Abstract
In the 6th revision of the Japanese Recommended Dietary Allowance (RDA)-Dietary Reference Intakes (DRI)-the RDA of folate was stated to be 200μg/day for an adult, all of which can be obtained from food. However, as evidence-based knowledge on this subject is insufficient, there is an obvious need for new data, collected by us in Japan, to be considered. To study the dietary requirement of folate, a group of healthy adults comprising 10 men and 10 women were fed a semi-purified diet following the Japanese RDA. In the women, the serum level and urinary excretion of folic acid were increased for the 8 days of the experiment. On the other hand, in the men, a decrease in the urinary excretion of folic acid was observed during the experimental period, but no change was noted in the serum level of folic acid. There was a sex difference in the dietary requirement of folic acid. These findings suggest that the 200μ/day intake used in this study would be adequate for maintaining a constant serum level of folic acid in women, but that a deficiency of folic acid might occur in this situation in men.
