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Part Four Your Health and Nutrition
Selecting a healthful combination of foods
requires a basic understanding of nutrients.
Nutrients are the chemical substances in food
that are used. by your body to keep it going.
They are needed to promote growth and
development, provide energy, and regulate
body functions.
Six types of nutrients are needed to nourish
your body and keep it working properly.
The six types of nutrients are proteins,
carbohydrates, fats, vitamins, minerals, and
water. No one food contains all the nutrients'
needed for nourishing the body. You need to
eat a variety of foods to get all the nutrients
you need.
Proteins
16=2 Exercise and eating right can help keep
you healthy and allow you to do the activities
you enjoy.
will help you develop to the fullest possible
extent. Good health as an adult will help you be successful in what ever you choose to do.
You may have heard the expression "You
are what you eat." This means eating a poor
combination of foods could lead to poor health.
Likewise, eating a healthful combination of
foods will help keep you healthy.
Your skin, hair, nails, muscles, blood, and
all other body tissues contain protein. Proteins
are needed for growth, maintenance, and repair
of tissues. Proteins are also needed to control
body processes, such as blood circulation,
breathing, and digestion. Proteins act as a
source of energy, too.
Proteins are made of amino acids. Amino
acids can be thought of as chains of blocks.
They are used by your body to build the type of
protein it needs.
The body can make some amino acids.
Others, called essential amino acids, cannot
be made by the body. They must be obtained
through foods.
Meat, fish, poultry, cheese, eggs, milk, dry
beans, peas, nuts, and seeds are all food sources
of protein. Protein foods fall into two main
groups. The protein from animal food sources
is called complete protein. Complete protein
supplies all the essential ammo acids your body
needs, 16-3. The protein from plant food sources
is called incomplete protein. Incomplete protein
supplies only some of the essential amino acids.
People who do not eat enough protein-rich
foods may grow more slowly. They may also
develop infections more easily and recover
from illnesses at a slower rate. You can see why
eating protein foods each day is important.
R'esource: What Does the Body Need? transparency master 16-2, TR.
nutrients that nourish the body and keep it working properly.
Resource
Discuss: What protein foods did you eat today? How can these help
your body?
i=nri,.,h·
Nutrients, Activity B, SAG.
~",*,a bulletin board illustrating
various foods that contain
Chapter 16 Nutrition and You
Carbohydrates
Carbohydrates are nutrients that give your
body its main source of energy for physical
activities. If enough carbohydrates are not
eaten to supply the energy you need, the
body uses energy from proteins. This makes
carbohydrates an important nutrient since
proteins should be saved for the job of building
and repairing tissµes.
Three types of carbohydrates are sugars,
starches, and fiber. Sugars can be used by your
body as a quick source of energy. Starches take
longer for your body to use as an energy source.
Fiber does not supply your body with energy.
Instead, it aids in digestion by helping push
foods through the body at the proper speed.
Candy, jelly, honey, milk, and frosting are
food sources of sugars. Starches, along with
sugars, are found in foods such as fruits,
vegetables, breads, cereals, pasta, dry beans,
and nuts. Fruits, vegetables, whole grains, and
bran are food sources of fiber.
The amount of carbohydrates needed each
day depends on a person's activities. Eating
more carbohydrates than you need could
cause you to gain weight. This is because your
body stores starch and sugar you do not need
for energy as fat. If you do not eat enough
carbohydrates, you may feel tired. You could
also have digestive problems if you do not eat
enough fiber. Remember that because your
body needs energy, you need carbohydrates.
Fats
16=g Foods from animals, such as this roast
beef, are sources of complete proteins. They
supply all of the essential amino acids your
body needs.
Enrich: Research the role of carbohydrates in the diets of athletes.
Activity: Bring various magazine articles to class that promote various
types of diets. Analyze these diets and determine whether or not they are
nutritionally sound.
Fats are concentrated sources of energy
from animals or plants. They are needed to
keep your body functioning efficiently. They
carry some needed vitamins throughout your
system. They insulate and protect vital organs'
such as your heart, liver, and kidneys. Fat also
forms a layer just under your skin that protects
your body from cold temperatures.
Part Four Your Health and Nutrition
You get fats from foods such as butter,
margarine, meats, cheeses, salad dressings, and
many snack and dessert foods, 16-4. Although
you need to eat some fat, many people eat too
much fat. This may cause weight gain or other
health problems. Many experts agree that
you should limit the amount of fat you eat.
You can limit your intake of fat by choosing
low-fat dairy products and lean meats (meats
containing very little fat). Avoiding too many
fried foods is another way you can limit the
amount of fat you eat.
Many high-fat foods are also high in
cholesteroL Cholesterol is a fatlike substance
found in every human celL It is an essential
part of blood and certain hormones. Cholesterol
in the diet comes from animal food sources.
Health authorities link too much cholesterol in
the diet with heart disease. They recommend
you limit dietary cholesterol to reduce your risk
of health problems.
Vitamins
Vitamins are substances needed by the
body for growth and maintenance. Vitamins
help regulate the chemical processes in your
body. They also help your body store and use
energy for growth and development. Although
required in very small amounts, vitamins are
essential to life and health.
You should try to eat foods that provide
you with all the vitamins you need. Then you
will not need to take vitamin pills to meet your
daily requirements.
Vitamins are either fat-soluble or watersoluble. Fat-soluble vitmnins are carried through
your body by fats. The fat-soluble vitamins are
vitamins A, D, E, and K.
Fat-soluble vitamins can be stored by your
body. Therefore, you do not need to eat food
sources of them every day. In fact, getting more
than the required amounts of these vitamins
could be dangerous. This is because your body
can store them in levels that could make you
sick. If you eat foods containing these vitamins,
there is no reason to take pills containing them
in extra amounts.
Water-soluble vitamins dissolve in water.
This causes unused amounts of these vitamins
to leave your body along with body wastes.
Water-soluble vitamins cannot be stored in
your body, so you need to eat foods that supply
these vitamins every day. Vitamin C and the B
vitamins are water-soluble.
You should be aware of the main vitamins
and what they do for your body. You also
need to know what foods supply each of these
vitamins. This knowledge will help you choose
foods that make your body look and feel its best.
Vitamin A
16=4 You need to be aware of fats in foods
you eat, especially in snacks and desserts.
Enrich: Research current information about dietary cholesterol and its
link with heart disease.
Discuss:
Are vitamin supplements necessary if you eat a balanced diet?
Vitamin A works to keep your skin in good
condition. If your skin is dry and rough, you
may need some of this important vitamin.
Note: An orange coloring to the skin can result if you consume excess
amounts of carotene.
Chapter 16 Nutrition and You
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Problem of
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D~ficiencies
Why aren't people getting enough vitamins in
their diets?
Do you think there are certain situations
in which people should take vitamin
Vitamin A is also necessary for normal vision.
Without it, your eyes cannot adjust to bright
light or darkness as well.
Because vitamin A is fat-soluble, it can be
stored by your body. However, you still need a
good source of it at least every other day.
Many deep yellow and dark green .
vegetables and fruits are good sources of
vitamin A. Such vegetable and fruit sources
include carrots, broccoli, spinach, cantaloupe,
peaches, and apricots, 16-5. These brightly
colored vegetables and fruits contain a
substance called carotene. This substance can be
changed into vitamin A by your body.
Vitamin A is also found in the fatty parts
of animal products. Butter, cream, cheeses,
egg yolks, and liver provide good sources of
vitaminA.
The B Vitamins
The B vitamins are a group of vitamins
that work together in your body. Three key B
vitamins are thiamin (vitamin B-1), riboflavin
(vitamin B-2), and niacin (vitamin B-3). These
vitamins help your body release energy from
food. They promote growth, appetite, and
digestion. They help keep your nervous system
healthy and prevent irritability. They also keep
skin healthy.
The B vitamins are water-soluble so you
need to include them in your diet every day.
Luckily, getting daily sources of B vitamins is
easy because they can be found in many foods.
Foods rich in B vitamins include whole
- grains and enriched breads and cereals. Leafy
green vegetables, legumes, meat, milk, and eggs
are also good sources.
Vitamin C
Vitamin C helps produce a substance
that holds body cells together. Through this
function, vitamin C plays an important role
in your body. It helps broken bones mend
and wounds heaL It strengthens the walls of
blood vessels. Vitamin C also helps your body
use some other nutrients. It helps you resist
infections and maintain healthy gums, skin,
and teeth.
Vitamin C is water-soluble and is not stored
in the body. Therefore, you need at least one
good source of vitamin C each day to keep this
vitamin in your body.'
Vitamin C is found in many fruits and
vegetables. Citrus fruits, such as oranges and
grapefruit, are great sources. Cantaloupe,
strawberries, broccoli, and tomatoes are also
good sources of this vitamin.
Vitamin
16=5 Peaches
are just one of many food
sources of vitamin A.
Enrich: Folic acid is an additional B vitamin. Research current
information about this vitamin in relation to its role in preventing birth
defects.
D
Vitamin D helps your body use the minerals
that are needed to build bones and teeth. This
function is especially important during periods
Discuss: What are your favorite sources of vitamin C?
Discuss: What is a nonfood source of viiamin D?
Part Four Your Health and Nutrition
when your body is growing rapidly. Periods
of rapid growth occur during childhood and
adolescence.
Vitamin D is sometimes called "the
sunshine vitamin." This is because your body
can make vitamin D when exposed to sunlight.
Besides the sun, another source of vitamin D is
fortified milk, 16-6. Fortified means nutrients
have been added to the food product. Fish liver
oil and some fish are other good sources of
vitamin D.
.
Vitamin E
Vitamin E is believed to keep oxygen in
the body from destroying other nutrients,
especially vitamin A. So many foods contain
vitamin E that people rarely suffer from
deficiencies, or shortages. Some important
sources are vegetable oils, whole grain breads
and cereals, eggs, organ meats, and leafy green
vegetables.
Vitamin K
Vitamin K helps blood clot. As with vitamin E,
many foods contain vitamin K so deficiencies
are rare. Some important sources are green
leafy vegetables, cauliflower, liver, and egg yolk.
Minerals
_ Minerals are another type of nutrient
needed for a healthy body. Minerals help
regulate many of your body's activities. They
help muscles contract and nerves transmit
signals to and from the brain. They also
help maintain the body's water balance and
strengthen bones and teeth.
Although there are many minerals known
to be needed, the most well known are calcium,
phosphorus, chlorine, potassium, and sodium.
Also included are the trace minerals iron,
. iodine, and fluorine. Trace minerals are'
minerals that are found in only small amounts
in the body.
Calcium and Phosphorus
Calcium and phosphorus are two minerals
that work together as a team. Both are more
effective when the other is present. They are
both needed for strong bones and teeth. They
are also important for clotting of blood and for
normal heart and muscle formation.
The richest food sources of calcium are milk
and milk products, including yogurt and hard
cheeses. Other good sources are fish and green,
leafy vegetables. Foods that are rich in calcium
are also good sources of phosphorus.
16-6
Milk is often fortified to provide you with
vitamin D.
Resource:
Nutrient Sources, transparency master 16-2, TR.
Vocabulary:
What does clotting mean in relation to blood?
Activity:
Make a chmt listing minerals and their sources.
Reflect: How many sources of calcium and phosphorus did you eat
today?
Chapter 16 Nutrition and You
Sodium, Chlorine,
and Potassium
Sodium, chlorine, and potassium work together
in your body. They help keep the right amount
of fluid around and inside the cells in your
body. They allow the cells to take up nutrients
from the blood. These minerals also help nerves
and muscles function as they should.
These minerals are found in many foods.
Table salt is a source of sodium and chlorine.
Potassium is plentiful in bananas, orange juice,
green leafy vegetables, and milk.
Many people eat more sodium than they
need for good nutrition. Excess sodium is
usually removed from the body as waste.
However, some people have a problem with
sodium staying in the body.
Sodium has been linked to high blood
pressure. For patients with this health problem,
doctors may prescribe a low-sodium diet.
Many foods are available that would conform
with this type of diet. These foods have been
processed with little or no salt and may be
labeled as "low-sodium" or "salt-free."
Iron
Iron is important for healthy red blood cells.
Lack of iron may cause anemia. A person who
has anemia may feel tired, lack energy, and
sense a loss of appetite.
Eating enough foods that contain iron is
especially important for females because they
lose iron during monthly menstrual periods.
Liver is an excellent source of iron. Other
sources are meat, fish, eggs, dried beans and
peas, and whole grain or enriched breads
and cereals.
Iodine is added to iodized salt, 16-7.Most
people use enough salt to meet their needs for
this mineral. Saltwater fish are also a good
source of iodine.
Fluorine
Fluorine is needed for the proper
development of teeth and bones. Scientists have
found that fluorine is useful in the prevention
of tooth decay. Therefore, it is added to many
brands of toothpaste.
Many cities add fluorine to their drinking
water supplies. Small amounts are also found in
meats, milk, and eggs.
Water
Water is the single most important
substance you take into your body. You can get
along for days, even weeks, without food. You
can only survive a few days without water, 16-8.
About two-thirds of your body is made up
of water. Water carries nutrients into cells and
carries wastes out of the body. The food you
eat cannot be digested and used by the body
without an adequate supply of water. Water
also helps regulate the internal temperature of
your body.
Iodine
Iodine is used to help the thyroid gland
produce a hormone that affects growth and
weight. If your body does not receive enough
iodine, the thyroid will get larger in trying to
produce this hormone. This condition is seen
as a swelling at the front of the throat and is
called goiter.
16~7
Iodized salt is the most common source
of the trace mineral iodine.
Enrich: Research current studies about sodium and its link to high blood
pressure.
Discuss: What are good sources of iron that vegetarians may want to
include in their diets?
Discuss: Why is salt often iodized?
Enrich: Find out whether your source of drinking water is fluoridated.