This document discusses the water soluble vitamin niacin. It begins by providing background on niacin, including its chemical name and that it acts as a co-enzyme in cells. The document then explains that the active forms of niacin are NAD+ and NADP+, which are formed when niacin attaches to ribose phosphate and adenosine monophosphate. The document also discusses diseases related to niacin deficiency like pellagra and its symptoms. Finally, it covers dietary sources of niacin and the recommended daily intake.