Vitamin B-6

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, bananas and fortified cereals. 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 autoimmune disorders, some epilepsy medications and alcohol dependence also can lead to vitamin B-6 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 folic acid (vitamin B-9) and vitamin B-12.

The recommended daily amount of vitamin B-6 for adults 50 and younger is 1.3 milligrams. After age 50, the recommended daily amount is 1.5 milligrams for women and 1.7 milligrams for men.

Research on the use of vitamin B-6 for specific conditions shows:

• Heart and blood vessel disease and stroke. Researchers had previously believed that vitamin B-6, when combined with folic acid (vitamin B-9) and vitamin B-12, might prevent diseases of the heart and blood vessels by reducing the levels of an amino acid in the blood (homocysteine). However, studies show that the combination of these vitamins doesn't seem to reduce 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 nausea and vomiting, 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 may be 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 (Seromycin), a prescription drug taken to treat tuberculosis.

Consuming vitamin B-6 through food appears to be safe, even in excessive amounts.

When used as a supplement in appropriate doses, vitamin B-6 is likely safe.

However, taking too much vitamin B-6 from supplements can cause:

• A lack of muscle control or coordination of voluntary movements (ataxia)
• Painful, disfiguring skin lesions
• Heartburn and nausea
• Sensitivity to sunlight (photosensitivity)
• Numbness
• Reduced ability to sense pain or extreme temperatures

Check with your doctor before taking vitamin B-6 if you're using any medications. Possible drug interactions include:

• Altretamine. 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, Sesquient) 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.