10.72 Vitamin B6 Deficiency & Toxicity

Vitamin B6 deficiency is rare, but symptoms include:

Skin or scalp ailments (seborrheic dermatitis)

Microcytic hypochromic anemia (small cells, low color)




Given what we know about the functions of vitamin B6 most of these symptoms make sense.

The microcytic hypochromic anemia is a result of decreased heme synthesis. The neurological symptoms are due to the decreased production of neurotransmitters1.

Vitamin B6, unlike many of the B vitamins, can produce toxicity. High doses of vitamin B6, taken for an extended period of time, can lead to neurological damage2. There are some potential uses of vitamin B6 supplementation that are important to be done with consultation with a physician.

One of the conditions that people take vitamin B6 for is carpal tunnel syndrome. The following video does a nice job of explaining and showing how this condition occurs.

Web Link

Video: Carpal Tunnel Syndrome (1:02)

While the evidence is not conclusive, it appears that vitamin B6 supplementation may be beneficial to those suffering from carpal tunnel syndrome and may be tried alone, or in combination with other complementary treatments, before surgery is undertaken3,4.

Morning sickness that occurs early in pregnancy is another condition where vitamin B6 supplementation is utilized. The evidence again is not clear on whether it is beneficial5,6, but The American College of Obstetricians and Gynecologists suggests that vitamin B6 may be tried first to treat nausea and vomiting during pregnancy7. In 2013, the FDA approved doxylamine-pyridoxine (Diclegis) for use in pregnancy8. It is not known exactly what causes morning sickness, but it is believed that lower circulating vitamin B6 levels are associated with increased morning sickness severity9.

The last condition that vitamin B6 is commonly supplemented for is premenstrual syndrome (PMS). A systematic literature review found that it is inconclusive whether vitamin B6 supplementation is beneficial in managing PMS10.

References & Links

1. Stipanuk MH. (2006) Biochemical, physiological, & molecular aspects of human nutrition. St. Louis, MO: Saunders Elsevier.

2. Stipanuk MH. (2006) Biochemical, physiological, & molecular aspects of human nutrition. St. Louis, MO: Saunders Elsevier.

3. Ryan-Harshman M, Aldoori W. (2007) Carpal tunnel syndrome and vitamin B6. Canadian Family Physician 53(7): 1161-1162.

4. Aufiero E, Stitik T, Foye P, Chen B. (2004) Pyridoxine hydrochloride treatment of carpal tunnel syndrome: A review. Nutr Rev 62(3): 96-104.

5. Koren G, Maltepe C. (2006) Preventing recurrence of severe morning sickness. Canadian Family Physician 52(12): 1545-1546.

6. Tan P, Yow C, Omar S. (2009) A placebo-controlled trial of oral pyridoxine in hyperemesis gravidarum. Gynecol Obstet Invest 67(3): 151-157.

7. http://www.acog.org/Patients/FAQs/Morning-Sickness-Nausea-and-Vomiting-of-Pregnancy

8. Slaughter SR, Hearns-Stokes R, van der Vlugt T, Joffe HV. (2014) FDA approval of doxylamine-pyridoxine therapy for use in pregnancy. N Engl J Med. 370: 1081-1083.

9. Wibowo N, Purwosunu Y, Sekizawa A, Farina A, Tambunan V, Bardosono S. (2012) Vitamin B6 supplementation in pregnant women with nausea and vomiting. 116: 206-210.

10. Whelan A, Jurgens T, Naylor H. (2009) Herbs, vitamins and minerals in the treatment of premenstrual syndrome: A systematic review. The Canadian Journal of Clinical Pharmacology 16(3): e407-e429.


Carpal Tunnel Syndrome – http://www.youtube.com/watch?v=rewDQgqU5Hg