Necesary food nutrients in diet.
Carbohydrates
Carbohydrates are the body's main source of energy. There are three different kinds of carbohydrates. They include starch, sugar, and fiber. Starch is made from chains of small sugars. When these chains are broken down during digestion, we get energy. We get 4 calories from each gram of starch (or sugar). We do not get calories from fiber because our bodies do not break fiber down during digestion.
Plant foods like cereals, bread, rice, pasta, potatoes, plantains and corn are good sources of starch. They give us the energy we need to do daily activities. These starchy foods give us important vitamins and minerals, too.
Because carbohydrate-rich foods are usually low in calories, they can help us keep a healthy weight. When we add fat (like butter, sour cream or gravies) at the table or when we cook , we add extra calories and may gain weight. Try using less mayonnaise, butter or margarine on breads and muffins. Use less gravy or sour cream on potatoes. When we shop we can get the carbohydrates we need without added fat by reading food labels. Compare crackers and bread products and try the ones with less fat. Use more vegetables without fatty sauces.
Fat
Fat is a nutrient that is an important source of calories. One gram of fat supplies 9 calories - more than twice the amount we get from carbohydrates or protein. Fat also is needed to carry and store essential fat-soluble vitamins, like vitamins A and D. There are two basic types of fat. They are grouped by their chemical structure. Each type of fat is used differently in our bodies and has a different effect on our health.
When we eat a lot of high fat foods, we get a lot of calories. With too many calories, we may gain weight. Eating too much fat may also increase the risk of getting diseases like cancer, heart disease, high blood pressure or stroke. Health experts recommend that we should get no more than 30% of our calories from fat to reduce our risk of getting these diseases.
Fat is found in many foods. Some of the fat that we eat comes from the fat we add in cooking or spread on breads, vegetables or other foods. A lot of fat is hidden in foods that we eat as snacks, pastries or prepared meals.
We can reduce the amount of fat we eat by cutting down on the fat that we add in cooking or spread on foods. We can eat skim milk and low fat cheeses instead of whole milk and cheese. We can also use less fat, oil, butter, and margarine. Another way to cut down on fat is to drain and trim meats and take the skin off poultry. We can also read labels and compare the amount of fat in foods to make lower fat choices.
Protein
Most all the parts of our bodies are made from protein: hair, skin, blood, organs, and muscles. It is needed for cells to grow. It also repairs or replaces healthy cells and tissues. Protein in food gives us calories - 4 calories in one gram. If we do not get enough calories from fat and carbohydrates we may use protein for energy. Most Americans, even athletes, get the protein they need without using special foods, powders or shakes.
Protein is made of chains of amino acids. Amino acids are the building blocks of protein. Our bodies can make most amino acids. There are a few amino acids that we cannot make; so, we must get them from the foods we eat. They are known as "essential amino acids." Most foods that come from animals, such as fish, chicken, beef, pork, eggs, milk, cheese, and yogurt contain all of the essential amino acids. They are known as "complete" proteins. Plant foods, such as rice, dried beans, peas, lentils, nuts, seeds, wheat, oats, corn, may be low or lacking in one or more of the amino acids. They are considered to be incomplete proteins. Incomplete proteins can be mixed together to make a complete protein.
Fat-Soluble Vitamins
Small amounts of vitamins A, D, E and K are needed to
maintain good health.
Foods that contain these vitamins will not lose them
when cooked.
The body does not need these every day and stores them
in the liver when not used.
Most people do not need vitamin supplements.
Megadoses of vitamins A, D, E or K can be toxic and
lead to health problems.
Vitamins are essential nutrients your body needs in
small amounts for various roles in the human body. Vitamins are divided into
two groups: water-soluble (B-complex and C) and fat-soluble (A, D, E and K).
Unlike water-soluble vitamins that need regular replacement in the body,
fat-soluble vitamins are stored in the liver and fatty tissues, and are
eliminated much more slowly than water-soluble vitamins.
Because fat-soluble vitamins are stored for long
periods, they generally pose a greater risk for toxicity than water-soluble
vitamins when consumed in excess. Eating a normal, well-balanced diet will not
lead to toxicity in otherwise healthy individuals. However, taking vitamin
supplements that contain mega doses of vitamins A, D, E and K may lead to
toxicity. Remember, the body only needs small amounts of any vitamin.
While diseases caused by a lack of fat-soluble
vitamins are rare in the United States, symptoms of mild deficiency can develop
without adequate amounts of vitamins in the diet. Additionally, some health
problems may decrease the absorption of fat, and in turn, decrease the
absorption of vitamins A, D, E and K.
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Table 1: Vitamin facts.
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Vitamin
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Source
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Physiological Functions
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Deficiency
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Overconsumption
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A (retinol) (provitamin A, such as beta carotene)
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Vitamin A: liver, vitamin A fortified milk and dairy
products, butter, whole milk, cheese, egg yolk.
Provitamin A: carrots, leafy green vegetables, sweet potatoes, pumpkins, winter squash, apricots, cantaloupe. |
Helps to form skin and mucous membranes and keep
them healthy, thus increasing resistance to infections; essential for night
vision; promotes bones and tooth development. Beta carotene is an antioxidant
and may protect against cancer.
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Mild: night blindness, diarrhea, intestinal
infections, impaired vision.
Severe: inflammation of eyes, keratinization of skin and eyes. Blindness in children. |
Mild: nausea, irritability, blurred vision.
Severe: growth retardation, enlargement of liver and spleen, loss of hair, bone pain, increased pressure in skull, skin changes. |
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D
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Vitamin D-fortified dairy products, fortified
margarine, fish oils, egg yolk. Synthesized by sunlight action on skin.
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Promotes hardening of bones and teeth, increases the
absorption of calcium.
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Severe: rickets in children; osteomalacia in adults.
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Mild: nausea, weight loss, irritability.
Severe: mental and physical growth retardation, kidney damage, movement of calcium from bones into soft tissues. |
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E
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Vegetable oil, margarine, butter, shortening, green
and leafy vegetables, wheat germ, whole grain products, nuts, egg yolk,
liver.
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Protects vitamins A and C and fatty acids; prevents
damage to cell membranes. Antioxidant.
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Almost impossible to produce without starvation;
possible anemia in low birth-weight infants.
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Nontoxic under normal conditions.
Severe: nausea, digestive tract disorders. |
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K
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Dark green leafy vegetables, liver; also made by
bacteria in the intestine.
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Helps blood to clot.
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Excessive bleeding.
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None reported.
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Water-Soluble
Vitamins
B-complex vitamins and vitamin C are water-soluble
vitamins that are not stored in the body and must be replaced each day.
These vitamins are easily destroyed or washed out
during food storage and preparation.
The B-complex group is found in a variety of foods:
cereal grains, meat, poultry, eggs, fish, milk, legumes and fresh vegetables.
Citrus fruits are good sources of vitamin C.
Use of megadoses of vitamins is not recommended.
Vitamins are essential nutrients found in foods. The
requirements are small but they perform specific and vital functions essential
for maintaining health.
The two types of vitamins are classified by the
materials in which they will dissolve. Fat-soluble vitamins -- vitamins A, D, E
and K -- dissolve in fat before they are absorbed in the blood stream to carry
out their functions. Excesses of these vitamins are stored in the liver.
Because they are stored, they are not needed every day in the diet.
By contrast, water-soluble vitamins dissolve in water
and are not stored; they are eliminated in urine. We need a continuous supply
of them in our diets. The water-soluble vitamins are the B-complex group and
vitamin C.
Water-soluble vitamins are easily destroyed or washed
out during food storage or preparation. Proper storage and preparation of food
can minimize vitamin loss. To reduce vitamin loss, refrigerate fresh produce,
keep milk and grains away from strong light, and use the cooking water from
vegetables to prepare soups.
Vitamin B-Complex
Eight of the water-soluble vitamins are known as the
B-complex group: thiamin (vitamin B1), riboflavin (vitamin B2),
niacin, vitamin B6, folate, vitamin B12, biotin and
pantothenic acid. These vitamins are widely distributed in foods. (See Table
2.) Their influence is felt in many parts of the body. They function as
coenzymes that help the body obtain energy from food. They also are important
for normal appetite, good vision, healthy skin, healthy nervous system and red
blood cell formation.
Vitamin C
Why do we need vitamin C? Like the other vitamins, the
body needs vitamin C to keep it in good working order. Also known as ascorbic
acid, vitamin C helps hold body cells together, aids in wound healing, assists
in bone and tooth formation, strengthens the blood vessel walls, is vital for
the function of the immune system, and improves absorption and utilization of
iron. It also helps prevent nutritional ailments such as scurvy, the disease
that did the most to bring public attention to vitamin deficiency diseases.
Our bodies cannot make vitamin C. Therefore, every day
we must eat foods containing this vitamin. Although the body has a constant
need for vitamin C, it has a limited storage capacity. A regular and adequate
intake is essential.
Some conditions have been shown to increase vitamin C
requirements. They are:
- environmental stress,
- use of certain drugs (such as oral contraceptives),
- tissue healing of wounds,
- growth (children and pregnant women),
- fever and infection, and
- smoking.
The controversy over use vitamin C to prevent or cure
the common cold and other disorders has not been resolved. Vitamin supplements
will not necessarily provide extra energy, clear up skin problems, or prevent
and cure the common cold, heart disease, and cancer. Unlike pellagra, beriberi,
or scurvy, these problems are not the result of a vitamin deficiency. What is
known is that the only disease a vitamin will cure is the one caused by a
deficiency of that vitamin.
Vitamin C also serves as an antioxidant. It works with
vitamin E as a free-radical scavenger. Studies suggest that vitamin C may
reduce the risk of certain cancers, heart disease and cataracts. Research
continues to document the degree of these effects.
Fiber is one kind of carbohydrate. It is sometimes called roughage or bulk. Fiber is the part of plant foods that our bodies do not break down during digestion. Because fiber isn't digested, it doesn't give us calories. Foods that contain a lot of fiber may also contain other types of carbohydrates like starch or sugar. While we do not get calories from the fiber in these foods, we do get calories from the sugars and starches they contain.
Fiber is important for keeping the digestive tract working smoothly. Since we do not digest it, the fiber in food passes into the intestine and absorbs water. The undigested fiber creates "bulk" so the muscles in the intestine can push waste out of the body. Eating enough fiber helps prevent constipation. It may also reduce the risk of getting colon cancer. Some fibers can help lower blood cholesterol.
Dried peas and beans like lentils, black-eyed peas, chickpeas and kidney beans are the best sources of fiber. The skins and seeds in fresh fruits and vegetables are good sources, too. Whole-grain cereals and breads like oatmeal, brown rice, grits and whole-wheat bread are all naturally high in fiber.
Often the fiber in plant foods (like skins, bran or seeds) is removed when the food is cooked by us or processed by the manufacturer. We get more fiber when we eat whole fruits and vegetables with the peels and seeds than we do when we eat foods like applesauce or instant mashed potatoes. When we shop we can look on food labels to find products that say "100%" whole grain. We can also compare the Nutrition Facts to find foods with more fiber.
Water
The human body is two-thirds water. Water is an
essential nutrient that is involved in every function of the body.- Water helps transport nutrients and waste
products in and out of cells.
- Water is necessary for all digestive, absorption,
circulatory, and excretory functions
- Water is needed for the utilization of the
water-soluble vitamins.
- It is needed for the maintenance of proper body
temperature.
Minerals
Minerals are essential for body functioning and structure. They help to build
body tissues (e.g. bone) or to regulate metabolic activities.
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