Fortification of Foods with Folic Acid — How Much is Enough?

In the early 1990s two randomized clinical trials showed that folic acid, or multivitamins containing folic acid, could substantially reduce a woman's risk of bearing a child with a neural-tube defect, provided that the vitamins were taken before conception.1,2 In 1992 the Public Health Service recommended that all women of childbearing age who are capable of becoming pregnant consume 400 μg of folic acid daily.3 Not surprisingly, in a country where half the women who become pregnant each year are not planning to do so, compliance with this recommendation has been poor.4 At the time the recommendation was made, we . . .