Vitamin B6

Paper effect bottom

Vitamin B6 is a water-soluble vitamin and is also known as Pyridoxine. Food sources include liver, wheat germ, fish, soya beans, brewer’s yeast, eggs, blackstrap molasses, oats, peanuts and walnuts. The recommended daily amount (RDA) in the UK is 1.4mg for males and 1.2 mg/day for females.

What is it needed for?

Pyridoxine is necessary for the production of red blood cells and hydrochloric acid. It is required in order for the proper absorption of vitamin B12. It is believed to help strengthen the immune system and help prevent certain nerve and skin disorders. Vitamin B6 contributes to the reduction of tiredness and fatigue, the normal functioning of the nervous system and the immune system.

Deficiency

Pyridoxine deficiency is rare in humans however symptoms can be varied and may include skin problems, weakness, irritability, nervousness, mental confusion, susceptibility to noise, weight loss, insomnia, cracking of the lips and tongue, depression and anaemia. Pyridoxine deficiency has also been reported to be associated with immune dysfunction, kidney stones, cancer and carpal tunnel syndrome.

Evidence

Anaemia-Vitamin B6 plays an important role in the production of haemoglobin- the red blood cells that transport oxygen. Anaemia has been shown to be successfully treated with pyridoxine supplementation (1), (2).

Seizures-Seizure activity has been found to be higher in those in deficiency states, which is improved with vitamin B6 (3).

Cardiovascular Health- Alongside B12 and folic acid, vitamin B6 has been shown to support cardiovascular health by lowering homocysteine levels (4) (homocysteine is a naturally occurring protein found in blood plasma, which if present in high amounts may increase the risk of heart disease). The Heart Outcomes Prevention Evaluation 2 trial involving more than 5,500 adults with known cardiovascular disease, showed that supplementing with vitamin B6,  vitamin B12 and folic acid over a period of five years reduced homocysteine levels and decreased stroke risk by about 25% (5). Furthermore, Vitamin B6 specifically has been associated with a reduced risk of developing atherosclerosis by preventing the accumulation of homocysteine, reducing the formation of blood clots and lowering blood pressure (6). It has been reported that individuals with low pyridoxine levels in their blood have a five times greater risk of heart attack compared to those with higher levels (7). 

Immunity- Adequate vitamin B6 status has been shown to be crucial for proper immune function (8). Vitamin  B6 plays an essential role in the utilisation of antibodies and cytokines (small proteins involved in inflammatory and immune reponses). In those deficient in vitamin B6, the reproduction of white blood cells known as lymphocytes which are responsible for fighting infection were reduced. It has also been noted that those low in B6 show a reduction in the amount of antibodies produced in response to immunization (1), (9).

Carpal Tunnel Syndrome- Vitamin B6 deficiency is been found to be common in those who suffer from Carpal Tunnel Syndrome (6). In double blind, placebo controlled studies vitamin B6 supplementation has shown to be successful and effective in treating Carpal Tunnel Syndrome (10), (11), (12). 

Hormones- hormonal activity is reported to be influenced by the action of pyridoxal phosphate (the active form of B6) (13). Vitamin B6 is considered an essential co factor in fatty acid metabolism that impacts upon hormonal health (14).

Depression- Vitamin B6 has been found to be typically low in those suffering with depression according to research, especially those taking birth control pills (15), (16), (17).

Our take on how Vitamin B6 may help you, based upon EU approved claims;

Digestive Support– Vitamin B6 contributes to normal energy-yielding metabolism. Vitamin B6 is required for the correct absorption and metabolism of fats, carbohydrates and proteins, making it valuable for people whose diets are high in these nutrients. It helps support correct growth and development via the correct use of these nutrients.

PMS– Vitamin B6 contributes to the regulation of hormonal activity. This has long been a popular statement with people suffering from the symptoms of PMS. It is most commonly reported to help with symptoms such as mood swings and irritability, which is supported by the claim that Vitamin B6 contributes to normal psychological function.

Anaemia– Vitamin B6 contributes to normal red cell formation. This implies that a B6 deficiency could aggravate anaemia- the result of an iron deficiency. A supplement may therefore help to guard against this.

Safety and side effects

Supplementation of large doses or moderate doses for long periods of time have been associated with unwanted side effects. Symptoms may include severe nerve pain and loss of muscle co- ordination in severe cases. Other symptoms may include painful skin lesions, sensitivity to light, nausea and heartburn. For adults the Tolerable Upper Intake Level has been set at 100mg.

References

  1. Mackey AD, Davis SR, Gregory JF, 2006. Vitamin B6. In: Shils ME, Shike M, Ross AC, Caballero B, and Cousins RJ (eds). Modern Nutrition in health and disease, 10th ed. Baltimore, MD: Lippincott Williams and Wilkins, 194-210.
  2. IoM (Institute of Medicine), 2000. Dietary Reference Intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin and cholin. Washington D.C. National Academy Press
  3. Fernstrom JD and Fernstrom MH, 2005. Brain and nervous system. In: Caballero B, Allen L, Prentice A (eds). Encyclopedia of Human Nutrition. 2nd ed. Elsevier Academic Press, 22
  4. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press; 1998
  5. Saposnik G, Ray JG, Sheridan P, McQueen M, Lonn E. Homocysteine-lowering therapy and stroke risk, severity, and disability: additional findings from the HOPE 2 trial. Stroke 2009;40:1365-72
  6. Murray, M 1996 Encyclopaedia of Nutritional Supplements; Prima Publishing: New York
  7. Kof FJ, et al., Low Vitamin B6 status in patients with acute myocardial infarction. Am J Cardiol 63, 513-6, 1989; Robinson K et al., Hyperhomocysteinemia and low pyridoxal phosphate. Circulation 92, 2825-2830, 1995
  8. RANJIT KUMAR CHANDRA  LEELA SUDHAKARAN; Regulation of Immune Responses by Vitamin B6; First published: May 1990 https://doi.org/10.1111/j.1749-6632.1990.tb28073.x
  9. Wintergerst ES, Maggini S, Hornig DH, 2007. Contribution of selected vitamins and trace elements to immune function. Ann. Nutr. Metab. 51, 301-323.
  10. Ellis JM, et al, Response of Vitamin B6 deficiency and the carpal tunnel syndrome to pyridoxine. ProcNatl Acad Sci USA 79, 7494- 7498, 1982
  11. Folkers K, Ellis J, Successful Therapy with Vitamin B6 and Vitamin B2 disease states. Annals NY Acad Sci 585, 295-301, 1990
  12. Ellis JM, Folkers K, Clinical aspects of the treatment of carpal tunnel syndrome with B6. Annals NY Acad Sci 585, 302- 320, 1990
  13. Bender DA, 2005. Vitamin B6. In: Caballero B, Allen L, Prentice A (eds). Encyclopedia of Human Nutrition. 2nd ed. Elsevier Academic Press, 359-367.
  14. Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children’s development and health, O.J.o.t.E. Union, Editor. 2012. p. 40
  15. Russ C, Hendricks T, Chrisley B, Khalin N, and Driskell J, Vitamin B status of depressed and obsessive-compulsive patients. Nutr Rep Intl 27, 867-873, 1983
  16. Carney M, Wiliams D, and Sheffield B, Thiamin and pyridoxine lack in newly admitted psychiatric patients. Br J Psychiatr 135, 249-254, 1979
  17. Nobbs B, Pyridoxal phosphate status in clinical depression. Lancet I, 405, 1974