What is the primary function of niacin in the body?

Niacin, also known as vitamin B3, plays a crucial role in the body primarily through its function in redox reactions. It serves as a precursor to the coenzymes nicotinamide adenine dinucleotide (NAD) and its phosphate form (NADP). These coenzymes are vital for numerous biochemical reactions, particularly those involved in cellular energy production and metabolism.

Through its role as NAD and NADP, niacin participates in oxidation-reduction processes, which are fundamental in metabolic pathways including glycolysis, the Krebs cycle, and fatty acid synthesis. This function is essential for the conversion of carbohydrates, fats, and proteins into energy, thereby supporting overall metabolic homeostasis.

While niacin is indirectly associated with fat metabolism, protein synthesis, and bone health, its primary and most critical role is within the redox reactions that drive various physiological processes. Therefore, understanding niacin's central involvement in these reactions clarifies its necessity for optimal metabolic function and energy production.