Learn all about Vitamin B3 (Niacin)

Vitamin B3 functions primarily as a precursor to nicotinamide adenine dinucleotide (NAD) and its phosphate form (NADP), critical coenzymes involved in over 400 biochemical reactions. These coenzymes facilitate electron transfer in energy metabolism, allowing cells to convert carbohydrates, fats, and proteins into ATP (energy). Niacin also participates in non-redox reactions involving DNA repair and cell signalling. In pharmacological doses, nicotinic acid specifically inhibits diacylglycerol acyltransferase-2 in the liver, reducing triglyceride synthesis and consequently decreasing production of very low-density lipoproteins (VLDL), which eventually leads to lower LDL cholesterol. The characteristic 'niacin flush' occurs when nicotinic acid activates GPR109A receptors in skin cells, triggering prostaglandin release and subsequent vasodilation. In skin care, nicotinamide supports barrier function, reduces inflammation, and regulates sebum production through its roles in cellular energy production and antioxidant protection.

Vitamin B3 occurs naturally in a wide variety of foods, with animal products generally providing the most bioavailable forms. Particularly rich sources include poultry (especially chicken breast and turkey), beef, and liver, which provide both ready-made niacin and the amino acid tryptophan that can be converted to niacin in the body. Fish such as tuna, salmon, and mackerel offer excellent niacin content. Plant-based sources are more variable but include peanuts, brown rice, mushrooms (especially portobello and shiitake varieties), and whole wheat products. Some breakfast cereals and flour products are fortified with niacin due to its historical importance in preventing pellagra. The body can also synthesise niacin from dietary tryptophan, though this conversion is relatively inefficient, requiring approximately 60mg of tryptophan to produce 1mg of niacin.