Vitamin B-6 (pyridoxine) is important for normal brain development and for keeping the nervous system and immune system healthy.
Food sources of vitamin B-6 include poultry, fish, potatoes, chickpeas and bananas. Vitamin B-6 can also be taken as a supplement, typically as an oral capsule, tablet or liquid.
People who have kidney disease or conditions that prevent the small intestine from absorbing nutrients from foods (malabsorption syndromes) are more likely to be vitamin B-6 deficient. Certain genetic diseases and some epilepsy medications also can lead to deficiency. This can cause a condition in which you don't have enough healthy red blood cells to carry adequate oxygen to your body's tissues (anemia), confusion, depression and a weakened immune system.
A vitamin B-6 deficiency is usually coupled with deficiency in other B vitamins, such as folate (vitamin B-9) and vitamin B-12.
The recommended daily amount of vitamin B-6 for adults is 1.3 milligrams.
Research on the use of vitamin B-6 for specific conditions shows:
- Heart and blood vessel disease and stroke. Vitamin B-6 has been shown to work together with folate (vitamin B-9) and vitamin B-12 to control high levels of homocysteine in the blood. Elevated homocysteine levels might increase your risk of diseases of the heart and blood vessels (cardiovascular disease). However, research hasn't shown that taking this mix of supplements reduces the risk or severity of cardiovascular disease and stroke.
- Morning sickness. Vitamin B-6 might reduce the severity of morning sickness during pregnancy. If you have persistent morning sickness symptoms, your pregnancy care provider might prescribe vitamin B-6 supplements.
- Premenstrual syndrome (PMS). There is some evidence that vitamin B-6 might reduce symptoms of PMS, however these studies are considered to be low quality.
- Sideroblastic anemia. Vitamin B-6 is effective at treating this genetic type of anemia.
A healthy and varied diet will provide most people with enough vitamin B-6. However, for people with kidney diseases, malabsorption syndromes and certain other conditions, a vitamin B-6 supplement is often necessary.
Vitamin B-6 supplements are also effective for treating a genetic form of anemia and for preventing an adverse reaction to the antibiotic cycloserine, a prescription drug taken to treat tuberculosis.
Safety and side effects
When used as a supplement in appropriate doses, vitamin B-6 is likely safe. High intake of vitamin B-6 through food hasn't been shown to be harmful.
However, too much vitamin B-6 also can cause:
- A lack of muscle control or coordination of voluntary movements (ataxia)
- Painful, disfiguring skin lesions
- Gastrointestinal symptoms, such as heartburn and nausea
- Sensitivity to sunlight (photosensitivity)
- Reduced ability to sense pain or extreme temperatures
Check with your doctor before taking vitamin B-6 if you are taking medications. Possible drug interactions include:
- Altretamine (Hexalen). Taking vitamin B-6 with this chemotherapy drug might reduce its effectiveness, especially when also combined with the chemotherapy drug cisplatin.
- Barbiturates. Taking vitamin B-6 with a drug that acts as a central nervous system depressant (barbiturate) might decrease the drug's duration and intensity.
- Anticonvulsants. Taking vitamin B-6 with fosphenytoin (Cerebyx) or phenytoin (Dilantin, Phenytek) might decrease the drug's duration and intensity.
- Levodopa. Avoid taking vitamin B-6 with this drug used to treat Parkinson's disease. Vitamin B-6 might reduce the effectiveness of the drug.