ABSTRACT
Vitamin B-6 (Pyridoxine) is the form commonly used for food fortification and pharmaceutical preparations. The discovery of vitamin B-6 and its three forms, pyridoxine, pyridoxal, and pyridoxamine, has been detailed in a review by Snell. Vitamin B-6 is present in foods primarily in the form of pyridoxine, pyridoxal 5'-phosphate, and pyridoxamine phosphate. The main catabolite of pyridoxine metabolism is 4-pyridoxic acid. When vitamin B-6 is omitted from the diet, the excretion of 4-pyridoxic acid falls rapidly, but increases promptly with the readministration of the vitamin. The use of low dose oral contraceptives does not appear to have any long-term effects on vitamin B-6 requirements or status. Vitamin B-6 has an important role in the modulation of the immune response and infection. Alcohol has a systemic effect on the maintenance of blood pyridoxal 5'-phosphate concentrations.
