What Is the General Function of Vitamins?

Vitamins are organic compounds necessary for the functioning of body systems, nerves, muscles, skin and bone. An organic compound is called a vitamin when it cannot be produced by the organism that needs it, making it a dietary requirement. In all, the body needs 13 vitamins, with each one having a specific function.

Thirteen Essential Vitamins

The body needs 13 essential vitamins in order to achieve and maintain optimal growth, development and repair. These vitamins include vitamins A, C, D, E, K and the group of B vitamins referred to as B complex. It consists of vitamins B-1, B-2 and B-3 or thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B-6 or pyridoxine, and vitamin B-12. Vitamins are either fat-soluble or water-soluble. The human body can produce vitamin D and biotin, but supplementation may be needed to meet nutritional needs.


An antioxidant inhibits the chemical reaction that produces free radicals, which are atoms, molecules or ions with an unpaired electron. These free radicals create a chain reaction that damages cells, which can ultimately lead to disease. Vitamins E and C function as antioxidants.

Energy, Maintenance and Repair

B complex vitamins function as precursors for enzymes, which act as catalysts in metabolism, which involves binding to a protein, which is often an enzyme. This process transforms the nutrients from your diet into substances the body can use to for energy, maintenance and repair. Biotin, for example, is essential for the production of fatty acids. Folic acid is also necessary for cell growth, production and development.

Absorption of Minerals

Most vitamins are needed for your body to use minerals. You need vitamin D so your body can absorb and use calcium and phosphate. Vitamin C is essential for the absorption of iron and its incorporation into haemoglobin in the red blood cells, which is critical for the absorption and transport of oxygen.

Absorption of Vitamins

Minerals are also required to enable vitamins to function properly. Zinc releases vitamin A from the liver, and is also necessary for the absorption of folic acid. Calcium is needed for the absorption of vitamin B-12, which is produced in the stomach. Zinc and vitamin B-6 work together in the production of brain transmitters. Magnesium and vitamin B-6 combine to prevent kidney-stone formation. Manganese is needed by intestinal bacteria for the synthesis of vitamin K, which controls blood clotting.

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About the Author

Based in Atlanta, Valerie Liles has been writing about landscape and garden design since 1980. As a registered respiratory therapist, she also has experience in family health, nutrition and pediatric and adult asthma managment. Liles holds a Bachelor of Arts in journalism from Colorado State University and a Master of Science in technical communication from the University of Colorado.