Vitamin B6

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Vitamin B6 is a water soluble vitamin belonging to the group of B complex vitamins. It was first isolated in the 1930’s and has been extensively studied. Vitamin B6 has a variety of chemical forms including pyridoxine, pyridoxal and pyridoxamine. It was originally referred to as “antidermatitis factor” because of its observed role in treatment of skin inflammation. It performs a wide variety of functions in the body and is essential for good health.

Contents

Functions

Vitamin B6 is needed for more than hundred enzymes which are involved in chemical reactions in the body. Some of the important functions of this vitamin are as follows:

  • Nervous system: Involved in the synthesis of neurotransmitters including serotonin, which is synthesized from the amino acid tryptophan.
  • Red blood cell formation: Important for the synthesis of heme, an iron-containing component of hemoglobin in the blood.
  • Niacin formation: Essential for conversion of amino acid tryptophan into niacin, thus, adequate vitamin B6 decreases the requirement for dietary niacin.
  • Essential for proper cell division and multiplication
  • Critical for a healthy immune system
  • Essential for protein and fat metabolism
  • May alleviate symptoms of pre-menstrual syndrome

Food Sources

Vitamin B6 is found in a wide variety of foods. Excellent sources of vitamin B6 include bell peppers, turnip greens, and spinach. Other good food sources include beans, meat, poultry, fish, some fruits and vegetables such as cauliflower, broccoli, cabbage, asparagus and banana. Cereals are also fortified with vitamin B6. Large amounts of vitamin B6 are lost during most forms of cooking. Processing procedures like canning and freezing also lead to destruction of vitamin B6.

Recommended Dosage

Specific recommendations for vitamin B6 depend on age, gender, and other factors (such as pregnancy). In 2000, the National Academy of Sciences established Recommended Dietary Allowances for vitamin B6 for all individuals. These recommendations are as follows:

  • Males 14-50 years: 1.3 milligrams
  • Males 51 years and older: 1.7 milligrams
  • Females 14-50: 1.2 milligrams
  • Females 51 years and older: 1.5 milligrams
  • Pregnant females of any age: 1.9 milligrams
  • Lactating females of any age: 2.0 milligrams

Refer to What can foods high in vitamin B6 do for you?


In general, a healthy diet typically supplies enough vitamin B6.

Deficiency

Severe deficiency of vitamin B6 is uncommon. Alcoholics, smokers and women who use hormonal contraceptives could require additional vitamin B6. Some of the symptoms of vitamin B6 deficiency are:

  • inflammation of the tongue
  • sores or ulcers of the mouth
  • dermatitis (skin inflammation)
  • nerve related symptoms like depression, confusion and convulsions
  • irritability
  • anaemia
  • sleeplessness

Toxicity

Although vitamin B6 is a water-soluble vitamin and is excreted in the urine, long-term supplementation with very high doses of pyridoxine may result in painful neurological symptoms known as sensory neuropathy. Symptoms include pain and numbness of the extremities and can lead to difficulty in walking. Sensory neuropathy typically develops at doses of pyridoxine in excess of 1,000 mg per day. To prevent sensory neuropathy, the Food and Nutrition Board of the Institute of Medicine has set the tolerable upper intake level (UL) for pyridoxine at 100 mg/day for adults.

References

  • Dietary Supplement Fact Sheet: Vitamin B6
  • Vitamin B6
  • Vitamin B6 - pyridoxine - information page
  • Natural Health Information Centre
  • What can foods high in vitamin B6 do for you?

See Also