Bentley, T. G. K., Willett, W. C., Weinstein, M. C., & Kuntz, K. M. (2006). American Journal of Public Health, 96, 2040-2047.

In 1998, in an effort to reduce the number of neural tube defects (NTDs), the FDA mandated that all enriched grain products be fortified with folic acid. This policy was expected to add about 100 mg/day of folic acid to the diet of the average person in the United States. The expected outcome was that the percent of childbearing women (aged 15-44 years) receiving at least 400 mg/day of the vitamin would increase from 29% to 50%. By examining food and folic acid supplement intake and correcting for measurement error (what a woman eats in a single day versus folic acid consumed on an average day over time), this national study is the first attempt to see if that increase occurred. Although the study analyzed data for men and women in three age groups and of three races/ethnicities, I will comment only on the results for childbearing (aged 15-44) White, Black, and Mexican American women.

Results demonstrated that all childbearing women increased their average folate intake by at least 100 mg/day after fortification. The rate of women of childbearing age who consumed more than 400 mg/day of total folate increased anywhere from 26% to 38% but did not reach the 50% target for any of the racial/ethnic groups. Black and Mexican American women lagged behind White women in reaching the 400 mg/day folate consumption threshold, with rates lowest among Blacks (20% prefortification and 26% postfortification) and highest among Whites (30% prefortification and 39% postfortification), with Mexican Americans in the middle (17% prefortification and 28% postfortification). Because food intake seems similar among all three groups before and after fortification, results suggest that differences in supplement use account for differences in the three groups. White women may have higher total folate consumption because they are more likely to take supplements, including prenatal vitamins. The good news is that there were large increases in the number of childbearing women of all races/ethnicities who consumed more than 200 mg of folate daily. The bad news was that there were disparities in folate consumption among White, Black, and Mexican American women and that the disparities were related to supplement use. Why are Black and Mexican American women less likely to ingest folate supplements, including prenatal vitamins? Does it indicate that these groups are not receiving comparable prenatal care or that they are less likely to take prenatal vitamins because of side effects or cultural factors? Tailored interventions to provide folate supplements and promote their use must be made among minority women of childbearing age to further reduce the risk of NTDs in our country.

Linda Beth Tiedje