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Vitamin B6 Deficiency


Larry E. Johnson

, MD, PhD, University of Arkansas for Medical Sciences

Last full review/revision Nov 2020| Content last modified Nov 2020
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Vitamin B6 is in most foods, but people can have vitamin B6 deficiency if they do not absorb it properly.

  • 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.

Vitamin B6 (pyridoxine) is essential for the processing (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. (See also Overview of Vitamins.)

Good sources of vitamin B6 include dried yeast, liver, other organ meats, whole-grain cereals, fish, and legumes.

Causes of Vitamin B6 Deficiency

Because vitamin B6 is present in many foods, the deficiency rarely results from inadequate intake except in severe malnutrition. However, deficiency can also occur, because extensive processing can remove vitamin B6 from foods.

Vitamin B6 deficiency often results from

These drugs include antiseizure drugs, the antibiotic isoniazid (used for tuberculosis), hydralazine (used to treat high blood pressure), corticosteroids, and penicillamine (used to treat such disorders as rheumatoid arthritis and Wilson disease).

Vitamin B6 deficiency is common among people who have had a severe deficiency of protein and calories (protein-energy undernutrition). People with this disorder do not consume enough vitamin B6.

Symptoms of Vitamin B6 Deficiency

In adults, vitamin B6 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. They may have seizures.

Rarely, vitamin B6 deficiency causes seizures in infants. Antiseizure drugs may be ineffective in treating these seizures in infants.

Because vitamin B6 is needed to form red blood cells, deficiency can cause anemia.

Diagnosis of Vitamin B6 Deficiency

  • History and physical examination

  • Response to vitamin B6 supplements

The diagnosis of vitamin B6 deficiency is based on symptoms, the presence of conditions that can cause the deficiency, and response to vitamin B6 supplements.

Blood tests may be done, but no routine blood test can clearly confirm the diagnosis.

Treatment of Vitamin B6 Deficiency

  • Correction of the cause

  • Vitamin B6 supplements

Causes of vitamin B6 deficiency are corrected when possible.

If people have the deficiency or if they are taking a drug that depletes vitamin B6 in the body, they should take vitamin B6 supplements by mouth. Taking vitamin B6 supplements usually corrects the deficiency in adults.

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