Konjac Mannan Improves the Vitamin B-6 Status of Rats Fed a Vitamin B-6-deficient Diet

To investigate how dietary fiber in the diet affects vitamin B-6 nutriture of rats which have been deprived of vitamin B-6, rats were made vitamin B-6-deficient by feeding a vitamin B-6-deficient 70% casein diet. They were fed 2% cellulose powder-based vitamin B-6-deficient diets supplemented with 3% of additional dietary fiber sources (agar, konjac mannan, pectin and cellulose powder) for subsequent 18 days. Vitamin B-6 status was evaluated according to several biological criteria (weight gain, urinary excretion of xanthurenic acid after tryptophan loading, plasma pyridoxal 5’-phosphate, apparent pyridoxal 5’-phosphate-saturation of liver kynureninase, urinary excretion of 4-pyridoxic acid and fecal output of vitamin B-6). Vitamin B-6 status evaluated by these criteria was considerably improved in the konjac mannan-fed group, when compared with the respective data of the vitamin B-6 supplemented group. The relative mean effect of the konjac mannan diet was about 40% of the vitamin B-6 supplemented diet. In conclusion, konjac mannan was effective for improving the vitamin B-6 nutritional state in vitamin B-6-deprived rats.