Vitamin B3

This article is about a class of chemically related vitamers sometimes called niacin. For other uses, see Niacin (disambiguation).

Vitamin B3
Drug class
Structure of nicotinamide, one of the vitamers of vitamin B3
Class identifiers
UseVitamin B3 deficiency
ATC codeA11H
Biological targetenzyme cofactor
Clinical data
Drugs.comNiacin
External links
MeSHD009536
Legal status
In Wikidata

Vitamin B3, colloquially referred to as niacin, is a vitamin family that includes three forms, or vitamers: niacin (nicotinic acid), nicotinamide (niacinamide), and nicotinamide riboside.[1] All three forms of vitamin B3 are converted within the body to nicotinamide adenine dinucleotide (NAD).[1] NAD is required for human life and people are unable to make it within their bodies without either vitamin B3 or tryptophan.[1] Nicotinamide riboside was identified as a form of vitamin B3 in 2004.[2][1]

Niacin (the nutrient) can be manufactured by plants and animals from the amino acid tryptophan.[3] Niacin is obtained in the diet from a variety of whole and processed foods, with highest contents in fortified packaged foods, meat, poultry, red fish such as tuna and salmon, lesser amounts in nuts, legumes and seeds.[4][5] Niacin as a dietary supplement is used to treat pellagra, a disease caused by niacin deficiency. Signs and symptoms of pellagra include skin and mouth lesions, anemia, headaches, and tiredness.[6] Many countries mandate its addition to wheat flour or other food grains, thereby reducing the risk of pellagra.[4][7]

The amide nicotinamide (niacinamide) is a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP+). Although niacin and nicotinamide are identical in their vitamin activity, nicotinamide does not have the same pharmacological, lipid-modifying effects or side effects as niacin, i.e., when niacin takes on the -amide group, it does not reduce cholesterol nor cause flushing.[8][9] Nicotinamide is recommended as a treatment for niacin deficiency because it can be administered in remedial amounts without causing the flushing, considered an adverse effect.[10] In the past, the group was loosely referred to as vitamin B3 complex.[11]

  1. ^ a b c d Stipanuk MH, Caudill MA (2013). Biochemical, Physiological, and Molecular Aspects of Human Nutrition - E-Book. Elsevier Health Sciences. p. 541. ISBN 9780323266956. Vitamin B3... potentially includes three different molecular forms: nicotinic acid, niacinamide, and nicotinamide riboside
  2. ^ Bieganowski P, Brenner C (May 14, 2004). "Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a Preiss-Handler independent route to NAD+ in fungi and humans". Cell. 117 (4): 495–502. doi:10.1016/s0092-8674(04)00416-7. PMID 15137942.
  3. ^ Cite error: The named reference DRItext was invoked but never defined (see the help page).
  4. ^ a b "Niacin". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, OR. October 8, 2018. Retrieved September 16, 2019.
  5. ^ "Niacin Fact Sheet for Health Professionals". Office of Dietary Supplements, US National Institutes of Health. June 3, 2020. Retrieved June 29, 2020.
  6. ^ Hegyi J, Schwartz RA, Hegyi V (January 2004). "Pellagra: dermatitis, dementia, and diarrhea". International Journal of Dermatology. 43 (1): 1–5. doi:10.1111/j.1365-4632.2004.01959.x. PMID 14693013. S2CID 33877664.
  7. ^ "Why fortify?". Food Fortification Initiative. 2017. Archived from the original on April 4, 2017. Retrieved April 4, 2017.
  8. ^ Jaconello P (October 1992). "Niacin versus niacinamide". CMAJ. 147 (7): 990. PMC 1336277. PMID 1393911.
  9. ^ Kirkland JB (May 2012). "Niacin requirements for genomic stability". Mutation Research. 733 (1–2): 14–20. doi:10.1016/j.mrfmmm.2011.11.008. PMID 22138132.
  10. ^ Cite error: The named reference Pellagra And Its Prevention was invoked but never defined (see the help page).
  11. ^ Silvestre R, Torrado E (2018). Metabolic Interaction in Infection. Springer. p. 364. ISBN 9783319749327. Niacin or nicotinate, together with its amide form nicotinamide, defines the group of vitamin B3 complex