Vitamin B6

Vitamin B₆

Vitamin B₆ is composed of three related forms: pyridoxine, pyridoxal, and pyri-doxamine. It is stable to heat but sensitive to light and alkalies.

Functions.Vitamin B₆is essential for protein metabolism and absorption,and it aids in the release of glucose from glycogen. With the help of vitamin B₆, amino acids present in excessive amounts can be converted to those in which the body is temporarily deficient. It also serves as a catalyst in the conversion of tryptophan to niacin, and it is helpful in the formation of other substances from amino acids. An example is the synthesis of neurotransmitters such as serotonin and dopamine.

Sources.Some of the nutrient-dense sources of vitamin B₆are poultry,fish, liver, kidney, potatoes, bananas, and spinach. Whole grains, especiallyoats and wheat, are good sources of vitamin B₆, but because this vitamin is lost during milling and is not replaced during the enrichment process, refined grains are not a good source.

Requirements.Vitamin B₆is measured in milligrams, and the need in-creases as the protein intake increases. For adult females, the daily requirement is 1.3 to 1.5 mg and for males, 1.3 to 1.7 mg. Oral contraceptives interfere with the metabolism of vitamin B₆ and can result in a deficiency.

Deficiency.A deficiency of vitamin B₆is usually found in combination withdeficiencies of other B vitamins. Symptoms include irritability, depression, and dermatitis. In infants, its deficiency can cause various neurological symptoms and abdominal problems. Although its toxicity is rare, it can cause temporary neurological problems.