Vitamins are a group of substances essential for normal cell function, growth and development.
There are 13 essential vitamins. That means they are needed for the body to function.
They are:
Vitamin A
Vitamin C
Vitamin D
Vitamin E
Vitamin K
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin)
Pantothenic acid
Biotin
Vitamin B6
Vitamin B12
Folate (folic acid)
Vitamins are grouped into two categories:
Fat-soluble vitamins are stored in the body's fatty tissue.
Water-soluble vitamins must be used by the body right away. Any left over water-soluble vitamins leave the body through the urine. Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years.
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Function
Each vitamin has specific functions. You can develop health problems (deficiency disease) if you do not get enough of a particular vitamin.
Vitamin A helps in the formation and maintenance of healthy teeth, bones, soft tissue, mucous membranes, and skin.
Vitamin B6 is also known as pyridoxine. The more protein a person eats, the more vitamin B6 is needed to help the body use the protein. Vitamin B6 helps form red blood cells and maintain brain function, among other things.
Vitamin B12, like the other B vitamins, is important for metabolism. It also helps form red blood cells and maintain the central nervous system.
Vitamin C, also called ascorbic acid, is an antioxidant that promotes healthy teeth and gums. It helps the body absorb iron and maintain healthy tissue. It also promotes wound healing.
Vitamin D is also known as the "sunshine vitamin," since it is made by the body after being in the sun. Ten to 15 minutes of sunshine three times per week is enough to produce the body's requirement of vitamin D. This vitamin promotes the body's absorption of calcium, which is essential for the normal development and maintenance of healthy teeth and bones. It also helps maintain proper blood levels of calcium and phosphorus.
Vitamin E is an antioxidant also known as tocopherol. It plays a role in the formation of red blood cells and helps the body use vitamin K.
Vitamin K is not listed among the essential vitamins, but without it blood would not stick together (coagulate). Some studies suggest that it helps promote strong bones in the elderly.
Biotin is essential for the metabolism of proteins and carbohydrates, and in the production of hormones and cholesterol.
Niacin is a B vitamin that helps maintain healthy skin and nerves. It is also has cholesterol-lowering effects.
Folate works with vitamin B12 to help form red blood cells. It is necessary for the production of DNA, which controls tissue growth and cell function. Any woman who is pregnant should be sure to get enough folate. Low levels of folate are linked to birth defects such as spina bifida. Many foods are now fortified with folic acid.
Pantothenic acid is essential for the metabolism of food. It is also plays a role in the production of hormones and cholesterol.
Riboflavin (B2) works with the other B vitamins. It is important for body growth and the production of red blood cells.
Thiamine (B1) helps the body cells change carbohydrates into energy. It is also essential for heart function and healthy nerve cells. Back to Top
Food Sources
FAT-SOLUBLE VITAMINS
Vitamin A:
Eggs
Meat
Milk
Cheese
Cream
Liver
Kidney
Cod
Halibut fish oil
Vitamin D:
Cheese
Butter
Margarine
Cream
Fortified milk
Fish
Oysters
Cereals
Vitamin E:
Wheat germ
Corn
Nuts
Seeds
Olives
Spinach and other green leafy vegetables
Asparagus
Vegetable oils and products made from vegetable oils, such as margarine
Vitamin K:
Cabbage
Cauliflower
Spinach
Soybeans
Cereals
WATER-SOLUBLE VITAMINS
Folate:
Green, leafy vegetables
Fortified foods
Niacin (B3):
Dairy products
Poultry
Fish
Lean meats
Nuts
Eggs
Legumes
Enriched breads and cereals
Pantothenic acid and biotin
Eggs
Fish
Dairy products
Whole-grain cereals
Legumes
Yeast
Broccoli and other vegetables in the cabbage family
White and sweet potatoes
Lean beef
Thiamine (B1):
Fortified breads, cereals, and pasta
Whole grains
Lean meats
Fish
Dried beans
Peas
Soybeans
Dairy products
Fruits and vegetables
Vitamin B12:
Meat
Eggs
Poultry
Shellfish
Milk and milk products
Vitamin C (ascorbic acid)
Citrus fruits and juices
Strawberries
Tomatoes
Broccoli
Turnip and other greens
Sweet and white potatoes
Cantaloupe
Most other fruits and vegetables contain some vitamin C; fish and milk contain small amounts.
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Side Effects
Many people think that if some is good, a lot is better. This is not always the case. High doses of certain vitamins can be poisonous. Ask your doctor what is best for you.
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Recommendations
The Food and Nutrition Board at the Institute of Medicine establish recommended dietary allowances (RDAs) for vitamins. The recommendations reflect how much of each nutrient you should receive on a daily basis, based on the known nutritional needs of practically all healthy people.
The best way to get the daily requirement of essential vitamins is to eat a
balanced diet that contains a variety of foods from the
food guide pyramid.
Specific recommendations for each vitamin depend on age, gender, and other factors (such as pregnancy).
More Information on This Topic
Background Carotenoids Phytochemicals Healthy Foods Dietary Health Benefits References News & Features
Review Date: 1/2/2007
Reviewed By: William McGee, M.D., M.H.A., Assistant Professor of Medicine and Surgery, Tufts University School of Medicine, Boston, MA, and Chairman, Nutrition Committee, Baystate Medical Center, Springfield, MA. Review provided by VeriMed Healthcare Network.A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).
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