Niacin’s role in the body is extensive, primarily because it forms part of essential coenzymes like NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate). These coenzymes participate in over 200 metabolic pathways, including the production and breakdown of carbohydrates, fatty acids, and amino acids. Niacin is also involved in vasodilation, or blood vessel widening, which supports blood flow and may help reduce blood pressure. A deficiency in niacin can lead to pellagra, a disease characterized by diarrhea, dermatitis, dementia, and, if untreated, can be fatal.
Historically, pellagra was linked to corn-based diets, especially after the introduction of maize to Europe in the 1770s. Corn lacks bioavailable niacin, which led to widespread cases of pellagra until the link was confirmed in 1937 by American scientist Joseph Goldberger. Although pellagra is rare in industrialized countries today, cases may still occur, particularly in alcoholics, where it can manifest mainly as encephalopathy, a brain disorder.
Niacin is not only obtained from dietary sources but can also be synthesized by the body from the amino acid tryptophan, with the help of vitamin B2 (riboflavin). The Recommended Dietary Allowance (RDA) for adults ranges from 13 to 20 mg per day, with increased requirements in pregnancy, lactation, and periods of active physical work. Children need between 5 to 16 mg daily. Dietary sources include meats, poultry, fish, nuts, peanuts, and enriched or whole grain products.
In grains, niacin exists in a bound form known as niacytin, attached to small peptides and carbohydrates, making it less bioavailable. Nonetheless, with the widespread availability of niacin-rich foods, severe deficiencies have become rare, underscoring the success of fortification and dietary awareness in maintaining adequate niacin levels for health.
Niacin: A Vital B Vitamin for Health and Metabolism
