Figure 10.25 Intestinal absorption of vitamin B6.

The bioavailability of dietary B6 glucoside (about 50%) is low compared to other B6 vitamers (Gregory, 1998). Incomplete hydrolysis of the glucoside and inhibition of interconversion reactions may be responsible; ε-pyridoxyllysine is a B6 form with low bioavailability that may be generated by heating or prolonged storage under reducing conditions. The normal Schiff base linkage with specific sites of B6-containing proteins readily dissolves in the inactive enzyme, especially upon hydrolysis of the protein. The covalent bond in ε-pyridoxyllysine, on the other hand, is less likely to dissociate ...

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