Women Taking a Folic Acid Supplement in Countries with Mandatory Food Fortification Programs May Be Exceeding the Upper Tolerable Limit of Folic Acid: A Systematic Review.
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ABSTRACT: Background
In preconception and pregnancy, women are encouraged to take folic acid-based supplements over and above food intake. The upper tolerable limit of folic acid is 1000 mcg per day; however, this level was determined to avoid masking a vitamin B12 deficiency and not based on folic acid bioavailability and metabolism. This review's aim is to assess the total all-source intake of folate in women of childbearing age and in pregnancy in high-income countries with folate food fortification programs.Methods
A systematic search was conducted in five databases to find studies published since 1998 that reported folate and folic acid intake in countries with a mandatory fortification policy.Results
Women of childbearing age do not receive sufficient folate intake from food sources alone even when consuming fortified food products; however, almost all women taking a folic acid-based supplement exceed the upper tolerable limit of folic acid intake.Conclusions
Folic acid supplement recommendations and the upper tolerable limit of 1000 mcg set by policy makers warrant careful review in light of potential adverse effects of exceeding the upper tolerable limit on folic acid absorption and metabolism, and subsequent impacts on women's health during their childbearing years.
SUBMITTER: Ledowsky C
PROVIDER: S-EPMC9268323 | biostudies-literature |
REPOSITORIES: biostudies-literature
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2016-11-12 | GSE89781 | GEO
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| S-EPMC7820780 | biostudies-literature
Project description:BACKGROUND:Enriched cereal-grain products have been fortified in the United States for >20 y to improve folate status in women of reproductive age and reduce the risk of folic acid-responsive neural tube birth defects (NTDs). OBJECTIVES:Our objectives were to assess postfortification changes in folate status in the overall US population and in women aged 12-49 y and to characterize recent folate status by demographic group and use of folic acid-containing supplements. METHODS:We examined cross-sectional serum and RBC folate data from the NHANES 1999-2016. RESULTS:Serum folate geometric means increased from 2007-2010 to 2011-2016 in persons aged ?1 y (38.7 compared with 40.6 nmol/L) and in women (35.3 compared with 37.0 nmol/L), whereas RBC folate showed no significant change. Younger age groups, men, and Hispanic persons showed increased serum and RBC folate concentrations, whereas non-Hispanic black persons and supplement nonusers showed increased serum folate concentrations. The folate insufficiency prevalence (RBC folate <748 nmol/L; NTD risk) in women decreased from 2007-2010 (23.2%) to 2011-2016 (18.6%) overall and in some subgroups (e.g., women aged 20-39 y, Hispanic and non-Hispanic black women, and supplement nonusers). After covariate adjustment, RBC folate was significantly lower in all age groups (by ?10-20%) compared with persons aged ?60 y and in Hispanic (by 8.2%), non-Hispanic Asian (by 12.1%), and non-Hispanic black (by 20.5%) compared with non-Hispanic white women (2011-2016). The 90th percentile for serum (?70 nmol/L) and RBC (?1800 nmol/L) folate in supplement nonusers aged ?60 y was similar to the geometric mean in users (2011-2014). CONCLUSIONS:Blood folate concentrations in the US population overall and in women have not decreased recently, and folate insufficiency rates are ?20%. Continued monitoring of all age groups is advisable given the high folate status particularly in older supplement users.
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