Dietary folate intakes and effects of folic acid supplementation on folate concentrations among Japanese pregnant women

Aim: To quantify the consumed amount of dietary folate and to evaluate effects of folic acid and balanced diets on serum folate concentrations. Material & Methods: Food records collected from 641 pregnant women were assessed to quantify the consumed amount of dietary folate for a 6-year period from 2003 to 2008. Changes in serum folate concentrations were evaluated among 80 pregnant women who either took folic acid tablets or consumed balanced diets in 2008. Results: Though the dietary folate intake averaged 331 mu g daily, 200 women in the 1st trimester consumed the least amount of dietary folate, 294 mu g daily. It was observed that 42% of the 200 women either consumed at least 440 mu g of dietary folate daily or took 400 mu g folic acid supplements daily, but that 58% of them neither consumed dietary folate of 440 mu g nor took folic acid supplements. Intakes of 400 mu g folic acid supplements for 5 weeks resulted in a significant increase in serum folate concentrations but the consumption of balanced diets had no effect on increasing folate concentrations. Conclusions: The average intake of dietary folate did not fulfill the Recommended Dietary Allowance of 440 mu g. Serum folate concentration significantly increased only among pregnant women who took folic acid supplements. Recommendations to consume balanced diets do not seem effective to decrease the incidence of neural tube defects.