• Pyridoxine, Pyridoxine Hydrochloride, Pyridoxal-5-Phosphate
Vitamin B 6 plays a major role in making proteins, hormones, and neurotransmitters (chemicals that carry signals between nerve cells). Because mild deficiency of vitamin B 6 is common, this is one vitamin that is probably worth taking as insurance.
However, there is little evidence that taking vitamin B 6 above nutritional needs offers benefits in the treatment of any particular illnesses, except, possibly, nausea of pregnancy (morning sickness).
Vitamin B 6 requirements increase with age. The official US and Canadian recommendations for daily intake are as follows:
- 0-6 months: 0.1 mg
- 7-12 months: 0.3 mg
- 1-3 years: 0.5 mg
- 4-8 years: 0.6 mg
- 9-13 years: 1.0 mg
- 14-50 years: 1.3 mg
- 51 years and older: 1.7 mg
- 14-18 years: 1.2 mg
- 19-50 years: 1.3 mg
- 51 years and older: 1.5 mg
- Pregnant Women : 1.9 mg
- Nursing Women : 2.0 mg
Severe deficiencies of vitamin B 6 are rare, but mild deficiencies are extremely common. In a survey of 11,658 adults, 71% of men and 90% of women were found to have diets deficient in B 6 . 1
deficiency might be worsened by use of
One study found that 30 mg of vitamin B 6 daily was effective for symptoms of morning sickness. 17
The results of a large double-blind, placebo-controlled
has been proposed for numerous other uses as well, but without much (if any) scientific substantiation. For example, the two most famous uses of vitamin B
Higher intake of vitamin B
reduces the level of
A series of studies suggests that vitamin B
may be helpful for the treatment of TD. In the first study, a 4-week, double-blind crossover trial of 15 people, treatment with vitamin B
significantly improved TD symptoms as compared to placebo.
For the following other conditions, current evidence for benefit with vitamin B
remains incomplete and/or contradictory: allergy to monosodium glutamate (MSG),
Despite some claims in the media, vitamin B
has not shown benefit for
What Is the Scientific Evidence for Vitamin B 6 ?
Morning Sickness (Nausea and Vomiting in Pregnancy)
supplements have been used for years by conventional physicians as a treatment for
. In 1995, a large double-blind study validated this use.
At least 3 studies have compared vitamin B
Premenstrual Syndrome (PMS)
A recent, properly designed double-blind study of 120 women found no benefit of vitamin B
Approximately a dozen other double-blind studies have investigated the effectiveness of vitamin B
for PMS, but none were well designed; overall the evidence for any benefit is weak at best.
However, preliminary evidence suggests that the combination of B
and magnesium might be more effective than either treatment alone.
One double-blind, placebo-controlled
It has been suggested that combining magnesium with vitamin B
could offer additional benefits, such as reducing side effects or allowing a reduced dose of the vitamin. However, the two reasonably well-designed studies using combined vitamin B
and magnesium have failed to find benefits.
A double-blind study of 76 children with
The safe upper levels for daily intake of vitamin B 652
- 1-3 years: 30 mg
- 4-8 years: 40 mg
- Males and Females
- 9-13 years: 60 mg
- 14-18 years: 80 mg
- 19 years and older: 100 mg
- Pregnant or Nursing Women
- 18 years old and younger: 80 mg
- 19 years and older: 100 mg
At higher dosages (especially above 2 g daily) there is a very real risk of nerve damage. Nerve-related symptoms have even been reported at doses as low as 200 mg.
In addition, doses of vitamin B
over 5 mg may interfere with the effects of the drug
Maximum safe dosages for individuals with severe liver or kidney disease have not been established.
Interactions You Should Know About
If you are taking:
4. Hansen CM, Shultz TD, Kwak HK, et al. Assessment of vitamin B-6 status in young women consuming a controlled diet containing four levels of vitamin B-6 provides an estimated average requirement and recommended dietary allowance. J Nutr . 2001;131:1777-1786.
7. Delport R, Ubbink JB, Serfontein WJ, et al. Vitamin B6 nutritional status in asthma: the effect of theophylline therapy on plasma pyridoxal-5'-phosphate and pyridoxal levels. Int J Vitam Nutr Res . 1988;58:67-72.
23. Bell IR, Edman JS, Morrow FD, et al. Brief communication. Vitamin B 1 , B 2 , and B 6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr . 1992;11:159-163.
37. Folsom AR, Nieto FJ, McGovern PG, et al. Prospective study of coronary heart disease incidence in relation to fasting total homocysteine, related genetic polymorphisms, and B vitamins: the Atherosclerosis Risk in Communities (ARIC) study. Circulation . 1998;98:204-210.
42. De Souza MC, Walker AF, Robinson PA, et al. A synergistic effect of a daily supplement for 1 month of 200 mg magnesium plus 50 mg vitamin B6 for the relief of anxiety-related premenstrual symptoms: a randomized, double-blind, crossover study. J Womens Health Gend Based Med. 2000;9:131-139.
55. Gerritsen AA, de Krom MC, Struijs MA, Scholten RJ, de Vet HC, Bouter LM. Conservative treatment options for carpal tunnel syndrome: a systematic review of randomised controlled trials. J Neurol. 2002;249:272-280.
59. Findling RL, Maxwell K, Scotese-Wojtila L, et al. High-dose pyridoxine and magnesium administration in children with autistic disorder: an absence of salutary effects in a double-blind, placebo-controlled study. J Autism Dev Disord. 1997;27:467-478.
66. Lerner V, Bergman J, Statsenko N, et al. Vitamin b(6) treatment in acute neuroleptic-induced akathisia: a randomized, double-blind, placebo-controlled study. J Clin Psychiatry . 2004;65:1550-1554.
70. Chiang EP, Selhub J, Bagley PJ et al. Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis. Arthritis Res Ther . 2005;7:R1404-11.
Last reviewed April 2009 by EBSCO CAM Medical Review Board
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