Chapter Twelve
Nutrition Basics
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
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
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
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
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
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
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
• Monounsaturated fat = a fat with one carbon-carbon
double bond; usually liquid at room temperature
– Found in certain vegetables, nuts, and vegetable oils
• Polyunsaturated fat = a fat with two or more carbon-
carbon double bonds; usually liquid at room
temperature
– Found in certain vegetables, nuts, and vegetable oils and in
fatty fish
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
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
Trans Fatty Acids
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
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
Saturated and Trans Fats: Comparing
Butter and Margarine
Butter
Stick
margarine
Margarine
spread Saturated fat
Tub Trans fat
margarine Other fats
Squeeze
margarine
0 5 10 15
Grams of fat in 1 SOURCE: Food an Drug Administration
tablespoon
Total, Saturated, and Trans Fat
Content of Selected Foods
30 Other fats
Total fat grams per serving
Trans fat
25
Saturated fat
20
15
10
5
0
French fries Doughnut Pound cake Potato chips Candy bar Milk (whole)
SOURCE: Food an Drug Administration
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
Carbohydrates—An Ideal Source
of Energy
• The primary function of dietary carbohydrate is 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
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
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
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.
Glycemic Index
• Consumption of carbohydrates causes insulin and
glucose levels in the blood to rise and fall
• Glycemic index = 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
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
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
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
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
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)
Recommended Intake of Fiber
• Women = 25 grams per day
• Men = 38 grams per day
• Americans currently consume about half
this amount
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 (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 B-12, biotin, and pantothenic acid)
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
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
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
Osteoporosis—Thinning of Bones
• Dietary factors that build bone • Dietary factors linked
mass: to loss of bone mass:
– Calcium – Alcohol
– Vitamin D – Sodium
– Vitamin K
– Caffeine
– Other possible dietary factors:
vitamin C, magnesium, potassium,
– Retinol
manganese, zinc, copper, boron – Soda
• Weight-bearing exercise and – Protein (if intake of
strength training also build and calcium and vitamin D
maintain bone mass is low)
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
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
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
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
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
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
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
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.
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.
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
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
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
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
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
MyPyramid
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
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
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)
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
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
MyPyramid: Meat and Beans
• For a 2000-calorie diet, choose 5-1/2 ounce-
equivalents 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
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
MyPyramid: Discretionary Calories
• If nutrient-dense forms are selected from food
groups, the remaining discretionary calories may
be used to increase intake of fats or added
sugars.
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
Vegetarian Diets and Health
• Vegetarian diets are lower in saturated fat and
cholesterol and higher in complex
carbohydrates, fiber, folate, vitamins C and E,
carotenoids, and phytochemicals
• Nutrients of concern for vegetarians include
vitamin B-12, vitamin D, calcium, iron, and zinc
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
Food Labels
Read labels to
learn more
about
your food choices.
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-the-
counter drugs and supplements
Foodborne Illness
• Most foodborne illness is 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‖)
Food
Safety
• Cook foods to an
appropriate temperate
• Keep hot foods hot
and cold foods cold
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
Environmental Contaminants
• Follow FDA/EPA limits for fish consumption
to avoid consuming excess mercury
• Consider the sources of fish (farmed vs. wild)
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
Irradiated Foods—A Technique
of Biotechnology
• Food irradiation = treatment
of foods with gamma rays, X
rays, or high-voltage
electrons to kill potentially
harmful pathogens and
increase shelf life
Genetically Modified Foods
• GM organism = a plant, animal, or
microorganism in which genes have been
addded, 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
Food Allergies
• Reaction by the immune system to a food or
food ingredient
• Common food allergens include peanuts, milk,
eggs, tree nuts, soy, wheat, fish, and shellfish
• Severe allergic responses can include anaphylaxis
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
A Personal Plan: Applying
Nutritional Principles
• Assess your current diet
• Set goals for change
• Try additions and substitutions to bring your
current diet closer to your goals
• Plan ahead for challenging situations
Chapter Twelve
Nutrition Basics