Vitamin B6

Vitamin B6, also called pyridoxine, is a water soluble vitamin that your body does not produce and must obtain from diet. Vitamin B6 is vital for many physiologic processes such as red blood cell synthesis, proper nerve function, energy synthesis, and DNA production.

Because vitamin B6 is a water-soluble nutrient, the body does not store it for future use. That means that your body will only get sufficient amounts when you ingest B6 on a daily basis.

Musculoskeletal Benefits of Vitamin B6

Vitamin B6 is required for the conversion of homocysteine to cysteine. High levels of homocysteine have been associated with:

  • Oxidative stress
  • Chronic inflammation
  • Increased fracture risk
  • Decreased bone mineral density
  • Collagen dysfunction.

Oxidative stress, chronic inflammation, and collagen dysfunction are associated with chronic musculoskeletal diseases such as osteoporosis, sarcopenia(muscle loss and weakness), osteoarthritis, and tendonitis. 

Vitamin B6 helps convert harmful levels of homocysteine to healthful levels of cysteine, a vital amino acid in human health. Cysteine is a key building block for glutathione. Glutathione plays outsized role in the body's natural antioxidant defenses.

Additionally, vitamin B6 is involved in synthesis of amino acids and conversion of fat and glucose into energy. Muscle and bone are metabolically hyper active; constantly building and breaking down. Any disruption in the building and energy generating processes causes a shift to an overall state of breakdown or “catabolism”. Many musculoskeletal diseases such as osteoporosis, osteoarthritis, and sarcopenia can be conceptualized as a situation in which the cellular machinery that destroys overwhelms the cellular machinery that builds. Insufficient vitamin B6 can magnify and accelerate this catabolic process.

Selected Evidence

1. Vitamin B6 Boosts Bone Health

Nigerian researchers examined the relationship of homocysteine and B6 with osteoporosis.The investigators found that high homocysteine serum and low vitamin B6 levels were found in individuals with osteoporosis. (Ebesunun et al. Plasma homocysteine, B vitamins and bone mineral density in osteoporosis: a possible risk for bone fracture.Arch Gynecol Obstet. 2009 Sep;280(3):381-7.)

2. Vitamin B6 Supports Muscle Health

Researchers in the Netherlands examined the nutritional status of older adults with sarcopenia.The investigators found that the serum concentration of vitamin B6 was significantly lower in the sarcopenic group compared to controls. (Ter Borg S et al. Differences in Nutrient Intake and Biochemical Nutrient Status Between Sarcopenic and Nonsarcopenic Older Adults-Results From the Maastricht Sarcopenia Study. J Am Med Dir Assoc. 2016 May 1;17(5):393-401.)

3. Vitamin B6 Promotes Joint Health

German researchers examined the effect of vitamin B6 on cartilage health in a rat model of osteoarthritis.The investigators found that a diet higher in B6 helped protect against osteoarthritis. The authors suggested vitamin B6 improves collagen strength via its interaction with lysyl oxidase, a key enzyme involved in collagen cross linking. (Kurz et al. Dietary vitamins and selenium diminish the development of mechanically induced osteoarthritis and increase the expression of antioxidative enzymes in the knee joint of STR/1N mice Osteoarthritis and Cartilage (2002) 10, 119-126)

Homocysteine Metabolism

Other Health Benefits 

There are other conditions that vitamin B6 may assist, although more research is needed and for some conditions results to date have been mixed. Those include:

  • Boosts healthy brain function
  • Promotes healthy hormone production
  • Supports heart health
  • May reduce the risk of certain types of cancer

Best Natural Sources for Vitamin B6

Rich sources are fish, fowl, leafy and root vegetables.

 

Recommended Dietary Allowance (RDA)

The Food and Nutrition Board has developed a table of recommended dietary allowances (RDAs) of vitamin B6, based on age and gender. The values are:

  • Infants up to six months, regardless of gender: 0.1 mg
  • Babies up to one year, regardless of gender: 0.3 mg
  • Children up to three years, regardless of gender: 0.5 mg
  • Children up to eight years, regardless of gender: 0.6 mg
  • Children up to 13 years, regardless of gender: 1.0 mg
  • Males from 14 to 50 years: 1.3 mg
  • Female teens up to 18 years: 1.2 mg
  • Female adults up to 50 years: 1.3 mg
  • Pregnant or lactating people from 14 to 50 years: 1.9 to 2 mg
  • Male adults over 50 years: 1.7 mg
  • Female adults over 50 years: 1.5 mg

Precautions

Vitamin B6 from natural foods is generally well tolerated. RDA amounts can usually be obtained from a balanced, healthful diet. 

The FNB has published an upper limit value of 100 mg /day. 

Excessive intake of supplemental vitamin B6 may be associated with neurologic symptoms, such as uncontrolled movements. Any consideration a supplementation should be discussed with a qualified health professional familiar with your unique medical history.

References

McCormick DB. Vitamin B6. In: Bowman BA, Russell RM, eds. Present Knowledge in Nutrition. Vol. I. Washington, D.C.: International Life Sciences Institute; 2006:269-277

Da Silva VR, Russell KA, Gregory JF 3rd. Vitamin B6. In: Erdman JW Jr., Macdonald IA, Zeisel SH. Present Knowldege in Nutrition. 10th ed: Wiley-Blackwell; 2012:307-320.

Ubbink JB, Vermaak WJ, van der Merwe A, Becker PJ, Delport R, Potgieter HC. Vitamin requirements for the treatment of hyperhomocysteinemia in humans. J Nutr. 1994;124(10):1927-1933. 

Carrington MJ, Bird TA, Levene CI. The inhibition of lysyl oxidase in vivo by isoniazid and its reversal by pyridoxal. Effect on collagen cross-linking in the chick embryo. Biochem J 1984;221:837-43.

Masse PG, Ziv I, Cole DE, Mahuren JD, Donavan SM, Yamauchi M, et al. A cartilage matrix deficiency experimentally induced by vitamin B6 deficiency. Proc Soc Exp Biol Med 1998;217:97-103.

Kuo HK, Liao KC, Leveille SG, et al. Relationship of homocysteine levels to quadriceps strength, gait speed, and late-life disability in older adults. J Gerontol A Biol Sci Med Sci 2007;62:434e439

Clarke, M.; Ward, M.; Strain, J.J.; Hoey, L.; Dickey, W.; McNulty, H. B-vitamins and bone in health and disease: The current evidence. Proc. Nutr. Soc. 2014, 73, 330–339.

Van Meurs, J.B.J.; Dhonukshe-Rutten, R.A.M.; Pluijm, S.M.F.; van der Klift, M.; de Jonge, R.; Lindemans, J. Homocysteine levels and the risk of osteoporotic fracture. N. Engl. J. Med. 2004, 350, 2033–2041.

http://www.umm.edu/Health/Medical/AltMed/Supplement/Vitamin-B6-Pyridoxine

http://www.nap.edu/catalog.php?record_id=6015

https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/#h7

http://www.dietitians.ca/Nutrition-Resources-A-Z/Factsheets/Vitamins/Food-Sources-of-Vitamin-B6-(Pyridoxine).aspx

https://www.medicalnewstoday.com/articles/219662.php

http://www.encyclopedia.com/science-and-technology/biochemistry/biochemistry/pyridoxine