Transcript Slide 1

Outline:
1.Nutrients
2.Balancing the Diet
3.Nutrient Analysis
4.Nutrient
Supplementation
5.Energy Substrates for
Physical Activity
6.Nutrition for Athletes
7.Bone Health &
Osteoporosis
8.2005 Dietary
Guidelines for Americans
9.Proper Nutrition: A
Lifetime Prescription for
Healthy Living
Chapter 3
Nutrition for
Wellness
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Nutrition for Wellness
• Nutrition: Science that studies the
relationship of foods to optimal health and
performance
• Substrates: Substances acted upon by an
enzyme (carbohydrates, fats)
• Nutrients: Substances found in food that
provide energy, regulate metabolism, and
help with growth and repair of body
tissues
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Nutrition for Wellness
• A person’s diet should supply all of the
essential nutrients for healthy body
functioning, and provide enough
substrates to produce energy for everyday
activities
• Nutrients should be obtained from a wide
variety of sources
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MyPyramid: Steps to a healthier you
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Nutrition for Wellness
• Too much or too little of any nutrient can
cause serious health problems
• U.S. diet too high in calories, sugar,
saturated fat, trans fat, sodium
• Too low in grains, fruits, vegetables
• Diet and nutrition play a role in the
development and progression of heart
disease, cancer, obesity, diabetes, and
osteoporosis
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Nutrients
• Carbohydrates, fat, and protein are fuel
nutrients because they are the only
substances the body uses to supply
energy needed (calories) for work and
normal body functions
• Vitamins, minerals, and water are
regulatory nutrients because they are
required for a person to function normally
and maintain good health
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Nutrients
• Nutrient density is a measure of the
amount of nutrients and calories in various
foods
• Calorie is the amount of heat necessary
to raise the temperature of water 1 degree
Centigrade; used to measure the energy
value of food and cost (energy
expenditure) of physical activity
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Carbohydrates
• Major source of energy (4 calories/gram)
• Regulate fat and metabolize protein
• Major sources are breads, cereals, fruits,
vegetables, milk/dairy products
• Two types:
– Simple
– Complex
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Major types of carbohydrates
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Simple Carbohydrates
• Often called “sugars,” which have little
nutritive value
• Examples are candy, soda, and cakes
• Divided into monosaccharides and
disaccharides
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Complex Carbohydrates
• Also referred to as “polysaccharides”
• Carbohydrates formed by ten or more
monosaccharide molecules linked together
• Examples are: starches, dextrins,
glycogen
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Fiber
• Form of complex carbohydrate
• Present mainly in plant leaves, skins,
roots, and seeds
• Processing and refining foods removes
most of their natural fiber
• Dietary sources include
– Whole-grain cereals and breads
– Fruits and vegetables
– Legumes
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Fiber
• Lack of fiber has been linked to
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Cardiovascular disease
Cancer
Constipation
Diverticulitis
Hemorrhoids
Gallbladder disease
Obesity
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High-fiber foods are essential in a
healthy diet
• Age 50 and under
– Women = 25 g/day
– Men = 38 g/day
• Over age 50
– Women = 21 g/day
– Men = 30 g/day
• Current average daily
U.S. intake
– About 15 g/day
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Fiber
• Eat more fruits, vegetables, legumes,
whole grains, and whole-grain cereals to
increase dietary fiber
• Increasing fiber intake to 30 g/day
significantly reduces heart attacks, colon
cancer, beast cancer, diabetes, and
diverticulitis
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Fat
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Also called lipids
Source of energy (9 calories/gram)
Part of cell structure
Stored energy
Insulator for body heat preservation
Shock absorption
Supplies essential fatty acids
Carries fat-soluble vitamins (A, D, E, K)
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Chemical structure of saturated and
unsaturated fats
Saturated Fats
• Meats, animal fat, lard,
whole milk, cream, butter,
cheese, ice cream,
hydrogenated oils, coconut
oil, and palm oils
• Usually do not melt at
room temperature
• Coconut oil and palm oils
are exceptions
• Raise blood cholesterol
level
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Unsaturated Fats
• Usually liquid at room temperature
• Help lower blood cholesterol
• Monounsaturated fats (MUFAS) are
found in olive, canola, peanut, sesame
oils, avocados, cashews, and peanuts
• Polyunsaturated fats (PUFAS) are
found in corn, cottonseed, safflower,
walnut, sunflower, soybean oils, and fish,
almonds, pecans
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Trans Fatty Acids
• Solidified fat formed by adding hydrogen
to monounsaturated and polyunsaturated
fats to increase shelf life
• Margarine and spreads, shortening, some
nut butters, crackers, cookies, dairy
products, meats, processed foods, and
fast foods
• These products carry a health risk greater
than saturated fat
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Proteins
• Build and repair tissue
• Part of hormones, antibodies, and enzymes
(formed by proteins)
• Necessary for normal functioning
• Help maintain normal body fluid balance
• Source of energy (4 calories/gram) if
carbohydrate is insufficient
• Sources are meats and alternatives, milk, and
other dairy products
• Excess proteins can be converted to glucose or
fat, or excreted in urine
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Protein
• Proteins that contain all of the essential
amino acids known as “complete” or
“high-quality” protein are of animal origin
• Proteins missing one or more of the
essential amino acids are known as
“incomplete” or “lower-quality” protein
• Too much “complete” protein in the diet is
linked to heart disease and cancer
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Vitamins
• Organic nutrients essential for normal
metabolism, growth, and development
• Classified according to solubility
– Fat soluble (A, D, E, and K)
– Water soluble (B complex and C)
• Most vitamins must be obtained through
diet
• A, D, and K are formed in the body
• C, E, and beta-carotene are “antioxidants”
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Minerals
• Inorganic nutrients essential for normal
body functions
• Part of all cells
• Help maintain water balance and acidbase balance
• Essential components of enzymes
• Regulate muscular and nervous tissue
impulses, blood clotting, normal heart
rhythms
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Water
• Most important nutrient
• Involved in digesting and absorbing food,
producing energy, circulatory process,
regulating body heat, removing waste
products, building cells, transporting
nutrients
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Approximate proportions of nutrients
in the human body
• Men have a greater
percentage of total
body weight in water
due to a higher
amount of muscle
mass
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Water
• People get enough water from liquids and
solid foods
• People stay hydrated by allowing thirst to
be their guide
• Exercise in the heat requires regular
hydration prior to thirst or dehydration can
occur
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Nutrition Standards
• Dietary Reference Intakes (DRIs): A
general term that describes four types of
nutrient standards that establish adequate
amounts and maximum safe nutrient
intakes in the diet; these standards are
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Estimated Average Requirements (EAR)
Recommended Dietary Allowances (RDA)
Adequate Intakes (AI)
Tolerable Upper Intake Levels (UL)
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Nutrition Standards
• Estimated Average Requirements
(EAR): The amount of a nutrient that
meets the dietary needs of half the people
in the U.S.
• Recommended Dietary Allowances
(RDA): The daily amount of a nutrient
(statistically determined from the EARs)
considered adequate to meet the known
nutrient needs of almost 98% of all
healthy people in the U.S.
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Nutrition Standards
• Adequate Intakes (AI): The
recommended amount of a nutrient intake
when sufficient evidence is not available to
calculate the EAR and subsequent RDA
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Nutrition Standards
• Tolerable Upper Intake Level (UL): The
highest level of nutrient intake that appears safe
for most healthy people, beyond which exists an
increased risk of adverse effects
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Nutrition Standards
• Daily Values (DVs): Reference values for
nutrients and food components used in
food labels
• Include fat, saturated fat, and
carbohydrates as a percent of total
calories
• Include cholesterol, sodium, and
potassium in milligrams
• Include fiber and protein in grams
• Based on a 2,000-calorie diet
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Food Label with U.S. Recommended Daily Values
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Nutrient Analysis
• First step in evaluating the diet
• Most people do not realize how harmful and nonnutritious many common foods are
• Analysis covers calories, carbohydrates, fats,
cholesterol, and sodium
• Also covers eight crucial nutrients: protein,
calcium, iron, vitamin A, thiamin, riboflavin,
niacin, and vitamin C
• If the regular diet has enough of these eight
nutrients, foods consumed in natural form
typically contain all the other nutrients needed
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Caloric value of food (fuel nutrients)
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Computation for fat content in food
• Each gram of fat
provides 9 calories
• Follow the equation at
the bottom of the
label to determine the
percentage of fat
calories of individual
foods
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Vegetarianism
• Five Basic Types of Vegetarians
– Vegans: eat no animal products at all
– Ovovegetarians: allow eggs in the diet
– Lactovegetarians: allow foods from the milk
group
– Ovolactovegetarians: include egg and milk
products in the diet
– Semivegetarians: do not eat red meat, but
do include fish and poultry, milk products, and
eggs in their diet
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Nutrient Supplements
• Half of all adults in U.S. take daily nutrient
supplements
• Nutrient requirements for body normally
can be met by consuming 1,200 calories
per day, as long as the diet contains the
recommended servings from the five food
groups
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Antioxidants
• Vitamin E: found in oil-rich seeds and
vegetable oils
• Supplements should be taken with a meal
that contains some fat as vitamin E is fat
soluble
• Almonds, hazelnuts, peanuts, canola oil,
safflower oil, cottonseed oil, kale,
sunflower seeds, shrimp, wheat germ,
sweet potato, avocado, and tomato sauce
are high in vitamin E
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Antioxidants
• Vitamin C may offer benefits against
heart disease, cancer, and cataracts
• Water-soluble
• Body eliminates it in about 12 hours
• Consume vitamin C-rich foods twice a day
for best results
• Body absorbs little vitamin C beyond the
first 200 mg
• Oranges, citrus fruit, bell peppers, kale,
cauliflower, tomatoes, strawberries
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Antioxidants
• Beta-carotene recommended dose is
20,000 IU from food sources
• Research found supplements do not offer
protection against heart disease, cancer,
nor offer other benefits
• One medium raw carrot provides about
20,000 IU
• Can be obtained from sweet potatoes,
pumpkin, cantaloupe, squash, kale,
broccoli, tomatoes, peaches, apricots
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Vitamin D
• Research suggests vitamin D has anticancer properties, decreases
inflammation, strengthens the immune
system, controls blood pressure, helps
maintain muscular strength, may help
deter diabetes and fight depression
• Required for calcium absorption
• Research indicates that vitamin D levels at
the time of cancer onset improve survival
rates
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Vitamin D
• Sunshine is the best source
• UV rays lead to the production of vitamin D3
which is transformed by the liver and kidneys
into vitamin D
• Strive for daily “safe sun” exposure, or 15
minutes of unprotected sun on the face, arms,
hands between 10 a.m. and 4 p.m. a few times a
week
• The body generates only what it needs
• 2,000 IU D3 supplements with limited sun
exposure
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Side Effects
• Toxic effects from antioxidant
supplementation are rare if taken under
the ULs
• Check with a physician should side effects
occur when taking vitamin E, vitamin C,
selenium
• Pregnant women need doctor’s approval
prior to beta-carotene supplementation
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GM Foods
• Genetically modified foods (GM
foods): Foods whose basic genetic
material (DNA) is manipulated by inserting
genes with desirable traits from one plant,
animal, or microorganism into another one
to either introduce new traits or enhance
existing ones
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GM Foods
• Crops are genetically modified to make
them resist disease and extreme
environmental conditions, require less
fertilizers and pesticides, last longer, and
to improve nutrient content and taste
• GM foods could help save billions of dollars
in more productive crops and help feed
the hungry in developing countries around
the world
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GM Foods
• Concerns over the safety of GM foods
have created heated public debates
– Genetic modifications may create “transgenic”
organisms that have not previously existed
and that have potentially unpredictable effects
on the environment and on humans
– GM foods may cause illness or allergies in
humans and crosspollination may destroy
other plants or create “superweeds” with
herbicide-resistant genes
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Energy Substrates for Physical
Activity
• Glucose (sugar) and fat (fatty acids) are
the two main fuel supplies for energy
during physical activity
• Amino acids are used for energy when
glucose is low from fasting, prolonged
aerobic exercise, or a low-carbohydrate
diet
• Glucose is stored as glycogen in the
muscles and liver
• Fatty acids are stored in the body as fat to
be used during exercise
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Contributions of the energy formation mechanisms
during various forms of physical activity
• Energy derived from
food is first
transformed into ATP
or adenosine
triphosphate
• The breakdown of ATP
provides energy used
by all energy-requiring
processes of the body
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Energy (ATP) Production
• ATP can be resynthesized in three ways:
– ATP-CP (high-energy phosphate compound)
stored in the body to use during all-out
activities lasting 1-10 seconds
– Anaerobic/lactic acid system breaks down
glucose to create ATP without oxygen for
maximal-intensity exercise sustained for 10
seconds to 3 minutes
– Aerobic system produces ATP using glucose,
fatty acids, and oxygen for steady-state
exercise
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Nutrition for Athletes
• The main difference between the diets of a
sedentary person and a highly active
person is the total caloric and
carbohydrate intake needed during
prolonged physical activity
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Fluid and carbohydrate replenishment during exercise is
essential when participating in long-distance aerobic
endurance events, such as a marathon or a triathlon
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Fluid & Carbohydrate Intake
during Long-Distance Events
• Consume 30 to 60 grams of carbohydrates
per hour
• Best accomplished by drinking 8 ounces of
a sports drink containing 6% to 8%
carbohydrate every 15 minutes
• Fluid intake lessens the chance of
dehydration
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2005 Dietary Guidelines for
Americans
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Proper Nutrition: A Lifetime
Prescription for Healthy Living
• Three factors that do
the most for health,
longevity and quality
of life are proper
nutrition, a sound
exercise program,
quitting/never starting
smoking
• If parents adopt a
healthy diet, children
will follow
© 2010 Cengage-Wadsworth