Vitamin B₆ (pyridoxine) is essential for the metabolism of carbohydrates, amino acids, and fats (lipids), as well as for normal nerve function and for the formation of red blood cells. It also helps keep the skin healthy.

Vitamin B₆ Deficiency

• Many foods contain vitamin B₆, but extensive processing can remove the vitamin.
• People may have seizures, a scaly rash, a red tongue, cracks in the corners of the mouth, or a pins-and-needles sensation in the hands and feet.
• The diagnosis is based on symptoms, the presence of possible causes, and response to vitamin B₆ supplements.
• Vitamin B₆ supplements, taken by mouth, can correct the deficiency.

Because vitamin B₆ is present in many foods, the deficiency rarely results from inadequate intake. However, such a deficiency can occur because extensive processing can remove vitamin B₆ from foods. The deficiency often results from malabsorption disorders, alcoholism, or use of drugs that deplete vitamin B₆ stored in the body. These drugs include the antibiotic isoniazid, the antihypertensive hydralazine, and penicillamine (used to treat such disorders as rheumatoid arthritis and Wilson's disease).

Vitamin B₆ deficiency can cause seizures, particularly in infants. Anticonvulsants may be ineffective in treating these seizures. In adults, the deficiency can cause inflammation of the skin (dermatitis) and a red, greasy, scaly rash. The hands and feet may feel numb and prickling—like pins and needles. The tongue may become sore and red, and cracks may form in the corners of the mouth. People may become confused, irritable, and depressed. Because vitamin B₆ is needed to form red blood cells, deficiency can cause anemia.

The diagnosis is based on the symptoms, the presence of conditions that can cause the deficiency, and response to vitamin B₆ supplements. Blood tests to confirm the diagnosis are not readily available.

Causes are corrected when possible. People who have the deficiency or who are taking a drug that depletes vitamin B₆ in the body should take vitamin B₆ supplements by mouth.

Vitamin B₆ Excess

Vitamin B₆ in very high doses may be prescribed for such disorders as carpal tunnel syndrome, premenstrual syndrome, and nerve damage (neuropathy), although there is little evidence of benefit. Taking such high doses may cause pain and numbness in the feet and legs. People may be unable to tell where their arms and legs are (position sense) and to feel vibrations. Thus, walking becomes difficult.

The diagnosis is based on symptoms and a history of taking high doses of vitamin B₆. Treatment involves stopping vitamin B₆ supplements. Recovery from this disorder may be slow, and people may continue to have some difficulty walking.

Did You Know... High doses of vitamin B6 supplements probably do not help people with carpal tunnel syndrome, premenstrual syndrome, and nerve damage and can have harmful effects.

Last full review/revision August 2007 by Larry E. Johnson, MD, PhD