Dietary Supplement Use and Folate Status during Pregnancy in the United States

National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, MD.
Journal of Nutrition (Impact Factor: 3.88). 01/2013; 143(4). DOI: 10.3945/jn.112.169987
Source: PubMed


Adequate folate and iron intake during pregnancy is critical for maternal and fetal health. No previous studies to our knowledge have reported dietary supplement use and folate status among pregnant women sampled in NHANES, a nationally representative, cross-sectional survey. We analyzed data on 1296 pregnant women who participated in NHANES from 1999 to 2006 to characterize overall supplement use, iron and folic acid use, and RBC folate status. The majority of pregnant women (77%) reported use of a supplement in the previous 30 d, most frequently a multivitamin/-mineral containing folic acid (mean 817 μg/d) and iron (48 mg/d). Approximately 55-60% of women in their first trimester reported taking a folic acid- or iron-containing supplement compared with 76-78% in their second trimester and 89% in their third trimester. RBC folate was lowest in the first trimester and differed by supplement use across all trimesters. Median RBC folate was 1628 nmol/L among users and 1041 nmol/L among nonusers. Among all pregnant women, median RBC folate increased with trimester (1256 nmol/L in the first, 1527 nmol/L in the second, and 1773 nmol/L in the third). Given the role of folic acid in the prevention of neural tube defects, it is notable that supplement use and median RBC folate was lowest in the first trimester of pregnancy, with 55% of women taking a supplement containing folic acid. Future research is needed to determine the reasons for low compliance with supplement recommendations, particularly folic acid, in early pregnancy.

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    • "Periconceptional folic acid supplementation level Based on our investigation, folic acid supplementation in pregnant WWE was of shorter duration than that in the general population. Almost 91.3% of pregnant women are reportedly taking folic acid supplementation during their current pregnancy in Canada [23]; this rate is approximately 73.9% in the USA [24] and almost 86% in the Netherlands [25]. A recent survey conducted in China revealed that more than 80% of women take folic acid supplementation while pregnant [26]. "
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    ABSTRACT: The aims of this study were to investigate the implementation of guidelines on periconceptional folic acid supplementation among pregnant women with epilepsy (WWE) in China and to identify its potential correlations with selected sociodemographic and clinical factors. A detailed investigation was conducted in China using a structured questionnaire from December 2013 to May 2014. Data on the awareness and use of folic acid supplementation, as well as sociodemographic and clinical characteristics, were collected from 153 pregnant WWE. Descriptive analysis, followed by univariate and multivariate logistic regression analyses, was applied to the data from this survey. Among the enrolled subjects, 67.3% became pregnant after the promulgation of the relevant guidelines. Only 26.2% of them knew the exact effects of folic acid, and 73.8% had taken folic acid at some point during periconception. In addition, the folic acid intake of most of these women (67.1%) did not exceed that of the average pregnant woman. The prevalence of folic acid supplementation for pregnant WWE three months before pregnancy was only 15.5%. There has been almost no improvement in the level of additional awareness and use of folic acid supplementation for WWE since the relevant guidelines were established in China. Pregnant WWE with higher education levels, those with a planned pregnancy, or those who live in urban areas were more likely to know about and implement folic acid supplementation during periconception. Moreover, pregnant WWE with a planned pregnancy or those living in cities seemed to have a higher folic acid intake and started folic acid supplementation earlier before conception. The extent of awareness and use of folic acid supplementation in pregnant WWE remains low in China. More efforts are needed to promote periconceptional folic acid supplementation for WWE, especially those with low education levels and those who live in rural areas. Planned pregnancy should be encouraged for WWE. Copyright © 2014. Published by Elsevier Inc.
    Full-text · Article · Jan 2015 · Epilepsy & Behavior
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    • "The red blood cell folate concentrations presented by Pfeiffer et al 2012 and Branum et al 2013 were generated by a microbiological assay (calibrated with 5' methylTHF) that was normalized to the microbiological assay used in the Folic Acid Dosing Trial and the Daly study (calibrated with folic acid) using the equation: NHANES red blood cell folate (nmol/L)=(Daly and Folic Acid Dosing Trial red blood cell folate (nmol/L)×0.7876)+34.2802 (nmol/L) (personal communication from the data presented in Pfeiffer et al 2011). "
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    ABSTRACT: Objective To determine an optimal population red blood cell (RBC) folate concentration for the prevention of neural tube birth defects. Design Bayesian model. Setting Data from two population based studies in China. Participants 247 831 participants in a prospective community intervention project in China (1993-95) to prevent neural tube defects with 400 μg/day folic acid supplementation and 1194 participants in a population based randomized trial (2003-05) to evaluate the effect of folic acid supplementation on blood folate concentration among Chinese women of reproductive age. Intervention Folic acid supplementation (400 μg/day). Main outcome measures Estimated RBC folate concentration at time of neural tube closure (day 28 of gestation) and risk of neural tube defects. Results Risk of neural tube defects was high at the lowest estimated RBC folate concentrations (for example, 25.4 (95% uncertainty interval 20.8 to 31.2) neural tube defects per 10 000 births at 500 nmol/L) and decreased as estimated RBC folate concentration increased. Risk of neural tube defects was substantially attenuated at estimated RBC folate concentrations above about 1000 nmol/L (for example, 6 neural tube defects per 10 000 births at 1180 (1050 to 1340) nmol/L). The modeled dose-response relation was consistent with the existing literature. In addition, neural tube defect risk estimates developed using the proposed model and population level RBC information were consistent with the prevalence of neural tube defects in the US population before and after food fortification with folic acid. Conclusions A threshold for “optimal” population RBC folate concentration for the prevention of neural tube defects could be defined (for example, approximately 1000 nmol/L). Population based RBC folate concentrations, as a biomarker for risk of neural tube defects, can be used to facilitate evaluation of prevention programs as well as to identify subpopulations at elevated risk for a neural tube defect affected pregnancy due to folate insufficiency.
    Full-text · Article · Jul 2014 · BMJ Clinical Research
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    ABSTRACT: BACKGROUND: Folate, choline, and betaine participate in homocysteine metabolism. It is not known whether they interact during pregnancy. OBJECTIVE: The objective was to investigate how folate status affects choline, betaine, and dimethylglycine during pregnancy. DESIGN: Fasting plasma folate, cobalamin, free choline, betaine, dimethylglycine, and total homocysteine (tHcy) were measured longitudinally at <12, 15, 24-27, and 34 gestational weeks (GW); at labor (nonfasting); and in the cord in participants (n = 522) from the Reus-Tarragona Birth Cohort (NUTrició i Creixement Intrauterí Retardat phase). Timing, dose, and duration of folic acid supplement use were recorded. Folate status was classified as below (low) or above (high) median plasma folate at baseline (27.6 nmol/L) and at 24-27 GW (11.4 nmol/L). Associations between folate or betaine with tHcy were investigated by using multiple linear regression analysis. RESULTS: Plasma betaine decreased by 34.8% (1.0%) throughout pregnancy, and dimethylglycine increased by 39.7% (2.7%) between 24-27 GW and labor (all P < 0.001). Low folate status was associated with a higher dimethylglycine/betaine ratio from 15 GW and with lower plasma betaine and higher dimethylglycine from 24 to 27 GW, for the rest of pregnancy, compared with high status. Regression analysis showed that by 24-27 GW, both plasma folate and betaine were inversely associated with tHcy when folate status was low and that the association between betaine and tHcy depended on folate status at 24-27 and 34 GW (interaction terms: P < 0.001 and P < 0.01). Betaine was inversely associated with tHcy at labor regardless of folate status. CONCLUSION: Low folate status enhances the reduction in betaine and the increase in dimethylglycine during pregnancy and strengthens the association between betaine and tHcy. This trial was registered at as NCT01778205.
    Full-text · Article · Apr 2013 · American Journal of Clinical Nutrition
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