What Are Vitamins & What Do They Do?

Most people know that vitamins are "good" for them, but that may be the extent they know about vitamins. Whether you take a single multivitamin, several individual vitamins or take no vitamins at all and get your nutrients from food, you should become familiar with what vitamins are and what they can do for you. Talk to your doctor before adding vitamin supplements to your diet.

General

Vitamins are a substances that are essential for your body and provide normal cellular function, growth and development. There are 13 of these essential vitamins: vitamins A, C, D, E, K and the B vitamins: thiamine, riboflavin, niacin, pantothenic acid, biotin, folate, vitamin B-6 and vitamin B-12. You can obtain most these vitamins from the foods you eat.

Vitamin Functions

The vitamin B family helps you get energy from the foods you eat. Vitamins A, C and E are antioxidants which protect your cells from oxygen damage and scavenge "free-radicals" that can damage your cells. Vitamin A also supports your eyesight. Vitamin D supports optimal bone health. Vitamin K is necessary for proper blood clotting. In general, vitamins support health and your normal physical and cognitive function.

Vitamin Supplements

One out of every two Americans takes multivitamins, according to Harvard Medical School, although you don't need a multivitamin if you eat a balanced diet full of fruits, vegetables, nuts, whole grains and fish. A multivitamin will have little effect on your body if you are already getting what you need, reports Harvard.The exception may be fish oil dietary supplements which may lower your risk of heart disease and other cardiovascular ailments.

Recommended Dietary Allowances

Your recommended dietary allowance is a specific measurement of how much of a vitamin you need on a daily basis to avoid a deficiency. Not every vitamin has an RDA established. Among the major vitamins, the RDA for vitamin D for both men and women is 5 to 10 mcg daily. Men require 10 mg and women require 8 mg of vitamin E. Men should get 70 to 80 mcg of vitamin K and women need 60 to 65 mcg of vitamin K daily. For vitamin C, men require 90 mg and women require 75 mg.

Vitamin Side Effects

Although vitamins are associated with a healthful lifestyle and optimal body function, there are potential side effects. Taking large amounts of fat-soluble vitamins beyond your dietary requirement is ineffective and can be toxic. For example, taking too much vitamin A may lead to liver damage and birth defects if you are pregnant. Fat-soluble vitamins such as A, D, E and K can reach toxic levels because these vitamins are stored in your body fat and are not quickly eliminated from your body like water-soluble vitamins such as vitamin C or the B vitamins.