Vitamin B6

This article is about the group of vitamers. For the dietary supplement, see Pyridoxine.

Vitamin B6
Drug class
The chemical structure of pyridoxal phosphate, a form of vitamin B6.
Pyridoxal 5'-phosphate, the metabolically active form of vitamin B6
Class identifiers
UseVitamin B6 deficiency
ATC codeA11H
Biological targetenzyme cofactor
Clinical data
Drugs.comInternational Drug Names
External links
MeSHD025101
Legal status
In Wikidata

Vitamin B6 is one of the B vitamins, and is an essential nutrient for humans.[1][2][3][4] The term essential nutrient refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosphate, serves as a coenzyme in more than 140 enzyme reactions in amino acid, glucose, and lipid metabolism.[1][2][3]

Plants synthesize pyridoxine as a means of protection from the UV-B radiation found in sunlight[5] and for the role it plays in the synthesis of chlorophyll.[6] Animals cannot synthesize any of the various forms of the vitamin, and hence must obtain it via diet, either of plants, or of other animals. There is some absorption of the vitamin produced by intestinal bacteria, but this is not sufficient to meet dietary needs. For adult humans, recommendations from various countries' food regulatory agencies are in the range of 1.0 to 2.0 milligrams (mg) per day. These same agencies also recognize ill effects from intakes that are too high, and so set safe upper limits, ranging from as low as 25 mg/day to as high as 100 mg/day depending on the country. Beef, pork, fowl and fish are generally good sources; dairy, eggs, mollusks and crustaceans also contain vitamin B6, but at lower levels. There is enough in a wide variety of plant foods so that a vegetarian or vegan diet does not put consumers at risk for deficiency.[7]

Dietary deficiency is rare. Classic clinical symptoms include rash and inflammation around the mouth and eyes, plus neurological effects that include drowsiness and peripheral neuropathy affecting sensory and motor nerves in the hands and feet. In addition to dietary shortfall, deficiency can be the result of anti-vitamin drugs. There are also rare genetic defects that can trigger vitamin B6 deficiency-dependent epileptic seizures in infants. These are responsive to pyridoxal 5'-phosphate therapy.[8]

  1. ^ a b "Facts about Vitamin B6 Fact Sheet for Health Professionals". Office of Dietary Supplements at National Institutes of Health. February 24, 2020. Archived from the original on April 18, 2011. Retrieved February 5, 2021.
  2. ^ a b "Vitamin B6". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, OR. May 2014. Archived from the original on March 14, 2018. Retrieved March 7, 2017.
  3. ^ a b Cite error: The named reference PKIN2020B6 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference DRItext was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Havaux2009 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Parra2018 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Schorgg2021 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Ghatge2021 was invoked but never defined (see the help page).