Nicotinamide adenine dinucleotide (NAD+) is a cofactor (a molecule that assists enzymes in chemical reactions) that plays an essential role in multiple physiological processes, such as energy metabolism, DNA repair, and immune activation. It is necessary for the activity of sirtuins, a class of enzymes involved in longevity, and poly-ADP-ribose polymerases (PARPs), a family of DNA-repair enzymes. Cellular NAD+ production declines with age, however, and its depletion likely drives the onset and progression of multiple age-related conditions such as metabolic dysregulation and neurodegenerative disease.
The human body can synthesize NAD+ from a variety of dietary sources, including tryptophan (an amino acid) and the three forms of niacin (vitamin B3) – nicotinamide (NAM, also called niacinamide), nicotinic acid (NA), and nicotinamide riboside (NR) – commonly referred to as niacin equivalents. Of these three, NA is the primary source of NAD+. These precursors are not equally...
