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Chapter 5
Nutrition
Mike, 19, what is a balanced diet and how do I
incorporate one into my hectic life?
Questions
What are the essential nutrients, what functions do they
perform, and what are some major sources?
What are the general nutritional guidelines?
Assumptions
Nutrition is vital to wellness
Poor diet is linked to numerous health problems,
including HD, Cancer, Stroke, and Diabetes
A healthy balanced diet in concert with PA
recommendations can help prevent and reverse some of
the disease processes mentioned
I.
Terms
Nutrition: the science of food and how the body
uses it in health and disease
Nutrients: released in the body thru digestion;
provide energy (kilocal), build and maintain body
tissues, and regulate body functions.
Essential Nutrients: substances the body must get
from foods bc of manufacturing deficiencies. Pr,
CHO, Fats, Vitamins, Minerals, and Water are the
essential nutrients. Not all are calorie bearing.
Digestion: The process of breaking down foods in
the GI tract into compounds that the body can absorb
Kilocalorie: A measure of energy content in food; 1
kilocal represents the amount of heat needed to raise
the temp of one liter of water 1 C; “calorie”
II. Components of a Healthy Diet
A. Carbohydrates (4 cals per gram)
An essential nutrient containing C, H, O
Function: supply energy to cells in the brain,
nervous system, and blood; supply energy to
muscles during exercise (high-intensity)
Major Sources: Grains (breads and cereals), fruits,
vegetables, and milk
Recommended Intake: @ 55% of total cals. 15%
from simple CHO and 40% from complex CHO.
Those who regularly engage in strenuous exercise
may need 60-70% bc it can increase the amount of
stored glycogen.
Two groups of CHO:
1. Simple: contain only one (monosaccharides)
or two (disaccharides) sugar units per
molecule. They include most sugars and are
found in fruits, milk, and “sweets”.
2. Complex: consist of chains of sugar
molecules (polysaccharides). Include starches
(found in plants, grains, and legumes) and
dietary fiber (fruits, veg, grains).
During digestion in the mouth and small
intestine, the body breaks down starches and
double sugar molecules into single-sugar
molecules, such as glucose, for abs into the bl.
Cells take glucose and use it for energy. The
liver and muscles take up glucose and store it as
a starch called glycogen. “Glycogen depletion”
Excess CHO are stored as fat.
Unrefined CHO (whole-wheat flour, brown rice,
whole grains) are preferable bc they are digested
more slowly, and may decrease the risk for
obesity, diabetes, and HD.
FIBER: consists of CHO plant substances that are
difficult or impossible to digest.
1. Insoluble Fiber: does not dissolve in water,
making feces bulkier and softer so they pass
more easily through the intestines. Help
prevent constipation and hemorrhoids.
Found in wheat cereals, grains, and vegetables.
2. Soluble Fiber: slows the body’s absorption of
glucose and binds chol containing compounds
in the intestine, lowering bl chol levels.
Thus a diet high in SF can reduce risk of
Diabetes and CVD.
Major Sources: All plant foods contain fiber
but fruits, legumes, oats, and barley are
particularly rich in it. Processing of foods can
remove fiber.
Recommended Intake: 20-35 grams, most
Americans consume @ 16 grams per day
B. Fats ( 9 cals per gram;)
An essential nutrient, typically in the form of
triglycerides (a glycerine molecule plus 3 fatty
acids) in the body.
Function: Supply primary energy during rest/light
activity, insulate, support, and cushion organs;
provide medium for absorption of fat-soluble
vitamins.
The most concentrated energy source.
Major Sources: Sat: meats, dairy products, palm
and coconut oils, hydrogenated vegetable fats;
Unsat: grains, nuts, seeds, fish, and vegetables
Recommended Intake: @ 10-30% of daily cals
with no more than 7-10% coming from sat fat.
You only need about 1 tbls of vegetable oil a day to
supply essential fats.
Linoleic and alpha-linoleic acids are essential.
They maintain BP and play a role in a healthy
pregnancy
Types of Fat: A fatty acid is made up of a chain of
C atoms w/ Ox attached at the end and H atoms
attached along the length of the chain. The degree of
saturation refers to the # of double bonds b/w carbon
atoms on a fatty chain.
1. Saturated: every available bond from each
carbon atom is attached to a hydrogen atom;
no carbon double bonds. Typically solid at
room temp. Found in meats and full-dairy
products.
2. Trans fatty acid: A type of unsat fatty acid
produced during hydrogrenation where many
double bounds are turned into single bonds.
Hydrogenation: hydrogens are added to unsat
fats to increase sat and prolong shelf life.
Found in deep fried foods, baked goods, and
hydroegenated vegetable oils.
1+2 increase LDL-C; a RF for CHD
3. Monounsaturated: only one double bond;
liquid at room temp (reduce LDL-C maintain
HDL-C levels).
4. Polyunsaturated: two or more carbon double
bonds; liquid at room temp; Omega-3 (fish),
linoleic and alpha-linoleic fats
Omega-3 fatty acids may have a + effect on
CV health by reducing the possibility of a
blood clot, decreasing the inflammatory
response in the body, and raising HDL-C
5. Cholesterol: a sterol w/ similar characteristics
as a fat.
* body needs some; aids in proper digestion of F
and is part of cells;but your body provides all
that you need
* chol is only found in animal products; esp in
yolks, organ meat, shellfish etc
C. Protein (4 cals per gram)
An essential nutrient; a compound made up of
amino acids that contain C, H, Ox, and Nitrogen
Function: form important prts of muscles, bone,
blood, enzymes, some hormones, and cell
membranes; repair tissue; regulate water and
acid balance; help in growth; supply energy
Major Sources: Meats, fish, poultry, eggs, milk
products, legumes, and nuts
Recommended Intake: @ 10-15 of total cals.
Many Americans consume more than they need
Amino Acids: the building blocks of Protein.
20 common aa 9 are essential.
Complete Ps: supply all essential aa.
Typically animal Ps
Incomplete Ps: don’t supply all essential aa
Typically plant Ps; Vegetarians can combine
complementing plant P to make a complete P
(wheat bread and peanut butter)
* The best sources of plant P incl dried beans,
peas, grains, seeds, nuts
Amino Acid supplementation:
* free amino acids are not absorbed more readily
than food proteins
* excess protein will not increase muscle mass
(fat or energy)
* RDA recommends .8 grams per kilograms of
body weight. Increase for athletes?
D. Vitamins Carbohydrates (0 cals per gram)
An essential nutrient; Organic substance (carboncontaining) needed in small amounts.
Function: Facilitate chemical reaction w/in cells;
production of red blood cells and maintenance of
nervous, skeletal, and immune systems
Major Sources: Abundant in Grains, fruits,
vegetables; also found in meat and dairy
Recommended Intake:
no wonder vitamin; get thru a variety of foods
Types of vitamins
13 Essential; 9 water-soluble (ex C and B), and 4
fat-soluble (A, D, E, and K)
* Water soluble: absorbed in the blood stream where
they travel freely and are excreted if not needed
* Fat soluble: carried in the blood by special
proteins are stored in body fat rather than excreted.
* Deficiencies: specific characteristics develop
* Excesses: can be harmful (especially fat soluble)
E. Minerals (0 cals per gram)
inorganic (non-carbon containing) compounds
needed in small amounts
Function: Help regulate body functions; aid in the
growth and maintenance of body tissues; act as
catalyst for the release of energy
Major Sources: Found in most food groups
Recommended Intake: There are 17 essential
minerals; if too much or too little are consumed,
problems develop (calcium, iron, sodium)
* categorized as major (need more) or trace (need
less); a few VIP minerals..
Calcium: most abundant mineral in the body; 99% in
the bones, essential for nerve conduction, muscle
contraction, and bl clotting
* W need more
* dairy, fortified juice, bread, green leafy vegetables
Na : water balance, acid-based balance, nerve f(x)
* salt, soy sauce, tomato juice
* most Americans get more than rec; excess can
contribute to high BP
Iron: a trace mineral that is essential for the
transportation and storage of Ox in the blood and
muscles; w/out Ox cells can’t produce energy;
* meat, legumes, eggs, dark green vegetables, dried
fruit, and liver
* W need more (losses in menstruation)
F. Water (0 cals per serving)
most important nutrient; You can live up to 50 days
w/out food and only a couple days w/out water
Function: Makes up 50-70% of body weight; used
in digestion and absorption of food; transports
nutrients; regulates temp; removes waste products
Major Sources: Fruits, vegetables, and liquids
Recommended Intake: at least 8 cups a day! Drink
before you are thirsty!
G. Other substances in food
Phytochemicals: substances found in plant foods that
may prevent some chronic diseases.
* Sulforaphane (in broccoli) helps fight carcinogenic
compounds
Antioxidants: found in many fruits, veg, and tea.
Help rid the body of free radicals (an unstable
electron seeking compound) and protect cells.
III. Nutritional Guidelines
* Moving from a focus on nutritional deficiencies to
overconsumption
* average diet has improved since the 70’s but we
are still getting fatter!
* RDAs (Recommended Daily Allowances) were
developed as standards to prevent deficiencies
* DRIs (Daily Refernce Intakes) developed to
augment the info provided by RDAs
A. General recommendations
1. Eat a variety of foods
2. Balance food intake w/ Physical Act
3. Choose a diet w/ plenty of grains, fruits, veg
4. Choose a diet low in fat, sat fat,+ chol
5. Choose a diet mod in sugars/salt
6. If you choose to drink, do so in moderation
B. Food guide pyramid
* Breads, cereals, pasta, 6-11 servings
ex. ½ bagel =1 serving
Complex carbs, fiber, vitamins and minerals.
Select whole-wheat cereals/pasta, brown rice etc
* Veg grp 3-5 servings
ex. ½ cup chopped raw vegetables
CHO, P, fiber, various vitamins and minerals
* Fruit grp = 2-4 servings
ex. 1 medium size piece; melon wedge
CHO, fiber, vitamins
* Milk, yogurt, cheese 2-3 servings
ex. 1 cup of milk/yogurt
P, CHO, calcium, choose low fat varieties
* Meat, poultry, beans, eggs, nuts, 2-3 s
ex. 2 ½- 3oz cooked lean meat; 3 eggs
P, Iron, watch fat
* Fats, oils, sweets…sparingly
C. Nutrition tips
Eating healthy meals/snacks
* plan…..reduce F, incr grains, fruits/veg
* aim for balance (pyramid)
* simplify food prep as much as possible
* keep the pleasure in eating
D. Eating well while eating out
* Have it your way: gravy on side
* Keep it plain/simple: avoid specialty
* Choose foods that are broiled, grilled, baked,
poached, steamed
* Request milk (1%) /juice vs soda
E. Nutrient supplementation:
eating a well balanced diet (food pyramid) should
supply all necessary vit/min in most people
1. iron deficiency is common in W
* supplementation is frequently rec for women with
heavy menstrual flow (or pregnant/lactating)
* drug users/alcoholics may benefit.... Y
* they don’t improve performance (ergogenic aid)
* supplements are not substitutes for a balanced diet.
F. Vegetarianism:
derive most nutrition from plants…less F and chol
* can be quite healthy; plan
1. Semi V: avoids red meat
2. Lacto-ovo V: excludes all meat, eats eggs/milk…
getting enough iron ?
3. Lacto-veg: excludes all meat/eggs; eats milk
products….iron/zinc?
4. Vegan: excludes all animal foods; eats grains,
legumes, fruits, veg… not rec for preg W,
kids…B-12, calcium, zinc and iron?
VI. Specific Nutrition Considerations
A. Athletes:
In general, athls don’t require special
supplementation, unless diet is deficient. However,
during training more energy (calories) are expended.
2 main fuels that supply energy for physical activity
are glu and fatty acids; not protein!
When exercising below 60-70% HRR fat is used as
primary energy substrate.
As the intensity rises, so does % of glu utilization
B. Special Nutrient needs for Women:
Osteoporosis: the softening, deterioration, or loss of
bone mass
* especially vulnerable after menopause (loss of
estrogen), or with a history of oligomenorrhea
(irregular), or amenorrhea (cessation)
* Estrogen Replacement Therapy is common
*osteoporosis is completely preventable.
maximize bone strength early, minimize bone loss
later.
* normal estrogen levels, adequate Ca+ intake (mod
protein intake), and physical activity
* smoking, excessive alcohol use, and
corticosteroids accelerate the rate of