LDL
13
Fats and Health
• Fats also affect triglyceride
levels, inflammation, heart
rhythm, blood pressure, and
cancer risk
• Best choices
– monounsaturated fats and
polyunsaturated omega-3 fats
• Limit intake of saturated and
trans fats
14
Saturated and Trans Fats:
Comparing Butter and Margarine
Butter
Stick
margarine
Margarine
spread
Saturated fat
Trans fat
Other fats
Tub
margarine
Squeeze
margarine
0
5
10
Grams of fat in 1
tablespoon
15
SOURCE: Food an Drug Administration
15
Total fat grams per serving
Total, Saturated, and Trans Fat
Content of Selected Foods
Other fats
Trans fat
Saturated fat
30
25
20
15
10
5
0
French fries
Doughnut
Pound cake Potato chips
Candy bar
Milk (whole)
SOURCE: Food an Drug Administration
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Recommended Fat Intake
• Adequate daily intake of fat:
Men
Women
Linoleic acid
17 grams
12 grams
Alpha-linolenic acid
1.6 grams
1.1 grams
= about 3–4 teaspoons of vegetable oil
• Acceptable Macronutrient Distribution Range
= 20–35% of total daily calories as fat
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Carbohydrates - An Ideal
Source of Energy
• The primary function of dietary carbohydrate
– to supply energy to body cells.
• Cells in the brain, nervous system, and blood,
– use only carbohydrates for fuel
• During high-intensity exercise,
– muscles get most of their energy from carbohydrates
• During digestion,
– carbohydrates are broken into single sugar molecules
such as glucose for absorption;
– the liver and muscles take up glucose and store it in
the form of glycogen
18
Simple and Complex Carbohydrates
• Simple carbohydrates contain one or two sugar
units in each molecule
– Found naturally in fruits and milk and added to many
other foods
– Include sucrose, fructose, maltose, and lactose
• Complex carbohydrates consist of chains of
many sugar molecules
– Found in plants, especially grains, legumes, and tubers
– Include starches and most types of dietary fiber
19
Whole Grains
 Before they are processed, all
grains are whole grains consisting
of an inner layer of germ, a middle
layer called the endosperm, and
an outer layer of bran
 During processing, the germ and
bran are often removed, leaving
just the starchy endosperm
 Refined carbohydrates usually
retain all the calories of a whole
grain but lose many of the
nutrients
20
Refined Carbohydrates Versus
Whole Grains
• Whole grains are higher than refined
carbohydrates in fiber, vitamins, minerals, and
other beneficial compounds
• Whole grains take longer to digest
– Make people feel full sooner
– Cause a slower rise in glucose levels
• Choose foods that have a whole grain as the
first item on the ingredient list on the label
– Whole wheat, whole rye, whole oats, oatmeal,
whole-grain corn, brown rice, popcorn, barley, etc.
21
Glycemic Index
• Consumption of carbohydrates
– causes insulin and glucose levels in the blood
to rise and fall
• Glycemic index
– is a measure of how the ingestion of a
particular food affects blood glucose levels
• Foods with a high glycemic index
– cause quick and dramatic changes in glucose
levels
• Diets rich in high glycemic index foods
– are linked to increased risk of diabetes and
heart disease
22
Recommended Carbohydrate Intake
• Adequate daily intake of carbohydrate
– 130 grams
• Acceptable Macronutrient Distribution Range
– 45–65% of total daily calories as carbohydrate
• Limit on intake of added sugars
– Food and Nutrition Board:
• 25% or less of total daily calories
– World Health Organization:
• 10% or less of total daily calories
– MyPyramid:
• 32 grams (8 tsp) in a 2000-calorie diet
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Acceptable Macronutrient
Distribution Ranges: Summary
• Protein
– 10–35% of total daily calories
• Fat
– 20–35% of total daily calories
• Carbohydrate
– 45–65% of total daily calories
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Fiber - A Closer Look
• Dietary fiber
– nondigestible carbohydrates and lignin that are
present naturally in plants
• Functional fiber
– nondigestible carbohydrates isolated from
natural sources or synthesized in a lab and
added to a food or supplement
• Total fiber
– dietary fiber + functional fiber
• Fiber does not provide calories
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Types of Fiber
• Soluble (viscous) fiber
– fiber that dissolves in water or is broken down by
bacteria in the large intestine (oat bran, legumes)
– Slows the body’s absorption of glucose
– Binds cholesterol-containing compounds
• Insoluble fiber
– fiber that doesn’t dissolve in water (wheat bran, psyllium
seed)
– Makes feces bulkier and softer
– Helps prevent constipation, hemorrhoids, and
diverticulitis
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Sources of Fiber
• All plant foods contain fiber, but processing
can remove it
• Good sources of fiber:
– Fruits (especially whole, unpeeled fruits)
– Vegetables
– Legumes
– Oats (especially oat bran)
– Whole grains and wheat bran
– Psyllium (found in some cereals and laxatives)
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Recommended Intake of Fiber
• Women
– 25 grams per day
• Men
– 38 grams per day
• Americans currently
consume
– about half this amount
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Vitamins—Organic
Micronutrients
• Vitamins
– organic (carbon-containing) substances needed
in small amounts to help promote and regulate
chemical reactions and processes in body cells.
• Four vitamins are fat-soluble
– Vitamin A, D, E, and K
• Nine vitamins are water-soluble
– C and the eight B-complex vitamins: thiamin,
riboflavin, niacin, vitamin B-6, folate, vitamin B12, biotin, and pantothenic acid
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Vitamins
• Vitamins are abundant in fruits,
vegetables, and grains; they are
also added to some processed
foods
• If you consume too much or too
little of a particular vitamin,
characteristic symptoms of excess
or deficiency can develop
• It is best to obtain most of your
vitamins from foods rather than
supplements
30
Minerals- Inorganic Micronutrients
• Minerals = inorganic (non-carbon-containing)
compounds needed in small amounts
– for regulation, growth, and maintenance of body tissues
and functions
• There are about 17 essential minerals:
– Major minerals (those that the body needs in amounts
exceeding 100 mg per day) include calcium,
phosphorus, magnesium, sodium, potassium, and
chloride
– Essential trace minerals include copper, fluoride, iodide,
iron, selenium, and zinc
31
Minerals
• If you consume too much or too little of a
particular mineral, characteristic symptoms
of excess or deficiency can develop
• Minerals commonly lacking in the American
diet:
– Iron = low intake can cause anemia
– Calcium = low intake linked to osteoporosis
– Potassium = low intake linked to elevated blood
pressure and bone mineral loss
– Magnesium
32
Osteoporosis - Thinning of Bones
• Dietary factors that build bone
mass:
–
–
–
–
Calcium
Vitamin D
Vitamin K
Other possible dietary factors:
vitamin C, magnesium,
potassium, manganese, zinc,
copper, boron
• Weight-bearing exercise and
strength training also build and
maintain bone mass
• Dietary factors linked to
loss of bone mass:
–
–
–
–
–
–
Alcohol
Sodium
Caffeine
Retinol
Soda
Protein (if intake of calcium
and vitamin D is low)
33
Water - A Vital Component
• Human body is composed of about 50–60%
water;
– you can live only a few days without water
• Foods and fluids you consume provide 80–90%
of your daily water intake
• Adequate intake to maintain hydration:
– Women = about 9 cups of fluid per day
– Men = about 13 cups of fluid per day
• Drink in response to thirst;
– consume additional fluids for heavy exercise
34
Other Substances in Food:
Antioxidants
• Antioxidant
– a substance that protects against the breakdown of body
constituents by free radicals;
– actions include binding oxygen, donating electrons to free
radicals, and repairing damage to molecules
• Free radical - a chemically unstable, electron-seeking compound
that can damage cell membranes and mutate genes in its search
for electrons
• Many fruits and vegetables are rich in antioxidants
such as vitamin C, vitamin E, selenium, and
carotenoids
35
Other Substances in Food:
Phytochemicals
• Phytochemical
– a naturally occurring substance found in plant foods that
may help prevent and treat chronic diseases
• Examples:
– Certain proteins in soy foods
– Sulforaphane in cruciferous vegetables (cabbage,
broccoli, brussels sprouts, kale, cauliflower)
– Allyl sulfides in garlic and onions
• Fruits and vegetables are rich in phytochemicals
36
Nutritional Guidelines:
Planning Your Diet
• Dietary Reference Intakes (DRIs)
– standards for levels of nutrient intake to prevent nutrient
deficiencies and reduce the risk of chronic disease
• Dietary Guidelines for Americans
– general principles of good nutrition intended to help
prevent certain diet-related diseases
• MyPyramid
– a food-group plan that provides practical advice to
ensure a balanced intake of essential nutrients
37
Dietary Reference Intakes
(DRIs)
• Set by the Food and Nutrition Board of the
National Academies
• Recommended Dietary Allowance (RDA) or
Adequate Intake (AI) = recommended intake
• Tolerable Upper Intake Level (UL)
– maximum daily intake unlikely to cause health
problems
• Example of calcium recommendations for an
18-year-old woman:
– RDA = 1300 mg/day
– UL = 2500 mg/day
38
Should You Take Supplements?
• The Food and Nutrition Board recommends
supplements only for certain groups:
– Folic acid for women capable of becoming
pregnant (400 µg/day)
– Vitamin B-12 for people over age 50 (2.4
mg/day)
• Other possible situations for supplements:
– Vitamin C for smokers
– Iron for menstruating women
– Vitamin K for newborns
– People with certain special health concerns
39
Daily Values
• Daily Values
– a simplified version of the RDAs used on
food labels
• Also included in Daily Values are
standards for nutrients with no
established RDA
• Shown on food labels in terms of a
2000-calorie diet
40
Dietary Guidelines for
Americans
• Adequate Nutrients within Calorie Needs
– Focus on nutrient dense foods.
– Eat more dark green vegetables, orange
vegetables, legumes, fruits, whole grains, and
low-fat and fat-free milk and milk products.
– Eat less refined grains, saturated fat, trans fat,
cholesterol, added sugars, and calories.
– Plans that meet the goals include MyPyramid
and DASH.
41
Dietary Guidelines for
Americans
• Weight Management
– Evaluate body weight in
terms of BMI.
– Balance food intake and
physical activity to avoid
weight gain.
– To lose weight, decrease
calorie intake, maintain
adequate nutrient intake, and
increase physical activity.
42
Dietary Guidelines for
Americans
• Physical Activity
– 30 minutes per day to reduce
risk of chronic disease
– 60 minutes per day to prevent
weight gain
– 60-90 minutes per day to
sustain weight loss
43
Dietary Guidelines for
Americans
• Food Groups to
Encourage
– Fruits and vegetables—
choose a variety of colors
and kinds
– Whole grains—half of all
servings of grains should
be whole grains
– Low-fat and fat-free milk
and milk products
44
Dietary Guidelines for
Americans
• Fat Intake Goals
– Total fat: 20-35% of total daily
calories
– Saturated fat: Less than 10% of total
daily calories
– Trans fat: As little as possible
– Cholesterol: Less than 300 mg per
day
45
Dietary Guidelines for
Americans
• Carbohydrate Intake
– Choose high-fiber foods
– Limit intake of added sugars
• Sodium and Potassium
– Limit sodium intake
• 2300 mg per day; 1500 mg per day for those at
high risk
– Consume adequate potassium
• Alcohol intake—moderate if at all
46
MyPyramid
• Food guidance system that promotes
healthy food choices and physical
activity
• Choosing a balance of servings from
different food groups meets nutrient
needs and reduces chronic disease risk
• Balancing food choices and activity
promotes weight management
47
MyPyramid
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MyPyramid: Grains
• For a 2000-calorie diet
– choose 6 ounce-equivalents per day
• 1 ounce-equivalent:
–
–
–
–
1 slice of bread
1 small muffin
1 cup ready-to-eat cereal flakes
1/2 cup cooked cereal, rice, grains,
pasta
– 1 6-inch tortilla
49
MyPyramid: Vegetables
• For a 2000-calorie diet,
– choose 2-1/2 cups (5
servings) per day
• 1/2 cup or equivalent:
– 1/2 cup raw or cooked
vegetables
– 1/2 cup vegetable juice
– 1 cup raw leafy salad
greens
50
MyPyramid: Vegetables
• Choose vegetables from five groups:
– Dark green vegetables
• spinach, kale, collards, bok choy, other leafy
greens
– Orange and deep yellow vegetables
• carrots, winter squash, sweet potatoes
– Legumes
– Starchy vegetables
• corn, potatoes, peas
– Others (e.g., tomatoes, bell peppers, green
beans, cruciferous vegetables)
51
MyPyramid: Fruits
• For a 2000-calorie diet,
choose 2 cups (4 servings) per
day
• 1/2 cup or equivalent:
– 1/2 cup fresh, canned, or frozen
fruit
– 1/2 cup fruit juice (100% juice)
– 1 small whole fruit
– 1/4 cup dried fruit
• Choose whole fruits often
52
MyPyramid: Milk
• For a 2000-calorie diet, choose
3 cups or the equivalent per day
• 1 cup or equivalent:
–
–
–
–
1 cup milk or yogurt
1/2 cup ricotta cheese
1-1/2 ounces natural cheese
2 ounces processed cheese
• Choose low-fat and fat-free
items
53
MyPyramid: Meat and Beans
• For a 2000-calorie diet, choose 5-1/2 ounceequivalents per day
• 1-ounce equivalents:
–
–
–
–
–
1 ounce cooked lean meat, poultry, fish
1/4 cup tofu or cooked legumes
1 egg
1 tablespoon peanut butter
1/2 ounce nuts or seeds
• Choose lean cuts, limit serving sizes, and try
one plant protein source daily
54
MyPyramid: Oils
• For a 2000-calorie diet, choose 6
teaspoons per day
• 1 teaspoon or equivalent:
– 1 teaspoon vegetable oil or soft margarine
– 1 tablespoon salad dressing or light
mayonnaise
– Food sources: 8 large olives, 1/6 medium
avocado, 1/2 tablespoon peanut butter, 1/3
ounce roasted nuts
55
The Vegetarian Alternative
• Types of vegetarian diets
– Vegan
• vegetarian who eats no animal products
– Lacto-vegetarian
• vegetarian who includes milk and cheese products
in the diet
– Lacto-ovo-vegetarian
• vegetarian who includes milk and cheese products
and eggs in the diet
– Partial vegetarian, semivegetarian, or
pescovegetarian
• vegetarian who includes eggs, dairy products, and
small amounts of poultry and seafood in the diet
56
Vegetarian Diets and Health
• Vegetarian diets
– are lower in saturated fat and cholesterol
– higher in complex carbohydrates, fiber,
folate, vitamins C and E, carotenoids, and
phytochemicals
• Nutrients of concern for vegetarians
– vitamin B-12, vitamin D, calcium, iron, and
zinc
57
Dietary Challenges for Special
Population Groups
• Women
– nutrient density, calcium, iron
• Men
– fruits, vegetables, grains
• College students
– overall quality of food choices
• Older adults
– nutrient density, fiber, vitamin B-12
• People with special health concerns
– discuss with physician or dietitian
58
Food Labels
Read labels to
learn more
about
your food
choices.
59
Dietary Supplements
• May contain powerful
bioactive chemicals
• Not regulated the way
drugs are by the FDA in
terms of testing and
manufacture
• May interact with
prescription and over-thecounter drugs and
supplements
60
Foodborne Illness
• Most caused by pathogens (disease-causing
microorganisms)
• You can’t tell by taste, smell, or sight whether
a food is contaminated
• To prevent foodborne illness
– handle, cook, and store foods in ways that prevent
microorganisms from spreading and multiplying
• New threat
– bovine spongiform encephalopathy (BSE or “mad
cow disease”)
61
Food
Safety
• Cook foods to an
appropriate temperate
• Keep hot foods hot
and cold foods cold
62
Organic Foods
• Organic
• a designation applied to foods grown and
produced according to strict guidelines
limiting the use of pesticides, nonorganic
ingredients, hormones, antibiotics, genetic
engineering, irradiation, and other practices
• Organic foods tend to have lower levels of
pesticide residues than conventionally
grown crops
63
Food Additives
• Most widely used
– are sugar, salt, corn syrup, citric acid,
baking soda, vegetable colors,
mustard, pepper
• Concerns about some additives:
– Monosodium glutamate (MSG)
causes some people to experience
episodes of sweating and increased
blood pressure
– Sulfites cause severe reactions in
some people
– Check food labels
64
Genetically Modified Foods
• GM organism
– a plant, animal, or microorganism in which
genes have been added, rearranged, or
replaced through genetic engineering
• Many GM crops are already grown in
the United States
– soybeans, corn
• No labeling requirement unless a GM
food contains a known allergen
65
Food Allergies
• Reaction by the immune system to
a food or food ingredient
• Common food allergens
– peanuts, milk, eggs, tree nuts, soy,
wheat, fish, and shellfish
• Severe allergic responses can
include anaphylaxis
66
Food Intolerance
• More common than true food allergies
• Reaction to a food or food ingredient,
– usually based on a problem with metabolism
• Common intolerances include lactose
intolerance,
– in which people are deficient in the enzyme lactase,
and gluten intolerance
• Problems can be avoided
– by avoiding or limiting trigger foods
• Keep a food diary to help identify problems
67
A Personal Plan: Applying
Nutritional Principles
• Assess your current diet
• Set reasonable goals for change
• Try additions and substitutions to bring
your current diet closer to your goals
• Adjust one meal or eating habit at a
time
• Plan ahead for challenging situations
68
Web Site Resources
• American Dietetic Association: www.eatright.org
• American Heart Association:
www.deliciousdecisions.org
• FDA Center for Food Safety & Applied Nutrition:
http://vm.dfsan.fda.gov
• Gateways to Government Nutrition Information:
www.foodsafety.gov www.nutrition.gov
69
Web Site Resources, con’t.
• Harvard School of Public Health Nutrition Source:
www.hsph.harvard.edu/nutritionsource
• Choose My Plate: http://www.choosemyplate.gov/
• National Cancer Institute:http://5aday.nci.nih.gov
• Tufts University Nutrition Navigator:
http://navigator.tufts.edu
70
Web Site Resources, con’t.
•
•
•
•
Pepsico: www.smartspot.com
Fast Food Facts: www.foodfacts.info
My Fitness Pal: www.myfitnesspal.com
Self Nutrition Data:
http://nutritiondata.self.com/tools/calorie
s-burned
71