Achieving a public health recommendation for preventing neural tube defects with folic acid.

OBJECTIVES: This study examined 3 approaches to achieving the public health recommendation that all women of child-bearing age ingest 0.40 mg of folic acid per day to reduce the occurrence of neural tube defects (NTDs).
METHODS: A total of 1136 mothers of infants with major malformations from the Boston and Philadelphia areas, whose pregnancies began from 1993 to 1995, were interviewed within 6 months of delivery about vitamin supplementation, dietary intakes, and other factors.
RESULTS: Seventy-one percent of the 1136 women in the study did not take folic acid--containing supplements daily before conception, but the proportion decreased over the years of the study. Women not taking supplements consumed an average of 0.25 mg of naturally occurring folates daily. On the basis of dietary intakes reported by women not taking folic acid supplements, a simulation of cereal grain fortification with folic acid at the level required by the US Food and Drug Administration showed that an average of only 0.13 mg of folic acid would be ingested daily.
CONCLUSIONS: With consumption of folic acid only through dietary intake, sizeable portions of the childbearing population would receive less than the level of folic acid recommended for preventing NTDs. Even with food fortification, women of childbearing age should be advised to take folic acid--containing supplements on a daily basis.