Vitamin B12 is a member of the water-soluble B-complex group of vitamins. It is the only vitamin that contains essential mineral elements. B12 is a collective term for a group of cobalt-containing compounds called corrinoids. It includes the free vitamin cyanocobalamin and hydroxocobalamin and two active coenzymes 5-deoxyadenosylcobalamin and methylcobalamin. All B12 compounds are [...]