Folic acid intake among U.S. women of childbearing age with suboptimal red blood cell folate concentrations for neural tube defect prevention

Abstract

BackgroundA recent study reported that 22.8% of U.S. women of childbearing age have folate insufficiency, defined as red blood cell (RBC) folate below optimal concentrations needed for neural tube defect (NTD) prevention per guidelines established by the World Health Organization. Clinical trials have shown that consuming 400 μg of folic acid daily prevents NTDs.ObjectiveWe assessed the daily usual total folic acid intake and RBC folate status of women of childbearing age. We estimated the proportion of women consuming ≥400 μg folic acid/day, the daily amount recommended for NTD prevention for all women capable of becoming pregnant.MethodsWe used 2007–2012 data on non‐pregnant women aged 12–49 years (n = 4783) from the National Health and Nutrition Examination Survey (NHANES) and estimated daily usual total folic acid intake from all fortified foods and dietary supplements. Folate insufficiency was defined as an RBC folate concentration of <748 nmol/L using the NHANES microbiologic assay, which is associated with prevalence of NTDs of ≥9 cases per 10,000 live births.ResultsAmong all women in our study, 21.2% (95% confidence interval [CI]: 18.0, 24.3) had an average total folic acid intake of ≥400 μg /day from fortified foods and supplements. The prevalence of folate insufficiency was 22.5% (95% CI: 20.3, 24.9). Among the subgroup of women with folate insufficiency (n = 1196), only 3.9% (95% CI: 2.0, 5.7) achieved the recommended daily intake of folic acid. Among all women in our study, median usual daily total folic acid intake was highest among non‐Hispanic Whites (264 μg) and lowest among non‐Hispanic Blacks (185 μg). However, among women with folate insufficiency, the median usual daily total folic acid intake did not differ by race/ethnicity. Among women with folate insufficiency, 69.7% (95%CI: 64.8, 74.1) had mandatorily fortified foods (i.e., enriched cereal grain products) as their only source of folic acid; 12.6% (95% CI: 9.7, 16.1) reported taking supplements containing folic acid in the previous 30 days. Among folate‐insufficient women who did not use supplements, less than 1% had usual total folic acid intake ≥400 μg/day.ConclusionsThe majority of U.S. women of childbearing age with RBC folate below the optimal concentration do not consume the amount of folic acid recommended for NTD prevention. Targeted programs and guidance might increase folic acid intake among groups of women at higher risks for folate insufficiency.Support or Funding InformationThis work was supported by the CDC.