Update on the impact of voluntary folic acid fortification of corn masa flour on red blood cell folate concentrations-National Health and Nutrition Examination Survey, 2011-March 2020.

BACKGROUND: Folic acid is a micronutrient that is effective at preventing neural tube defects (NTDs). In 2016, the FDA authorized the voluntary fortification of corn masa flour (CMF) with folic acid to reduce disparities in NTDs among infants of women who do not regularly consume other fortified cereal grains, in particular Hispanic women of reproductive age (WRA). METHODS: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to March 2020 assessing the impact of voluntary fortification of CMF on the folate status of Hispanic WRA. We analyzed folic acid usual intake and red blood cell (RBC) folate concentrations among non-pregnant, non-lactating Hispanic WRA, comparing pre-fortification (2011-2016) to post-fortification (2017-March 2020) data. RBC folate concentrations were used to create model-based estimation of NTD rates. RESULTS: The proportion of Hispanic WRA with folic acid usual intakes <400 µg/d did not change (2011-2016: 86.1% [95% Confidence Interval, CI: 83.7-88.5]; 2017-March 2020: 87.8% [95% CI: 84.8-90.7]; p = .38) nor did the proportion of Hispanic WRA with RBC folate below optimal concentrations (<748 nmol/L, 2011-2016: 16.0% [95% CI: 13.7-18.2]; 2017-March 2020: 18.1% [95% CI: 12.1-24.0]; p = 0.49). Model-based estimates of NTD rates suggest further improvements in the folate status of Hispanic WRA might prevent an additional 157 (95% Uncertainty Interval: 0, 288) NTDs/year. CONCLUSIONS: Voluntary fortification of CMF with folic acid has yet to have a significant impact on the folate status of WRA. Continued monitoring and further research into factors such as fortified product availability, community knowledge, and awareness of folic acid benefits would inform and improve future public health interventions.

Folate and vitamin B12 usual intake and biomarker status by intake source in United States adults aged ≥19 y: NHANES 2007-2018.

BACKGROUND: Folate and vitamin B12 are important biomarkers of nutritional status of populations. OBJECTIVES: This study aims to estimate folate and vitamin B12 usual intakes among United States adults and examine folate and vitamin B12 biomarker status by intake source. METHODS: We analyzed data for United States adults aged ≥19 y from National Health and Nutrition Examination Survey 2007-2018 (n = 31,128), during which time voluntary corn masa flour (CMF) fortification was started. Usual intake was estimated using the National Cancer Institute method. Folate intake included folate from natural foods and folic acid from 4 sources: enriched cereal grain products (ECGPs), CMF, ready-to-eat cereals (RTEs), and folic acid-containing supplements (SUP). Vitamin B12 intake was mainly from food and supplements. RESULTS: The median natural food folate intake (222 µg dietary folate equivalents (DFE)/d) was below the estimated average requirement (EAR) of 320 µg DFE/d. The proportions of those who consumed folic acid from ECGP/CMF only, ECGP/CMF + RTE, ECGP/CMF + SUP, and ECGP/CMF + RTE + SUP were 50%, 18%, 22%, and 10%, respectively. Median usual folic acid intakes (µg/d) were 236 (IQR: 152, 439) overall and 134, 313, 496, and 695 in the ECGP/CMF only, ECGP/CMF + RTE, ECGP/CMF + SUP, and ECGP/CMF + RTE + SUP folic acid consumption groups, respectively. Overall, 2.0% (95% CI: 1.7%, 2.3%) of adults, all of whom used folic acid supplements, consumed greater than the tolerable upper intake level (UL) of 1000 µg/d folic acid. The median usual vitamin B12 intake (µg/d) was 5.2 for vitamin B12 supplement nonusers and 21.8 for users. Consumption of RTE and/or supplements with folic acid was associated with higher serum and red blood cell folate concentrations. Vitamin B12 supplement users had significantly higher serum vitamin B12 concentrations. CONCLUSIONS: Folic acid fortification plays a critical role in helping United States adults meet the folate EAR. At current fortification levels, United States adults who do not consume supplements do not have the usual folic acid intake exceeding the UL.

Folic Acid and the Prevention of Birth Defects: 30 Years of Opportunity and Controversies.

For three decades, the US Public Health Service has recommended that all persons capable of becoming pregnant consume 400 µg/day of folic acid (FA) to prevent neural tube defects (NTDs). The neural tube forms by 28 days after conception. Fortification can be an effective NTD prevention strategy in populations with limited access to folic acid foods and/or supplements. This review describes the status of mandatory FA fortification among countries that fortify (n = 71) and the research describing the impact of those programs on NTD rates (up to 78% reduction), blood folate concentrations [red blood cell folate concentrations increased ∼1.47-fold (95% CI, 1.27, 1.70) following fortification], and other health outcomes. Across settings, high-quality studies such as those with randomized exposures (e.g., randomized controlled trials, Mendelian randomization studies) are needed to elucidate interactions of FA with vitamin B12 as well as expanded biomarker testing.