1. Chapter 5 – Nutrition
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Nutrition
LectureOutline
I. The Building Blocks of Good Nutrition
A. Introduction
1. Macronutrients are nutrients required by the human body in the greatest
amounts, including water, protein, carbohydrates, and fats.
2. We also need vitamins and minerals, micronutrients, but only in very
small amounts.
3. Calories are the amount of energy that can be derived from
macronutrients. The number of calories you need depends on:
a. Gender, age, body-frame size, weight, percentage of body fat, and
basal metabolic rate (BMR).
b. BMR is the number of calories needed to sustain your body at rest.
c. Your need for macronutrients depends on how much energy you
expend. Adults should get the following percentages in their diet:
i. 45–65 percent of calories from carbohydrates
ii. 20–35 percent from fat
iii. 10–35 percent from protein
B. Essential Nutrients
1. Every day your body needs certain essential nutrients that provide
energy, build and repair body tissues, and regulate body functions.
2. The six classes of essential nutrients are water, protein, carbohydrates,
fats, vitamins, and minerals.
3. Water
a. Water, which makes up 85 percent of blood, 70 percent of muscles,
and about 75 percent of the brain, performs many essential functions
including carrying nutrients, maintaining temperature, lubricating
joints, helping with digestion, ridding the body of water through
urine, and contributing to the production of sweat, which evaporates
from the skin to cool the body.
b. To ensure adequate water intake, nutritionists advise drinking
enough so that your urine is not dark in color.
4. Protein
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a. Critical for growth and repair proteins form the basic framework for
our muscles, bones, blood, hair, and fingernails.
b. Proteins are made of combinations of 20 amino acids, nine of which
we must get from our diet because the human body cannot produce
them. These are called essential amino acids.
c. A complete protein, or high-quality protein, source provides all of the
essential amino acids. Animal-based foods are considered sources.
d. Incomplete proteins are low in one or more of the essential amino
acids.
e. Complementary proteins are two or more incomplete protein sources
that together provide adequate amounts of all the essential amino
acids.
f. The average person needs 50 to 65 grams of protein daily.
5. Carbohydrates
a. Organic compounds that provide our brains and bodies with glucose,
their basic fuel.
b. The major sources of carbohydrates are plants—including grains,
vegetables, fruits, and beans—and milk.
c. All provide 4 calories per gram and adults and children should
consume at least 130 grams each day.
d. Simple carbohydrates
i. Include natural sugars, such as the lactose in milk and the fructose
in fruit, and added sugars that are found in candy, soft drinks, fruit
drinks, and other sweets.
ii. High-fructose corn syrup might stimulate the pancreas to produce
more insulin. It also makes beverages very sweet, which may
increase consumption and contribute to obesity and other health
problems.
e. Complex carbohydrates
i. Examples are grains, cereals, vegetables, beans, and nuts.
ii. Whole grains are made up of all the components of the grain,
including the bran (fiber-rich outer layer), the endosperm (middle
layer), and the germ (nutrient-packed inner layer).
f. Low-Carb Foods
i. Although many people may believe that low-carb foods are
healthier, that is not necessarily true.
g. Fiber
i. Dietary fiber is the nondigestible form of complex carbohydrates
occurring naturally in plant foods, such as leaves, stems, skins,
seeds, and hulls.
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ii. Functional fiber consists of isolated, nondigestible carbohydrates
that may be added to foods that provide beneficial effects in
humans.
iii. Total fiber is the sum of dietary fiber and functional fiber.
iv. Benefits of fiber: creates a feeling of fullness and aids in weight
control, interferes with the absorption of dietary fat and cholesterol,
and helps prevent constipation and diabetes. Fiber may also
contribute to a longer lifespan.
v. The Institute of Medicine recommends 38 grams of daily total fiber
for men and 25 grams for women.
vi. Good sources of fiber include wheat and corn bran; leafy greens;
the skins of fruits and root vegetables; oats, beans, and barley; and
the pulp, skin, and seeds of many vegetables and fruits, such as
apples and strawberries.
h. Glycemic Index and Glycemic Load
i. Glycemic index is a ranking of carbohydrates, gram for gram,
based on their immediate effect on blood glucose levels.
ii. Glycemic load is a measure of how much a typical serving size of a
particular food raises blood glucose.
6. Fats
a. Fats carry the fat-soluble vitamins A, D, E, and K; aid in their
absorption in the intestine; protect organs from injury; regulate body
temperature; and play an important role in growth and development.
b. They provide 9 calories per gram.
c. Forms of Fat
i. Saturated fats are normally solid at room temperature.
ii. Trans fats are formed when liquid vegetable oils are processed to
make table spreads or cooking fats; also found in dairy and beef
products; considered to be especially dangerous dietary fats.
iii. Unsaturated fats can be divided into monounsaturated and
polyunsaturated fats and are found in olive, soybean, canola,
cottonseed, corn, and other vegetable oils.
iv. Omega-3 and omega-6 are polyunsaturated fatty acids with slightly
different chemical compositions.
(a) Omega-3 fatty acids are found in salmon, sardines, flaxseed,
and walnuts.
(b) Omega-3 fatty acids help to prevent blood clots, protect against
irregular heartbeats, and lower blood pressure.
(c) Omega-6 fats are found in vegetable oils, nuts, seeds, meat,
poultry, and eggs.
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(d) The American Heart Association recommends two servings of
fish a week.
7. Vitamins
a. Vitamins help put proteins, fats, and carbohydrates to use, are
essential to regulating growth, maintaining tissue, and releasing
energy from foods.
b. The fat soluble vitamins are A, D, E, and K.
c. The B vitamins and vitamin C are water soluble.
d. Antioxidants are substances that prevent the harmful effects caused
by oxidation within the body.
i. These include vitamin C and E and beta-carotene as well as
compounds like carotenoids and flavonoids.
e. Folic Acid
i. Folic acid, or folate, a B vitamin, reduces the risk of neural tube
defects in children.
f. Vitamin D
i. Essential for bone health, cognitive function, pain control, and
many other processes.
ii. Vitamin D3 is formed in the skin after exposure to the sun’s
ultraviolet rays and ingested from animal sources, including some
fish.
iii. Vitamin D can also be found in fortified foods such as milk, cheese,
bread, and juice.
iv. The benefits of vitamin D include:
(a) Lower risk of heart disease
(b) Decreased blood pressure
(c) Protection against infection
(d) Formation and maintenance of strong bones
(e) Better absorption of calcium
v. Low levels of vitamin D can contribute to heart disease, falls and
broken bones, breast cancer, prostate cancer, depression, memory
loss, Parkinson’s disease, and stroke.
8. Minerals
a. Minerals help build bones and teeth, aid in muscle function, and help
our nervous systems transmit messages.
b. Calcium
i. Calcium, the most abundant mineral in the body, builds strong
bone tissue throughout life and plays a vital role in blood clotting,
and muscle and nerve functioning.
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ii. Adequate vitamin D and calcium intake during childhood,
adolescence, and young adulthood is crucial for preventing
osteoporosis.
c. Sodium
i. Sodium helps maintain proper fluid balance, regulates blood
pressure, transmits muscle impulses, and relaxes muscles.
ii. The National Heart, Lung, and Blood Institute recommends less
than one tablespoon of table salt a day.
9. Phytochemicals
a. Compounds that exist naturally in plants.
b. Serve many functions including helping a plant protect itself from
bacteria and disease.
c. In the body, they act as antioxidants, mimic hormones, and reduce the
risk of various illnesses, including cancer and heart disease.
10. Dietary Supplements
a. More than half of adults in the United States use dietary supplements,
most often to improve or maintain overall health. However, many
supplements, including vitamins C and E, have failed to deliver on
their promised benefits in rigorous, randomized controlled trials.
II. Dietary Guidelines for Americans
A. Introduction
1. Recommendations from the most recent Dietary Guidelines for Americans
encompass two overarching concepts:
a. The key to achieving and sustaining a healthy weight is to maintain
calorie balance.
b. Americans should focus on consuming nutrient-dense foods and
beverages.
B. Balancing Calories to Manage Weight
1. Calorie balance refers to the relationship between calories expended in
normal body functions and through physical activity.
2. To maintain a healthy weight, you must expend as much energy (calories)
as you take in.
C. Foods and Food Components to Reduce
1. Sodium
a. Nine in 10 Americans consume more sodium than they need.
b. To lower your sodium intake:
i. Look for labels that say “low sodium.”
ii. Learn to use spices and herbs rather than salt to enhance the flavor
of food.
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iii. Go easy on condiments such as soy sauce, ketchup, and mustard.
iv. Always check the amount of sodium in processed foods such as
frozen dinners and salad dressings.
c. Dietary Guidelines recommend that all Americans consume no more
than 2300 mg per day.
2. Fats
a. The Dietary Guidelines call for reducing the number of calories from
solid fats, which are abundant in the diets of Americans and
contribute significantly to excess calorie intake.
b. Forms of Fat
i. The America Heart Association recommends that people restrict
saturated fats to as little as 5 percent of daily calories.
ii. To reduce saturated fat intake:
(a) Cut back on the major sources of saturated fats such as bacon,
regular cheese, and diary-based desserts.
(b) Switch to nonfat or low-fat milk and dairy products.
(c) Chose grilled, baked, broiled or poached fish.
(d) Trim all visible fat from meat.
(e) Use oils that are rich in monounsaturated fatty acids.
iii. Dietary Guidelines recommend consuming less than 10 percent of
calories from saturated fatty acids and replacing them with
monounsaturated and polyunsaturated fatty acids.
c. Trans-Fatty Acids
i. An increased intake of trans-fatty acids has been linked with higher
levels of LDL and heart-harming cholesterol and a greater danger
of heart disease.
d. Cholesterol
i. The body makes more cholesterol than it uses, and people do not
need additional amounts.
ii. The main sources of cholesterol, which is found only in animal
foods, include eggs, chicken, and beef.
3. Added Sugars
a. The major sources of added sugars are soda, energy drinks, sports
drinks, grain-based desserts, sugar-sweetened fruit drinks, dairy-
based desserts, and candy.
4. Refined Grains
a. Refining whole grains involves a process that removes vitamins,
minerals, and fiber.
b. Many refined grain products are also high in solid fats and added
sugars.
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c. Dietary Guidelines urge replacing refined grains with whole grains so
that at least half of all grains consumed are whole.
5. Alcohol
a. There is no nutritional need for alcohol.
b. Moderate consumption is associated with a lower risk of heart
disease; however, it is also linked with an increased risk of breast
cancer, violence, drowning, and injuries from falls and motor vehicle
crashes.
D. Foods and Nutrients to Increase
1. Vegetables and Fruits
a. Dietary Guidelines recommend eating more vegetables and fruit.
b. Vegetables and fruit provide many nutrients, lower the risk of many
chronic illnesses, cardiovascular disease, and may protect against
certain types of cancer.
c. To increase your fruit and vegetable intake:
i. Toss fruit into a green salad.
ii. Start the day with a double serving of fruit for breakfast.
iii. Buy precut vegetables.
iv. Make or order sandwiches with extra tomatoes or other vegetables.
v. Fill half your dinner plate with vegetables.
2. Whole Grains
a. To get more grains in your diet:
i. Check labels of rolls and bread.
ii. Add brown rice or barley to soups.
iii. Choose whole-grain ready-to-eat cereals.
iv. Have a whole-grain cereal for breakfast.
3. Milk and Milk Products
a. Dairy products provide many nutrients, including calcium, vitamin
D, and potassium, and may improve bone health, lower blood
pressure, and reduce the risk of cardiovascular disease and type 2
diabetes.
b. Dietary Guidelines recommend 3 cups a day for adults – ideally from
no-fat or low-fat dairy products.
4. Protein Sources
a. These include seafood, meat, poultry, eggs, beans and peas, soy
products, and nuts.
b. Dietary Guidelines recommend a balanced variety of protein sources as
well as 8 or more ounces of seafood a week.
5. Oils
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a. Replace some solid fats with oils in order to lower cholesterol and
promote heart health.
6. Nutrients of Concern
a. The Dietary Guidelines also recommend that Americans get adequate
levels of potassium, dietary fiber, vitamin D, vitamin B12, calcium,
iron, and folate.
E. Healthy Eating Patterns
1. A healthy eating pattern is not a rigid prescription but an array of options
that can accommodate cultural, ethnic, traditional, and personal
preferences as well as food costs and availability.
2. My Plate
a. In 2011 the USDA introduced a new food pattern icon that serves as a
visual reminder for healthy eating.
3. The USDA Food Patterns
a. These approaches identify daily amounts of foods to eat from five
major food groups and subgroups.
b. They include a vegan pattern and a lacto-ovo-vegetarian pattern.
4. The DASH Eating Plan
a. Emphasizes vegetables, fruits, low-fat milk and milk products;
includes whole grains, poultry, seafood, and nuts; and is lower in
sodium, red and processed meats, sweets, and sugar-containing
beverages.
5. The Mediterranean Diet
a. Emphasizes vegetables, fruits and nuts, olive oil, and grains with only
a small amount of meats and full-fat milk and milk products.
6. Vegetarian Diets
a. Lacto-ovo-pesco-vegetarians eat dairy products, eggs, and fish but not
red meat.
b. Lacto-vegetarians eat dairy products as well as grains, fruits and
vegetables.
c. Ovo-lacto-vegetarians also eat eggs.
d. Vegans or pure vegetarians eat only plant foods.
e. Vegetarians need to understand the concept of complementary
proteins to get sufficient protein in their diet.
f. Vegetarian diets have proven health benefits including lower
cholesterol levels, healthier weight, decreased risk of heart disease,
and lower incidences of breast, colon, and prostate cancer; high blood
pressure; and osteoporosis.
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III. The Way We Eat
A. Campus Cuisine: How College Students Eat
1. Often on their own for the first time, college students typically change
their usual eating patterns.
2. Students make meal choices based first on price, convenience, and then
nutrition.
3. The proportion of 18- to 24-year-olds that eats the recommended amounts
of fruits and vegetables is generally lower than in the population as a
whole.
4. Time pressures often affect students’ food choices.
B. Fast Food: Nutrition on the Run
1. Young adults consume approximately 40 percent of their daily calories
away from home and eat at fast-food restaurants an average of two to
three times a week.
2. Many fast foods are high in calories, sugar, salt, and fat and low in
beneficial nutrients.
C. His Plate, Her Plate: Gender and Nutrition
1. Men and women do not need to eat different foods, but their nutritional
needs are different.
a. Men:
i. Consume more calories
ii. Should cut back on fat and meat in their diets
b. Women:
i. Should increase their iron intake by eating meat
ii. Should consume more calcium-rich foods, including low-fat and
nonfat dairy products, leafy greens, and tofu
iii. Who become pregnant should take a multivitamin with 400
micrograms of folic acid
D. You Are What You Drink
1. “Enriched” or “fortified” water is not necessarily better.
2. Soft Drinks
a. Soda consumption has decreased among young adults, although one
in five still qualify as heavy users.
b. The health dangers associated with sweetened drinks include
increased calorie intake, higher body weight, lower consumption of
calcium and other nutrients, and greater risk of medical problems,
such as diabetes.
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3. Energy Drinks
a. Although many students use caffeine-fueled concoctions for a
physical or mental edge, there is little scientific evidence to indicate
that they provide any benefit.
b. Some energy drinks contain 15 time the amount of caffeine in a 12-
ounce of cola.
c. Doctors recommend that all adults limit their caffeine intake to 500
mg a day.
IV. Taking Charge of What You Eat
A. Introduction
1. The Nutrition Labeling and Education Act requires food manufacturers to
provide information about fat, calories, and ingredients in large type on
packaged food labels, and they must show how a food item fits into a
daily diet of 2,000 calories.
2. The law also restricts nutritional claims for terms such as healthy, low-fat,
and high-fiber.
B. Portions and Servings
1. A food-label serving is a specific amount of food that contains the quantity
of nutrients described on the Nutrition Facts label.
2. A portion is the amount of a specific food that an individual eats at one
time.
3. According to nutritionists, “marketplace portions” or the actual amounts
served to customers are two to eight times larger than the standard
serving sizes defined by the USDA.
C. Nutrition Labels
1. The Nutrition Facts label, required on food packages for 20 years, focuses
on those nutrients most clearly associated with disease risk and health.
2. The most recent changes proposed by the FDA include:
a. Information about the amount of “added sugars” or empty calories in
a food product.
b. Updated serving size requirements to reflect the amounts people
actually eat, not what they “should” be eating.
c. Calorie and nutrition information for both “per serving” and “per
package” calorie for larger packages that could be consumed in one
sitting or multiple sittings.
d. Inclusion of potassium and vitamin D, nutrients that some in the U.S.
population need more of. Vitamins A and C are no longer required on
the label.
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e. Revised Daily Values (the total amount of a nutrient that the average
adult should aim to get or not exceed on a daily basis) for a variety of
nutrients such as sodium, dietary fiber, and vitamin D to help
consumers understand the nutrition information in the context of a
total daily diet.
D. What is Organic?
1. Foods certified as organic by the USDA must meet strict criteria,
including:
a. Processing or preservation only with substances approved by the
USDA for organic foods.
b. Processing without genetic modification or ionizing radiation.
c. No use of most synthetic chemicals, such as pesticides, herbicides, or
fertilizers.
d. Fertilization without sewage sludge.
e. Food-producing animals grown without medication such as
antibiotics or hormones, provided with living conditions similar to
their natural habitat, and fed with organic food.
2. There has been little research as to whether organic foods are nutritionally
superior to conventional foods.
E. Choosing Healthful Snacks
1. Food manufacturers are offering “better-for-you” options that are lower in
salt and sugar or free of trans fat and artificial colors.
2. A best-for-you option is fruit.
V. Food Safety
1. Foodborne infections cause an estimated 76 million illnesses, 325,000
hospitalizations, and 5,000 deaths in the United States every year.
2. Salmonella, Listeria, and Toxoplasma are responsible for more than 75
percent of these deaths.
B. Fight BAC!
1. Four key culprits in foodborne illness:
a. Improper cooling
b. Improper hand washing
c. Inadequate cooking
d. Failure to avoid cross-contamination
C. Avoiding E. coli Infection
1. Eating unwashed produce, such as spinach or lettuce, or undercooked
beef, especially hamburger, can increase your risk of infection with
Escherichia coli (E. coli) bacteria.
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D. Food Poisoning
1. Salmonella
a. A bacterium that contaminates many foods, particularly undercooked
chicken, eggs, and sometimes processed meats.
2. Campylobacter jejuni
a. A bacterium found in water, milk, and some foods.
b. Campylobacter poisoning can lead to severe diarrhea and has been
implicated in the growth of stomach ulcers.
3. Staphylococcus aureus
a. When cooked foods are cross-contaminated with the bacteria from
raw foods and not stored properly, staph infections can result,
causing nausea and abdominal pain.
4. Clostridium botulinum
a. Improper home canning can cause botulism, an uncommon but
sometimes fatal form of food poisoning.
5. Listeria
a. Bacteria commonly found in deli meats, hot dogs, soft cheeses, raw
meat, and unpasteurized milk.
E. Pesticides
1. Commercial pesticides save billions of dollars of valuable crops from
pests, but they also may endanger human health and life.
2. Fearful of potential risks in pesticides, many consumers are purchasing
organic foods.
F. Food Allergies
1. The National Institute of Allergy and Infectious Diseases define a food
allergy as “an adverse health effect arising from a specific immune
response that occurs reproducibly on exposure to a given food.”
2. As many as 50 to 90 percent of presumed food allergies are not allergic
reactions.
3. Cow’s milk, eggs, seafood, wheat, soybeans, nuts, seeds, and chocolate
have all been identified as common triggers of food allergies.
VI. Nutritional Quackery
A. The AND describes nutritional quackery as a growing problem for
unsuspecting consumers.
B. If the promises of a nutritional claim sound too good to be true, they probably
are.
C. Almost anyone can claim to be a nutritionist.