Bioavailibility of vitamin B-6 from wheat bread in humans

In order to test the feasibility of enriching a cereal product with vitamin B6, the bioavailability of the vitamin was assessed in the diets of 9 healthy men consuming whole wheat bread, white bread with an oral dose of pyridoxine, and white bread enriched with B6. Samples of diets, urine, feces and blood were analyzed for vitamin B6 content. Pyridoxine and pyridoxal were the main forms of vitamin B6 found in the diet and urine, respectively. Whole wheat bread produced an increase in fecal B6 excretion, and a decrease in urinary 4-pyridoxic acid excretion, and a slightly lower plasma pyridoxal phosphate level. Type of bread did not affect urinary B6 excretion, plasma B6 or erythrocyte transaminase activity. It seems that vitamin B6 is 5-10% less bioavailable in whole wheat bread, making the enrichment of refined flour a feasible step