Water Soluble Vitamins

B complex vitamins (including thiamin, riboflavin, niacin, vitamin B6, pantothenic acid, biotin, folic acid, vitamin B12), and vitamin C are usually referred to as water-soluble vitamins. However, their solubility in water is the only characteristic that they share. Because of this general characteristic, these vitamins are easily absorbed by simple diffusion and do not require the presence of fat or bile acids for their absorption.

The discoveries of the water-soluble vitamins began at the turn of the last century with the recognition by Christian Eijkman, a Dutch physician, that rice bran contained a factor that prevented beriberi in certain animals. The factor was called water-soluble B factor. Another water-soluble factor, which prevented scurvy, was discovered later, and named vitamin C. By this time, it was clear that water-soluble B was not a single factor but a group of biologically active factors with similar physical properties and food sources. Collectively, these factors became known as the 'B complex'.

Water-soluble vitamins have their own unique set of characteristics. Each of the B vitamins contains nitrogen, which is lacking in vitamin C and other fat-soluble vitamins.

Most of the water-soluble vitamins function as essential coenzymes or cofactors of enzymes involved in various aspects of metabolism. A cofactor or coenzyme is a small molecule that associates closely with enzymes and facilitates their functioning. As vital coenzymes, vitamin B is required for normal growth, nerve and brain function, reproduction and almost every cellular reaction in the body.

It is true that without B vitamins, the body would lack energy. However, vitamins do not provide the body with fuel for energy. The energy yielding nutrients are carbohydrates, fats and proteins. B vitamins help the body to use that fuel. Several of the B vitamins - thiamin, riboflavin, niacin, pantothenic acid and biotin - form part of the coenzymes that enable enzymes to release energy from carbohydrates, fats, and proteins. Other B vitamins also play indispensable roles in metabolism. Vitamin B6 assists enzymes that metabolize amino acids (basic unit of proteins), and folic acid, and B12 help cells to multiply.

Since the water-soluble vitamins are not stored the body for more than a few days, daily or frequent consumption is imperative. On the same account, they rarely accumulate in amounts that can an cause toxicity. Since the water-soluble vitamins simultaneously exist in the food sources, rarely will your body be deficient of only one of the B vitamins; usually the deficiency is of two or three of them.