Vitamin B3 (Niacin and Metabolite) – 070115

Niacin (nicotinic acid) is a water-soluble vitamin that is also referred to as vitamin B₃.^1,2Nicotinamide (nicotinic acid amide) is the derivative of niacin that is incorporated into the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).^1-3 The nicotinamide moiety of NAD and NADP serves as an electron acceptor or donor in biological oxidation-reduction (redox) reactions catalyzed by several hundred different enzymes. NAD serves as the cofactor for enzymes that break down (catabolize) carbohydrates, fats, proteins, and alcohol while NADP supports biosynthetic (anabolic) reactions, including the synthesis of all macromolecules, such as fatty acids and cholesterol.^1,2 Nicotinamide has also been shown to serve as a cofactor in adenosine diphosphate (ADP)-ribose transfer reactions that play an integral part in deoxyribonucleic acid (DNA) repair calcium mobilization.^3,4 Studies of cultured cells and animal models suggest that ADP-ribose polymer-mediated DNA repair and cyclic ADP-ribose-mediated cell-signaling pathway may play a role in cancer prevention.^3,4