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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"Laboratory investigation was performed in a sub-set of study participants (902 participants in years 2006–2008) to determine the concentrations of red blood cell (RBC) folate. Blood was drawn from the antecubital vein or from the hand of the participating women, and tested using the methods described by Branum et al . Samples were assayed in batches. "
[Show abstract][Hide abstract]ABSTRACT: This prospective cohort study designed to assess the effect of folic acid supplementation in pregnancy on the risk of preeclampsia (PE) took place in Ottawa, ON and Kingston, ON, Canada, from September 1, 2002 to August 31, 2008. Pregnant women, less than 20 weeks gestational age were recruited and delivered in the Ottawa region and the Kingston General Hospital. Demographic characteristics of the study participants and the patterns of supplementation of folic acid were described and occurrence of PE between women with folic acid supplementation during pregnancy and women without were compared. Multiple logistic regression was used in the estimation of the independent effect of supplementation of folic acid. Additional analyses assessing the effect of low RBC and serum folate and dose-response relationship were performed. Analyses were performed in all study participants, and then in high risk and low risk sub-groups, respectively. A total of 7,669 participants were included in the final analysis. Ninety five percent of the study participants were taking folic acid supplementation in early second trimester. The rate of PE was lower in the supplementation group than in the no supplementation group, and the difference was statistically significant in high risk women. Similar patterns of associations were observed in analysis by RBC and serum folate levels and in dose-response analysis. Folic acid supplementation in pregnancy may reduce PE risk in pregnant women, especially in those women with increased risk of developing PE.
"Over 30 years ago Sato et al. (1982) reported that even marginal Zn deficiency could affect oocyte maturation by doubling the number of degenerating oocytes and increasing chromosomal abnormalities in metaphase II oocytes . Despite the authors suggesting that preconception was a crucial time for women to ensure a sufficient intake of Zn, it would appear that attention in subsequent decades has shifted to Fe, folate and in more recent years, iodine supplementation181182183184185186. In studies designed to ascertain the reproductive effects of feeding virgin female mice a Zn-deficient diet, Taneja and Kaur observed retardation of ovarian follicular growth with varying degrees of atresia, lack of preovulatory follicles, a reduced and shrunken corpus luteum, and a fragmented zona pellucida and vitelline membrane, indicating the cessation of oogenesis and ovulation [187, 188]. "
[Show abstract][Hide abstract]ABSTRACT: Traditionally, research in the field of trace element biology and human and animal health has largely depended on epidemiological methods to demonstrate involvement in biological processes. These studies were typically followed by trace element supplementation trials or attempts at identification of the biochemical pathways involved. With the discovery of biological molecules that contain the trace elements such as matrix metalloproteinases (MMPs) containing Zinc (Zn); cytochrome P450 enzymes containing iron (Fe); and selenoproteins containing selenium (Se), much of the current research focuses on these molecules and hence only indirectly on trace elements themselves. This review focuses largely on two synchrotron-based X-ray techniques; X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF) imaging that can be used to identify the in situ speciation and distribution of trace elements in tissues, using our recent studies of bovine ovaries where the distribution of Fe, Se, Zn and bromine (Br) were determined. It also discusses the value of other techniques, such as inductively coupled plasma mass spectrometry, used to garner information about the concentrations and elemental state of the trace elements. These applications to measure trace elemental distributions in bovine ovaries at high resolutions provides new insights into possible roles for trace elements in the ovary.
Preview · Article · Feb 2016 · Biology of Reproduction
"Women of reproductive age are recommended to consume 0.4 mg of folic acid per day from fortified foods or supplements, or both, 2–3 months prior to conception and during pregnancy . Studies from Canada and the USA report the majority of women now consume supplements containing folic acid prior to and during pregnancy [114, 115]. Considering the important role of folate in nucleotide biosynthesis and DNA methylation  and hence cancer development and progression, the potential effect of high maternal and early life folate and folic acid exposure on cancer risk in the offspring has recently garnered significant attention. "
[Show abstract][Hide abstract]ABSTRACT: Folate and its synthetic form, folic acid, play an important role in one-carbon transfer reactions involved in DNA synthesis and methylation, aberrations of which contribute to the development of colorectal cancer. Indeed, a portfolio of epidemiologic evidence suggests an inverse association between folate status and colorectal cancer risk. However, animal studies and clinical trials collectively suggest a dual modulatory effect of folic acid supplementation on colorectal cancer risk depending on the stage of cell transformation at the time of intervention. Folic acid supplementation may prevent neoplastic initiation in the colorectum but it may promote the progression of established precancerous lesions. Concerns have been raised over whether or not the significantly increased intake and blood levels of folate resulting from folic acid fortification and prevalent supplemental folic acid use would increase the incidence and mortality of cancer in North America. Recent epidemiologic studies, however, have reported a decreasing trend of colorectal cancer incidence post-fortification in the USA and have not demonstrated a colorectal cancer-promoting effect of folic acid supplementation. Nevertheless, the effect of the dramatically increased folate status in North America on cancer incidence and mortality requires continued careful monitoring, given serious pubic health ramifications. At present, based on the lack of compelling supportive evidence and on the potential tumor-promoting effect, folic acid supplementation should not be recommended as a chemopreventive measure against colorectal cancer or any other cancers. Whether or not folic acid supplementation can prevent the development of colorectal cancer remains a highly controversial and complex topic at present.