No, that’s not a misprint or spelling error although spell check doesn’t recognize vitamers. A vitamer of a particular vitamin is any of a number of chemical compounds, generally having a similar molecular structure. All vitamers show vitamin-activity in vitamin-deficiency biological systems, but not necessarily in humans.
Some of these vitamers are familiar to you. For example, Vitamin A has at least six vitamer chemicals that all qualify as “vitamin A”. In the vitamin A family, four of the chemicals naturally found in foods are carotenoids (alpha-carotene, beta-carotene, gamma-carotene and xanthophylls). These chemicals give fruits and vegetables the colors of red, yellow, and orange. Retinols, and retinal forms, found in animal-based foods, are however many times more active in the human body.
Typically, the vitamin activity of multiple vitamers is limited by the body’s ability to convert one vitamer to another, or to add the enzymatic cofactor(s) to make the bioavailable or bio-active form of the vitamin.
Vitamin B12 occurs in foods as cyanocobalamin. When it is absorbed into the epithelial lining of the small intestine, the epithelial cells convert cyanocobalamin to one of two biologically active forms – methylcobalamin or adenosylcobalamin. The cyanide is stripped off of cobalamin and a methyl group or adenosyl group (the enzymatic cofactors) are substituted. The active vitamer is then released into the blood stream to function as vitamin B12.
