This essential B-group vitamin is thought to be necessary for normal red blood cell formation and contributes to the normal function of the immune system. Vitamin B also helps in the release of energy from the foods we eat. Vitamin B12 is a member of the B-Complex group of vitamins and is most commonly found in animal products including meat and fish. Therefore, vegetarians and vegans may benefit highly from this supplement, as they are most likely to be deficient of this vitamin.