Vitamin B6 (pyridoxine)


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Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Hereditary sideroblastic anemia
Hereditary sideroblastic anemia is an X-linked disorder that prevents normal red blood cell function. Pyridoxine supplements are effective for treating this condition under the supervision of a qualified healthcare provider. 		A
Preventing adverse effects in people taking cycloserine (Seromycin®)
Cycloserine is a prescription antibiotic that may cause anemia, peripheral neuritis, or seizures by acting as a pyridoxine antagonist or increasing excretion of pyridoxine. Requirements for pyridoxine may be increased in patients receiving cycloserine. Pyridoxine may be recommended by a healthcare provider to prevent these adverse effects. 		A
Pyridoxine deficiency/ neuritis
Pyridoxine supplements are effective for preventing and treating pyridoxine deficiency and neuritis due to inadequate dietary intake, certain disease states, or deficiency induced by drugs such as isoniazid (INH) or penicillamine. Dietary supplements should be taken under the guidance of a qualified healthcare provider. 		A
Pyridoxine-dependent seizures in newborns
Pyridoxine-dependent seizures in newborns can result from the use of high-dose pyridoxine in pregnant mothers or from autosomal recessive (genetic) pyridoxine dependency. Refractory seizures in newborns that are caused by pyridoxine dependence may be controlled quickly with intravenous administration of pyridoxine by a qualified healthcare provider. 		A
Premenstrual syndrome (PMS)
There is some evidence that taking pyridoxine orally may improve symptoms of PMS such as mastalgia (breast pain or tenderness) and PMS-related depression or anxiety in some patients. Further research is needed before a conclusion can be made. 		B
Akathisia (movement disorder)
Some prescription drugs called neuroleptics, which are used in certain psychiatric conditions, may cause movement disorders as an unwanted side effect. Vitamin B6 has been studied for the treatment of acute neuroleptic-induced akathisia (NIA) in schizophrenic and schizoaffective disorder patients. Preliminary results indicate that high doses of vitamin B6 may be useful additions to the available treatments for NIA, perhaps due to its combined effects on various neurotransmitter systems. Further research is needed to confirm these results. 		C
Alzheimer's disease prevention
Hyperhomocysteinemia (high homocysteine levels in the blood) is a risk factor for Alzheimer's disease. Taking pyridoxine supplements alone or in combination with folic acid has been shown to be effective for lowering homocysteine levels. However, it is not clear if lowering homocysteine levels results in a reduced risk of Alzheimer's disease. Until definitive data are available, the current recommendation is screening of 40 year-old men and 50 year-old women for hyperhomocysteinemia. Further research is needed before a conclusion can be made. 		C
Angioplasty
There are conflicting findings about the potential benefit or harm of taking folic acid plus vitamin B6 and vitamin B12 following angioplasty. Further research is needed before a strong recommendation can be made. 		C
Anxiety
Studies of anxiety outcomes with vitamin B6 supplementation are limited. Well-designed clinical trials would be helpful in this area. 		C
Asthma
Preliminary research suggests that children with severe asthma may have inadequate pyridoxine status. Theophylline, a prescription drug used to help manage asthma, seems to lower pyridoxine levels. Studies of pyridoxine supplementation in asthma patients taking theophylline have yielded inconclusive results. Further research is needed before a strong conclusion can be drawn. 		C
Attention deficit hyperactivity disorder (ADHD)
Some research suggests that pyridoxine supplementation alone or in combination with other vitamins and minerals might help treat ADHD. Other studies show a lack of benefit. Further research is needed before a conclusion can be drawn. 		C
Birth outcomes
Studies of birth outcomes with vitamin B6 supplementation during pregnancy have yielded mixed results. Further well-designed clinical trials might be helpful in this area. 		C
Cancer prevention
There are data supporting the claim that vitamin B6 lowers the risk of colon cancer. Supplementation with a combination of folic acid, vitamin B6, and vitamin B12 did not decrease the risk of breast cancer. There is evidence that male smokers with higher serum levels of pyridoxine may have a lower risk of lung cancer. Well-designed clinical trials of pyridoxine supplementation are needed to confirm these results, and supplementation is not standard therapy at this time. 		C
Cardiovascular disease / hyperhomocysteinemia
Hyperhomocysteinemia (high homocysteine levels in the blood) is a risk factor for cardiovascular disease, blood clotting abnormalities, atherosclerosis, myocardial infarction (heart attack), and ischemic stroke. Taking pyridoxine supplements alone or in combination with folic acid has been shown to be effective for lowering homocysteine levels. However, it is not clear if lowering homocysteine levels results in reduced cardiovascular morbidity and mortality. Until definitive data are available, the current recommendation is screening of 40 year-old men and 50 year-old women for hyperhomocysteinemia. Decreased pyridoxine concentrations are also associated with increased plasma levels of C-reactive protein (CRP). CRP is an indicator of inflammation that is associated with increased cardiovascular morbidity in epidemiologic studies. In a large, long-term study, a combination pill containing folic acid, vitamin B6, and vitamin B12 did not reduce the risk of cardiovascular disease in high-risk women. More high-quality studies are needed. 		C
Carpal tunnel syndrome
Patients with carpal tunnel syndrome may have decreased vitamin B6 levels in their blood. Studies of pyridoxine supplementation in carpal tunnel syndrome have yielded inconclusive results. Well-designed clinical trials are needed before a firm conclusion can be drawn. 		C
Cognitive function
Preliminary studies suggest an association between low blood folate and poor cognitive test performance. However, this was not shown with vitamin B6. Well-designed research is needed. 		C
Depression
Preliminary evidence suggests that because pyridoxine increases serotonin and GABA levels in the blood, it may benefit people in dysphoric mental states. Increased homocysteine levels in the blood may increase the risk for later depression. Well-designed clinical trials are needed to confirm potential benefits. 		C
Diabetes
Preliminary research suggests pyridoxine may improve glucose metabolism. Well-designed research is needed to confirm these results. 		C
Dysmenorrhea (painful menstruation)
Preliminary research suggests pyridoxine may improve dysmenorrhea. Well-designed research is needed to confirm these results. 		C
Hyperkinetic cerebral dysfunction syndrome
There is preliminary evidence that pyridoxine supplementation might benefit hyperkinetic children who have low levels of blood serotonin. Further research is needed to confirm these results. 		C
Hypertension (high blood pressure)
Preliminary research suggests pyridoxine may reduce blood pressure in patients with high blood pressure. Well-designed research is needed to confirm these results. 		C
Immune system function
Vitamin B6 is important for immune system function, such as for production of antibodies. One study found that the amount of vitamin B6 required to reverse immune system impairments in elderly people was more than the current recommended dietary allowance (RDA). Well-designed clinical trials on vitamin B6 supplementation for this indication are needed before a recommendation can be made. 		C
Kidney stones (nephrolithiasis)
Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which can contribute to a certain type of kidney stones. Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation. Benefit has not been proven in other types of kidney stones, such as those associated with high urinary calcium, phosphorus, and creatinine. Further data are needed before a firm conclusion can be drawn. 		C
Lactation suppression
Studies of pyridoxine used to suppress lactation have yielded mixed results. Well-designed clinical trials are needed before a firm conclusion can be drawn. 		C
McArdle's disease
Vitamin B6 levels are low in the blood of many McArdle's patients. Preliminary research suggests pyridoxine is unlikely to help with symptoms of McArdle's disease. Well-designed research is needed to confirm these results. 		C
Osteoporosis prevention
Studies of pyridoxine supplementation for osteoporosis prevention have yielded inconclusive results. Well-designed clinical trials are needed before a firm conclusion can be drawn. 		C
Pain (breast)
Studies of breast pain outcomes with vitamin B6 supplementation are limited. Well-designed clinical trials would be helpful in this area. 		C
Pregnancy-induced nausea and vomiting
Studies of the use of pyridoxine alone or in combination with other antinausea treatments in pregnant women have yielded conflicting results. Further research is needed before a strong recommendation can be made. 		C
Preventing vitamin B6 deficiency associated with taking birth control pills
The need for vitamin B6 supplementation in women taking birth control pills has not been proven, although some studies have shown decreased pyridoxine levels in these women. Supplementation of B6 should be approached cautiously, since the long-term effect of such therapy is uncertain. 		C
Seizures (febrile)
Preliminary research suggests pyridoxine is unlikely to help with symptoms of febrile seizures. Well-designed research is needed to confirm these results. 		C
Tardive dyskinesia (involuntary movements)
Pyridoxine has some antioxidant effects, which theoretically may benefit patients with tardive dyskinesia. Results from a small high-quality trial suggest a benefit of vitamin B6 on symptoms of tardive dyskinesia. Further research is needed before a recommendation can be made. 		C
Autism
Studies of B6 supplementation alone or in combination with magnesium have not been shown to definitively benefit autism. Further research is needed. Autism should be treated by a qualified healthcare provider. 		D
Stroke reoccurrence
Pyridoxine alone or in combination with B12 and folic acid orally does not seem to be useful for preventing stroke recurrence. Further research is needed to determine the effect of vitamin B6 alone. 		D

Key to grades
A Strong scientific evidence for this use
B Good scientific evidence for this use
C Unclear scientific evidence for this use
D Fair scientific evidence against this use (it may not work)
F Strong scientific evidence against this use (it likely does not work)

Grading rationale

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Acne, alcohol intoxication, allergies, antioxidant, appetite stimulation, arthritis, chorea (an involuntary movement disorder), conjunctivitis (pinkeye), cystitis, dementia, diabetic neuropathy, diuresis (increased urine production), dizziness, Down's syndrome, epilepsy, high cholesterol, infertility, kidney failure, leg cramps (night leg cramps), menopausal symptoms, migraine headaches, motion sickness, muscle cramps, neural tube defects, Parkinson's disease, poisoning (mushroom), psychosis, radiation sickness, sickle cell anemia, skin conditions, sleep enhancement (improving dream recall), Tourette's syndrome.

Dosing Related terms
NS_patient-b6 Portions of this document last updated: Sept. 1, 2012

THIS EVIDENCE-BASED MONOGRAPH WAS PREPARED BY
THE NATURAL STANDARD RESEARCH COLLABORATION
(www.naturalstandard.com)

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