Bioavailability of vitamin B-6 from plant foods.

The major factors that affect bioavailability of vitamin B-6 are formation of reaction products during food processing, fiber type and content, and presence of the conjugated pyridoxine glucoside. The bioavailability of vitamin B-6 from animal products is quite high, reaching 100% for many foods. In general the bioavailability from plant foods is lower. The presence of fiber reduces the bioavailability by 5-10% whereas the presence of pyridoxine glucoside reduces the bioavailability by 75-80%. This glucoside is found in a variety of plant foods, with the highest content occurring in the crucifers. The percent of total vitamin B-6 that exists as the glucoside has been suggested to be the best indicator of bioavailability. Data from Nepalese vegetarian lactating women suggest that the low vitamin B-6 status of these mothers and their infants, as determined by their concentrations of plasma pyridoxal phosphate, may be adversely affected by the dietary intake of the naturally occurring pyridoxine glucoside.