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(1) Background: Fortifying maize and wheat flours with folic acid has effectively reduced neural tube defect-affected births. However, maize and wheat flours may not be widely consumed in all countries; further reduction in neural tube defect-affected births could benefit from the identification of alternative food vehicles. We aimed to use dietary intake or apparent consumption data to determine alternative food vehicles for large-scale fortification with folic acid in low-income and lower-middle-income countries (LILMICs) and identify current research related to examining the technological feasibility of fortifying alternative foods with folic acid. (2) Methods: We identified 81 LILMICs, defined by the World Bank's (WB) 2018 income classifications. To identify dietary intake or apparent consumption, we reviewed WB's Microdata Library and Global Health Data Exchange for national surveys from 1997-2018. We reviewed survey reports for dietary intake or apparent consumption data and analyzed survey datasets for population coverage of foods. We defined alternative food vehicles as those that may cover/be consumed by ≥30% of the population or households; cereal grains (maize and wheat flours and rice) were included as an alternative food vehicle if a country did not have existing mandatory fortification legislation. To identify current research on fortification with folic acid in foods other than cereal grains, we conducted a systematic review of published literature and unpublished theses, and screened for foods or food products. (3) Results: We extracted or analyzed data from 18 national surveys and countries. The alternative foods most represented in the surveys were oil ( n = 16), sugar ( n = 16), and salt ( n = 14). The coverage of oil ranged from 33.2 to 95.7%, sugar from 32.2 to 98.4%, and salt from 49.8 to 99.9%. We found 34 eligible studies describing research on alternative foods. The most studied alternative foods for fortification with folic acid were dairy products ( n = 10), salt ( n = 6), and various fruit juices ( n = 5). (4) Conclusions: Because of their high coverage, oil, sugar, and salt emerge as potential alternative foods for large-scale fortification with folic acid. However, except for salt, there are limited or no studies examining the technological feasibility of fortifying these foods with folic acid.

Food fortification is designed to improve the nutritional profile of diets. The purpose of this research was to estimate the potential nutrient contribution of fortified maize flour, oil, rice, salt, and wheat flour in 153 countries, using the national intake (or availability) of the food and the nutrient levels required for fortification. This was done under two scenarios-maximum, where 100% of the food is assumed to be industrially processed and fortified, and realistic, where the maximum value is adjusted based on the percent of the food that is industrially processed and fortified. Under the maximum scenario, the median Estimated Average Requirements (EARs) met ranged from 22-75% for 14 nutrients (vitamins A, B1, B2, B3, B6, B12, D, E, folic acid and calcium, fluoride, iron, selenium and zinc), and 338% for iodine. In the realistic scenario, the median EARs met were 181% for iodine and <35% for the other nutrients. In both scenarios, the median Tolerable Upper Intake Levels (ULs) met were <55% for all nutrients. Under the realistic scenario, no country exceeded 100% of the UL for any nutrient. Current fortification practices of the five foods of interest have the global potential to contribute up to 15 nutrients to the diets of people, with minimal risk of exceeding ULs.

Our objective in this comment is to highlight several limitations in an ecological research study that was published in Nutrients by Murphy and Westmark (2020) in January 2020. The study used data from the Food Fortification Initiative (FFI) website, and applying an ecological study design, made an error of "ecologic fallacy" in concluding that "national fortification with folic acid is not associated with a significant decrease in the prevalence of neural tube defects (NTDs) at the population level". We list study limitations that led to their erroneous conclusions, stemming from incorrect considerations regarding NTD prevalence, the average grain availability for a country, the fortification coverage in a country, the population reach of fortified foods within a country, and the absence of the consideration of fortification type (voluntary vs. mandatory), country-specific policies on elective terminations for NTD-affected pregnancies, stillbirth proportions among those with NTDs, and fortification implementation. FFI data are derived from many sources and intended for fortification advocacy, not for hypothesis testing. The flawed study by Murphy & Westmark (2020) in Nutrients promotes a confusing and incorrect message to stakeholders, misguides policy makers, and hinders progress in global NTD prevention through a cost-effective, safe, and effective intervention: the mandatory large-scale folic acid fortification of staple foods.