B-12 BASICS: Vitamins are "organic" compounds, which means they are produced naturally in both vegetables and animals and are therefore found in abundant quantities in both of these food sources. The main function of vitamins in the system is to act as "coenzymes" (i.e., substances that enhance the action of proteins which induce chemical reactions). Enzymes are catalysts in all chemical reactions that take place in the body. These reactions include energy metabolism and muscle building, to name only two of thousands. As coenzymes, vitamins are an essential component of enzymatic activity-without vitamins, enzymes simply wouldn't work; you wouldn't build muscle, and your body wouldn't be able to convert the food you eat into all the magnificent chemicals that make up the human body.

Vitamins are either fat-soluble or water-soluble; depending on whether fat or water based molecules transport the vitamin through the bloodstream. Fat-soluble vitamins include A, D, E, and K. Because these vitamins have an affinity for fat, they can be stored in both adipose (fat) tissue and in the liver, extending their functional life span in the body and strongly decreasing the chance of developing deficiencies. The water-soluble vitamins include all of the B vitamins and Vitamin C; they aren't stored in the body for more than a few hours, so daily intake is a must.

HOW TO USE B-12: B 12 belongs to group of B vitamins. The active form of this water-soluble vitamin is not found in vegetable sources. Researchers have found the form in sea vegetables and tofu to be virtually unusable by the body. Only animal-derived foods contain viable amounts of B12. For this reason, many nutritionists advise strict vegetarians to take a B12 supplement.

B12 supplementation (injections especially) is quite popular with bodybuilders who believe it helps boost energy levels, protect the liver, and increase appetite.