Vitamins are chemical compounds that are essential for normal growth and metabolism; you need them to keep healthy.

The main role of vitamins is to help convert the food you eat into energy and living tissues such as bones, muscles, blood, nerves and skin – without them, you would fall apart! Vitamins also help the body resist infection and protect body cells. Although vitamins are essential to life, they are only required in tiny amounts. 

Because vitamins cannot be made by the body (except vitamin D), you have to get them from food. Most vitamins are not stored in the body to any great extent and must be replenished regularly, which is why it’s so important to eat a well-balanced diet.

New research also suggests a greater role for vitamins (and minerals) in the prevention or slowing down of many diseases such as heart disease, cancer, cataracts, osteoporosis and birth defects. The total effects of vitamins on the body are still not fully known or understood.

There are two broad groups of vitamins:

• Fat-soluble vitamins including vitamins A, D, E, K, and beta-carotene
• Water-soluble vitamins including the B vitamins, (B1, B2, B3, B6, B12) vitamin C, and folate.

Vitamin supplements can be useful for people who cannot obtain sufficient amounts from food – perhaps as a result of illness or special dietary requirements.

However, there are many other nutritional factors with vitamin-like qualities that can only be obtained by eating a wide variety of foods. Vitamin supplements are not a substitute for a healthy diet.

Large doses of vitamins or minerals can also have drug-like effects and should only be taken under medical supervision.

RDAs are the amounts of essential nutrients that are considered adequate to meet the nutritional requirements of healthy people. They are designed to prevent nutritional deficiency diseases such as scurvy, beriberi, pellagra, rickets and anemia. Following RDA recommendations for vitamins and other nutrients helps keep your body in good health.

However, it’s important to remember that the RDAs do not address the extra nutrient needs of people who have certain chronic ailments, who smoke, or who are on prescribed medication. 

To find out RDAs for specific vitamins, click on the related article links at the end of this article.