Homocysteine concentration, related B vitamins, and betaine in pregnant women recruited to the Seychelles Child Development Study

Biomarkers of seafood intake during pregnancy - Pollutants versus fatty acids and micronutrients

Intake of fish and seafood during pregnancy may have certain beneficial effects on fetal development, but measurement of intake using questionnaires is unreliable. Here, we assessed several candidate biomarkers of seafood intake, including long-chain omega 3 fatty acids (n-3 LCPUFA), selenium, iodine, methylmercury, and different arsenic compounds, in 549 pregnant women (gestational week 29) in the prospective birth cohort NICE (Nutritional impact on Immunological maturation during Childhood in relation to the Environment). Proportions of the fatty acids eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) in erythrocytes were measured using gas chromatography with flame ionization detector. Selenium was measured in blood plasma and erythrocytes, mercury and arsenic in erythrocytes, and iodine and several arsenic compounds in urine, using inductively coupled plasma mass spectrometry, arsenic compounds after first being separated by ion exchange high-performance liquid chromatography (HPLC). Each biomarker was related to intake of total seafood and to intake of fatty and lean fish, and shellfish in third trimester, estimated from a semi-quantitative food frequency questionnaire filled out in gestational week 34. The pregnant women reported a median total seafood intake of 184 g/week (5th-95th percentiles: 34-465 g/week). This intake correlated most strongly with erythrocyte mercury concentrations (rho = 0.49, p < 0.001), consisting essentially of methylmercury, followed by total arsenic in erythrocytes (rho = 0.34, p < 0.001), and arsenobetaine in urine (rho = 0.33, p < 0.001), the main form of urinary arsenic. These biomarkers correlated well with intake of both fatty fish, lean fish, and shellfish. Erythrocyte DHA and plasma selenium correlated, although weakly, mainly with fatty fish (rho = 0.25 and 0.22, respectively, both p < 0.001). In conclusion, elevated concentrations of erythrocyte mercury and urinary arsenobetaine can be useful indicators of seafood intake, more so than the n-3 LCPUFAs. However, the relative importance of the biomarkers may differ depending on the type and amount of seafood consumed.

Trimethylamine N-Oxide and Its Precursors Are Associated with Gestational Diabetes Mellitus and Pre-Eclampsia in the Boston Birth Cohort

Background

Trimethylamine N-oxide (TMAO) and its precursors choline, betaine, and carnitine have been associated with cardiometabolic disease in nonpregnant adults. However, studies examining TMAO and its precursors in relation to cardiometabolic conditions during pregnancy are lacking.

Objectives

The primary objective was to estimate the association of TMAO and its precursors in maternal and cord plasma with gestational diabetes mellitus (GDM) and pre-eclampsia (PE) among women in the Boston Birth Cohort. A secondary objective was to determine whether associations vary by race/ethnicity.

Methods

ORs for each outcome according to tertiles and to an SD increment of TMAO, choline, betaine, and carnitine were estimated using logistic regression. Final models were adjusted for covariates.

Results

Among 1496 women, 115 women had GDM and 159 had PE during the index pregnancy. Intermetabolite correlations of TMAO and its precursors were stronger within cord plasma (r = 0.38-0.87) than within maternal plasma (r = 0.08-0.62). Maternal TMAO was associated with higher odds of GDM (third compared with first tertile OR: 1.75; 95% CI: 1.04, 2.94), whereas maternal choline, betaine, and carnitine were not associated with GDM. Maternal TMAO and choline were not associated with PE, whereas carnitine was associated with higher (OR: 1.86; 95% CI: 1.18, 2.94) and betaine with lower odds of PE (OR: 0.37; 95% CI: 0.23, 0.59). In cord plasma, TMAO was not associated with GDM or PE, but choline, betaine, and carnitine were associated with higher odds of PE (OR: 3.11; 95% CI: 1.62, 5.96; OR: 2.65; 95% CI: 1.42, 4.93; OR: 2.56; 95% CI: 1.39, 4.69, respectively). Cord choline was associated with lower odds of GDM (OR: 0.52; 95% CI: 0.27, 0.99), whereas other cord metabolites were not significantly associated with GDM. Associations did not vary by race/ethnicity.

Conclusions

TMAO and its precursors were associated with GDM and PE, but the associations differed based on the metabolite medium (maternal compared with cord plasma).This trial was registered at clinicaltrials.gov as NCT03228875.

A Novel Review of Homocysteine and Pregnancy Complications

Homocysteine (Hct) is a substance produced in the metabolism of methionine. It is an essential type of amino acid gained from the daily diet. Methylenetetrahydrofolate reductase (MTHFR) gene mutation is related to elevated total homocysteine (tHct) expressions, in particular, among women with low folate intake. Hyperhomocysteinemia (HHct) is caused by numerous factors, such as genetic defects, lack of folic acid, vitamin B₆ and B₁₂ deficiency, hypothyroidism, drugs, aging, and renal dysfunction. Increased Hct in peripheral blood may lead to vascular illnesses, coronary artery dysfunction, atherosclerotic changes, and embolic diseases. Compared to nonpregnant women, the Hct level is lower in normal pregnancies. Recent studies have reported that HHct was associated with numerous pregnancy complications, including recurrent pregnancy loss (RPL), preeclampsia (PE), preterm delivery, placental abruption, fetal growth restriction (FGR), and gestational diabetes mellitus (GDM). Besides, it was discovered that neonatal birth weight and maternal Hct levels were negatively correlated. However, a number of these findings lack consistency. In this review, we summarized the metabolic process of Hct in the human body, the levels of Hct in different stages of normal pregnancy reported in previous studies, and the relationship between Hct and pregnancy complications. The work done is helpful for obstetricians to improve the likelihood of a positive outcome during pregnancy complications. Reducing the Hct level with a high dosage of folic acid supplements during the next pregnancy could be helpful for females who have suffered pregnancy complications due to HHct.

Glutathione Protects the Developing Heart from Defects and Global DNA Hypomethylation Induced by Prenatal Alcohol Exposure

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is caused by prenatal alcohol exposure (PAE), the intake of ethanol (C2 H5 OH) during pregnancy. Features of FASD cover a range of structural and functional defects including congenital heart defects (CHDs). Folic acid and choline, contributors of methyl groups to one-carbon metabolism (OCM), prevent CHDs in humans. Using our avian model of FASD, we have previously reported that betaine, another methyl donor downstream of choline, prevents CHDs. The CHD preventions are substantial but incomplete. Ethanol causes oxidative stress as well as depleting methyl groups for OCM to support DNA methylation and other epigenetic alterations. To identify more compounds that can safely and effectively prevent CHDs and other effects of PAE, we tested glutathione (GSH), a compound that regulates OCM and is known as a "master antioxidant."

METHODS/RESULTS

Quail embryos injected with a single dose of ethanol at gastrulation exhibited congenital defects including CHDs similar to those identified in FASD individuals. GSH injected simultaneously with ethanol not only prevented CHDs, but also improved survival and prevented other PAE-induced defects. Assays of hearts at 8 days (HH stage 34) of quail development, when the heart normally has developed 4-chambers, showed that this single dose of PAE reduced global DNA methylation. GSH supplementation concurrent with PAE normalized global DNA methylation levels. The same assays performed on quail hearts at 3 days (HH stage 19-20) of development, showed no difference in global DNA methylation between controls, ethanol-treated, GSH alone, and GSH plus ethanol-treated cohorts.

CONCLUSIONS

GSH supplementation shows promise to inhibit effects of PAE by improving survival, reducing the incidence of morphological defects including CHDs, and preventing global hypomethylation of DNA in heart tissues.

Serum Betaine and Dimethylglycine Are Higher in South Asian Compared with European Pregnant Women in Canada, with Betaine and Total Homocysteine Inversely Associated in Early and Midpregnancy, Independent of Ethnicity

BACKGROUND

As a methyl donor required in the folate-vitamin B-12 independent remethylation of total homocysteine (tHcy) to methionine, betaine is critical for fetal development. Pregnant South Asian women living in Canada had a higher reported prevalence of low vitamin B-12 status compared with Europeans; betaine concentrations in this population are unknown.

OBJECTIVES

We aimed to compare serum betaine concentrations between South Asian and European pregnant women, and to determine the relation between betaine and tHcy concentrations in early pregnancy.

METHODS

A retrospective cohort study was conducted using biobanked serum samples of 723 apparently healthy pregnant women of South Asian (50%) and European ethnicity residing in British Columbia, Canada. Betaine, dimethylglycine (DMG), tHcy, and related metabolites were quantified in samples collected in the first (8-13 weeks of gestation) and second (14-20 weeks of gestation) trimesters. The relation between betaine and tHcy concentrations was assessed using a generalized regression model adjusted for weeks of gestation, ethnicity, prepregnancy BMI, maternal age, neonatal sex, parity, total vitamin B-12, folate, pyridoxal 5'-phosphate, and methionine concentrations.

RESULTS

Median serum concentrations of betaine and its metabolite DMG were higher in South Asian women in the first (19.8 [IQR: 16.3-25.0] and 1.55 [IQR: 1.30-1.96] $\mu {\rm mol/L} $, respectively) and second trimesters (16.1 [IQR: 12.9-19.8] and 1.42 [IQR: 1.14-1.81] $\mu {\rm mol/L} $, respectively) compared with European women (17.6 [IQR: 13.7-22.6] and 1.38 [IQR: 1.12-1.77] $\mu {\rm mol/L} $, respectively) and (12.9 [IQR: 10.6-16.7] and 1.19 [IQR: 0.97-1.52] $\mu {\rm mol/L} $, respectively; all P values < 0.0001). Betaine was inversely associated with tHcy concentration (β = -0.0208; 95% CI: -0.0341, -0.00742; P = 0.002). Additionally, total vitamin B-12 was associated with tHcy concentration (β = -0.0312; 95% CI: -0.0401, -0.0224), after adjusting for confounding factors.

CONCLUSIONS

Pregnant South Asian women residing in Canada had higher betaine and DMG concentrations, compared with women of European ethnicity, while betaine and total vitamin B-12 predicted tHcy independent of ethnicity. Our results emphasize the role of betaine, as methyl donor, in the remethylation of tHcy in a folate-replete population.

Candidate genes linking maternal nutrient exposure to offspring health via DNA methylation: a review of existing evidence in humans with specific focus on one-carbon metabolism

Background

Mounting evidence suggests that nutritional exposures during pregnancy influence the fetal epigenome, and that these epigenetic changes can persist postnatally, with implications for disease risk across the life course.

Methods

We review human intergenerational studies using a three-part search strategy. Search 1 investigates associations between preconceptional or pregnancy nutritional exposures, focusing on one-carbon metabolism, and offspring DNA methylation. Search 2 considers associations between offspring DNA methylation at genes found in the first search and growth-related, cardiometabolic and cognitive outcomes. Search 3 isolates those studies explicitly linking maternal nutritional exposure to offspring phenotype via DNA methylation. Finally, we compile all candidate genes and regions of interest identified in the searches and describe their genomic locations, annotations and coverage on the Illumina Infinium Methylation beadchip arrays.

Results

We summarize findings from the 34 studies found in the first search, the 31 studies found in the second search and the eight studies found in the third search. We provide details of all regions of interest within 45 genes captured by this review.

Conclusions

Many studies have investigated imprinted genes as priority loci, but with the adoption of microarray-based platforms other candidate genes and gene classes are now emerging. Despite a wealth of information, the current literature is characterized by heterogeneous exposures and outcomes, and mostly comprise observational associations that are frequently underpowered. The synthesis of current knowledge provided by this review identifies research needs on the pathway to developing possible early life interventions to optimize lifelong health.

Effect of homocysteine on pregnancy: A systematic review

Research purpose was to put together the available pieces of present scientific data and to close the gap in the knowledge of Hcy levels in pregnancy and its association with some pregnancy complications. Scientific data were taken from research papers published between January 1990 and December 2017, and found on the Internet (PubMed, ClinicalKey and Embase databases) by the following tags entered in English, Russian, French and German languages: pregnancy, homocysteine, pregnancy complications, pregnancy loss, preeclampsia, intrauterine growth restriction, and placental abruption. The review showed that Hcy levels range in uncomplicated pregnancy. Upon that, Hcy level tends to decrease during the second and third trimesters. Some studies have revealed a link between polymorphism and abortion. Sufficient data were obtained indicating the relationship between HHcy and PE. Placental abruption was also associated with high Hcy levels increasing the risk 5.3-fold, but still there are data not supporting the hypothesis that Hcy levels correlate with placental abruption.

Early pregnancy folate-cobalamin interactions and their effects on cobalamin status and hematologic variables throughout pregnancy

Background

Periconception folic acid supplementation is widespread, but how it interacts with cobalamin status is rarely considered.

Objective

The aim of this study was to investigate whether first-trimester folate-cobalamin interactions affect pregnancy cobalamin status, hematologic variables, and pregnancy outcomes.

Design

In the longitudinal Reus-Tarragona Birth Cohort study from <12 gestational weeks throughout pregnancy, fasting plasma and red blood cell (RBC) folate, plasma cobalamin, holotranscobalamin (holoTC), methylmalonic acid (MMA), total homocysteine (tHcy), hemoglobin, mean cell volume (MCV), postglucose-load serum glucose, gestational hypertension, gestational age at birth, and birth weight were recorded in 563 participants.

Results

The highest plasma folate concentrations occurred in the first trimester when folic acid supplement use was extensive. Supplementation beyond the first trimester interacted with time of pregnancy on plasma folate, RBC folate, and tHcy throughout pregnancy (P-interaction <0.001). Plasma folate and RBC folate were higher and tHcy was lower in continued supplement users than in nonusers. Elevated plasma folate (≥30 nmol/L) occurred in 78.9% of women who exceeded the recommended 400 µg folic acid/d. First-trimester folate-cobalamin status interactions were associated with MMA (P-interaction <0.001) throughout pregnancy. When plasma cobalamin was suboptimal (≤221 pmol/L; n = 36), participants with elevated plasma folate (n = 11) had higher MMA concentrations than did those with nonelevated plasma folate (n = 23). First-trimester folate-MMA status interactions were associated with MCV throughout pregnancy (P-interaction <0.01) and with cord plasma holoTC (P-interaction <0.05). The mean difference (95% CI) in MCV (fL) between women with elevated and nonelevated plasma folate status was -2.12 (-3.71, -0.52) for top-quartile plasma MMA (≥0.139 µmol/L) and 0.60 (-0.39, 1.60) for plasma MMA <0.139 µmol/L. Cord plasma holoTC was higher in women with elevated compared with nonelevated plasma folate status only for MMA <0.139 µmol/L. Folate-cobalamin interactions were not associated with the other investigated outcomes.

Conclusion

First-trimester folate-cobalamin status interactions were associated with plasma MMA and MCV throughout pregnancy. This trial was registered at www.clinicaltrials.gov as NCT01778205.

Early pregnancy B vitamin status, one carbon metabolism, pregnancy outcome and child development

Periconception supplementation with folic acid is recommended until 12 gestational weeks to prevent neural tube defects. Doses of folic acid contained in supplements and timing and length of use during pregnancy vary. The effects of status in periconception and pregnancy folate, cobalamin, betaine and their interactions on one carbon metabolism (1C), as well as the global effect of 1C on foetal growth and pregnancy outcome, are reviewed. Results from prospective studies are reviewed. Cessation of folic acid supplement use after the first trimester is associated with a sharp drop in plasma folate status and enhanced conversion of betaine to dimethylglycine. Dimethylglycine production is also higher in mothers with low folate status than in those with normal-high folate status. The effects of high doses of folic acid on one carbon metabolism in mothers with low early pregnancy cobalamin status and on foetal growth are also reviewed. Several studies report that moderately elevated early pregnancy fasting plasma total homocysteine (tHcy) is inversely associated with birth weight and a predictor of intrauterine growth retardation. There is also evidence for increased risk of preterm birth when maternal folate status is low.

Low maternal vitamin B12 status is associated with lower cord blood HDL cholesterol in white Caucasians living in the UK

Background and Aims: Studies in South Asian population show that low maternal vitamin B12 associates with insulin resistance and small for gestational age in the offspring. Low vitamin B12 status is attributed to vegetarianism in these populations. It is not known whether low B12 status is associated with metabolic risk of the offspring in whites, where the childhood metabolic disorders are increasing rapidly. Here, we studied whether maternal B12 levels associate with metabolic risk of the offspring at birth. Methods: This is a cross-sectional study of 91 mother-infant pairs (n = 182), of white Caucasian origin living in the UK. Blood samples were collected from white pregnant women at delivery and their newborns (cord blood). Serum vitamin B12, folate, homocysteine as well as the relevant metabolic risk factors were measured. Results: The prevalence of low serum vitamin B12 (<191 ng/L) and folate (<4.6 μg/L) were 40% and 11%, respectively. Maternal B12 was inversely associated with offspring’s Homeostasis Model Assessment 2-Insulin Resistance (HOMA-IR), triglycerides, homocysteine and positively with HDL-cholesterol after adjusting for age and BMI. In regression analysis, after adjusting for likely confounders, maternal B12 is independently associated with neonatal HDL-cholesterol and homocysteine but not triglycerides or HOMA-IR. Conclusions: Our study shows that low B12 status is common in white women and is independently associated with adverse cord blood cholesterol.

Folate, vitamin B12 and Homocysteine status in the post-folic acid fortification era in different subgroups of the Brazilian population attended to at a public health care center

BACKGROUND

Folate and vitamin B12 are essential nutrients, whose deficiencies are considerable public health problems worldwide, affecting all age groups. Low levels of these vitamins have been associated with high concentrations of homocysteine (Hcy) and can lead to health complications. Several genetic polymorphisms affect the metabolism of these vitamins. The aims of this study were to assess folate, vitamin B12 and homocysteine status in distinct Brazilian individuals after the initiation of folic acid fortification by Brazilian authorities and to investigate the effects of RFC1 A80G, GCPII C1561T and MTHFR C677T polymorphisms on folate, vitamin B12 and Hcy levels in these populations.

METHODS

A total of 719 individuals including the elderly, children, as well as pregnant and lactating women were recruited from our health care center. Folate, vitamin B12 and Hcy levels were measured by conventional methods. Genotype analyses of RFC1 A80G, GCPII C1561T and MTHFR C677T polymorphisms were performed by PCR-RFLP.

RESULTS

The overall prevalence of folate and vitamin B12 deficiencies were 0.3% and 4.9%, respectively. Folate deficiency was observed only in the elderly (0.4%) and pregnant women (0.3%), whereas vitamin B12 deficiency was observed mainly in pregnant women (7.9%) and the elderly (4.2%). Plasma Hcy concentrations were significantly higher in the elderly (33.6%). Pregnant women carrying the MTHFR 677TT genotype showed lower serum folate levels (p = 0.042) and higher Hcy levels (p = 0.003). RFC1 A80G and GCPII C1561T polymorphisms did not affect folate and Hcy levels in the study group. After a multivariate analysis, Hcy levels were predicted by variables such as folate, vitamin B12, gender, age and RFC1 A80G polymorphism, according to the groups studied.

CONCLUSION

Our results suggest that folate deficiency is practically nonexistent in the post-folic acid fortification era in the subgroups evaluated. However, screening for vitamin B12 deficiency may be particularly relevant in our population, especially in the elderly.

Child's homocysteine concentration at 2 years is influenced by pregnancy vitamin B12 and folate status

Longitudinal studies investigating vitamin B12 and folate status of mothers and their offspring will provide a better understanding of intergenerational nutrition. During pregnancy and 2 years (2y) after delivery, we measured plasma vitamin B12 and folate concentrations in 118 women [aged (mean ± s.d.) 22.9 ± 3.9y] who attended a rural (n = 68) or an urban (n = 50) antenatal clinic in Pune, India. Cord blood vitamin B12 and folate were measured, and when the child was 2y total homocysteine (tHcy) was also measured. Demographic and diet measurements were recorded using standard methods. Pregnancy plasma vitamin B12 concentration at 34 weeks was low [median (25th, 75th), 115 (95, 147) pm]; 75% had low status (<150 pm). Plasma folate was high (mean ± s.d., 33 ± 21 nm); one had a folate concentration <7 pm. Cord plasma vitamin B12 and folate concentrations were higher than and positively associated with maternal concentrations. In stepwise regression, higher child vitamin B12 at 2y was predicted (total R 2 15.7%) by pregnancy vitamin B12 (std β 0.201, R 2 7.7%), current consumption of cow's milk (std β 0.194, R 2 3.3%) and whether breast feeding was stopped before 2y (std β -0.234 R 2 7.2%). Child's 2y tHcy concentration was high (11.4 ± 3.6 μm) and predicted by lower pregnancy vitamin B12 (std β -0.206, R 2 4.1%), lack of vitamin supplementation (std β -0.256, R 2 5.6%) in pregnancy and whether currently breastfed (std β 0.268, R 2 8.4%). Low maternal vitamin B12 status in pregnancy and prolonged breast-feeding results in disturbed one-carbon metabolism in offspring at 2y. Supplementation of women of child-bearing age, particularly during pregnancy and lactation, may improve the homocysteine status of these children.

Revisiting the role of first trimester homocysteine as an index of maternal and fetal outcome

Aim. To revisit the role of first trimester homocysteine levels with the maternal and fetal outcome. Methods. This was a cohort study comprising 100 antenatal women between 8 and 12 weeks of gestation. Serum homocysteine levels were checked after overnight fasting. Results. There were significantly elevated homocysteine levels among women with prior history of hypertensive disorders of pregnancy and prior second or third trimester pregnancy losses. There was no significant difference in homocysteine levels among women with previous gestational diabetes mellitus, preterm deliveries, or fetal malformations. Homocysteine levels were significantly elevated in those who developed hypertensive disorder of pregnancy, oligohydramnios, and meconium stained amniotic fluid, had a pregnancy loss, or delivered a low birth weight baby. There was no significant difference in homocysteine levels for those who developed gestational diabetes mellitus. Conclusions. Increased first trimester serum homocysteine is associated with history of pregnancy losses, hypertensive disorders of pregnancy, and preterm birth. This is also associated with hypertensive disorders of pregnancy, pregnancy loss, oligohydramnios, meconium stained amniotic fluid, and low birth weight in the current pregnancy. This trial is registered with ClinicalTrials.gov CTRI/2013/02/003441.

Low birthweight (LBW) and neonatal hyperbilirubinemia (NNH) in an Indian cohort: association of homocysteine, its metabolic pathway genes and micronutrients as risk factors

Background & Aims

Indian subcontinent has the highest child mortality rates along with a very high frequency of low birthweight (LBW). Folate and vitamin B12 (Vit-B12) are necessary during foetal development and their deficiency prevalence in Indians is very high. The objective of the present paper is to assess whether foetal homocysteine (Hcy)/folate metabolic pathway genes, their cofactors and homocysteine level independently (or collectively) predispose children to Low birth weight.

Methods

Cord blood was collected for the study. Frequency of 5 SNPs in 4-Hcy-pathway genes, and levels of Hcy, Vit-B12 and folate were evaluated.

Results

Of the 421 newborns recruited for the study, 38% showed low birth weight (<2.5kg) and 16% were preterm babies. 101 neonates developed neonatal hyperbilirubinemia (NNH). High prevalence of Vit-B12 (65%) and folate (27%) deficiency was observed in newborns along with hyperhomocystinemia (hypHcy-25%). Preterm delivery, micronutrient deficiency, hypHcy and MTHFR 677T SNP are associated as risk factor while G allele of TCN2 C776G is protective against LBW. MTHFR 677T allele and folate deficiency are also independent risk factors for NNH.

Conclusion

We record the highest incidence of Vit-B12, folate deficiency and elevated Hcy levels, of all the studies so far reported on neonates. These together with MTHFR 677T are potential risk factors for LBW. Association of impaired folate/Hcy metabolism with NNH is reported for the first time and the possible way of interaction is discussed. It appears that proper nutritional management during pregnancy would reduce the risk of complex clinical outcomes.

A prospective study of maternal fatty acids, micronutrients and homocysteine and their association with birth outcome

Our earlier studies both in animals and in humans have indicated that micronutrients (folic acid, vitamin B12) and long-chain polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), are interlinked in the one-carbon cycle, which plays an important role in fetal 'programming' of adult diseases. The present study examines the levels of maternal and cord plasma fatty acids, maternal folate, vitamin B12 and homocysteine in healthy mothers at various time points during pregnancy and also examine an association between them. A longitudinal study of 106 normal pregnant women was carried out, and maternal blood was collected at three time points, viz., T1 = 16-20th week, T2 = 26-30th week and T3 = at delivery. Cord blood was collected at delivery. Fatty acids were estimated using a gas chromatograph. Levels of folate, vitamin B12 and homocysteine were estimated by the chemiluminescent microparticle immunoassay (CMIA) technology. Maternal plasma folate (P < 0.05), vitamin B12 (P < 0.01) and DHA (P < 0.05) levels were lowest, while maternal homocysteine levels were highest (P < 0.01) at T3. There was a negative association between maternal DHA and homocysteine at T2 (P < 0.05) and T3 (P < 0.01). There was a positive association between plasma DHA in maternal blood at T3 and cord blood. Furthermore, there was a positive association between maternal folate and vitamin B12 at T3 and baby weight, whereas maternal homocysteine at T1 were inversely associated with baby weight at delivery. Our study provides evidence for the associations of folic acid, vitamin B12, homocysteine with DHA and baby weight, suggesting that a balanced dietary supplementation of folate-vitamin B12-DHA during pregnancy may be beneficial.

Umbilical choline and related methylamines betaine and dimethylglycine in relation to birth weight

BACKGROUND

Low birth weight (LBW) is associated with increased morbidity and mortality for the newborn and risk of chronic disease in adulthood. Choline plays an essential role in the integrity of cell membranes, methylation reactions, and memory development. We examined whether choline, betaine, and dimethylglycine (DMG) concentrations were associated with LBW in Dutch women.

METHODS

Blood was sampled from umbilical cords (UCs) at delivery in singleton pregnancies (n = 1,126). Maternal blood was sampled at 30-34 wk of gestational age (GA) (n = 366). We calculated birth weights standardized for GA and defined LBW as standardized birth weight ≤ 2,500 g.

RESULTS

Maternal concentrations were lower as compared with UC concentrations and were not associated with birth weight. UC choline and betaine were inversely associated with birth weight (β = -60 (-89, -31) and β = -65 (-94, -36), respectively), whereas UC DMG was positively associated with birth weight (β = 35 (6.1, 63)). Odds ratios for LBW were 4.12 (1.15, 14.78), 5.68 (1.24, 25.91), and 0.48 (0.09, 2.65) for the highest UC choline, betaine, and DMG quartiles, respectively, as compared with the lowest quartiles.

CONCLUSION

We observed an increased risk of LBW with increased umbilical choline and betaine in venous UC blood. These results might reflect a change in choline consumption or metabolism or a disturbed placental function.

Low folate status enhances pregnancy changes in plasma betaine and dimethylglycine concentrations and the association between betaine and homocysteine

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). Compared with high folate status, low 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. 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 clinicaltrials.gov as NCT01778205.

Periconceptional folate deficiency and implications in neural tube defects

Nutritional deficiencies are preventable etiological and epigenetic factors causing congenital abnormalities, first cause of infant mortality. Folate deficiency has a well-established teratogenic effect, leading to an increasing risk of neural tube defects. This paper highlights the most recent medical literature about folate deficiency, be it maternal or paternal. It then focuses on associated deficiencies as nutritional deficiencies are multiple and interrelated. Observational and interventional studies have all been consistent with a 50–70% protective effect of adequate women consumption of folates on neural tube defects. Since strategies to modify women's dietary habits and vitamin use have achieved little progress, scientific as well as political effort is mandatory in order to implement global preventive public health strategies aimed at improving the alimentation of women in reproductive age, especially folic acid supplementation. Even with the recent breakthrough of fetal surgery for myelomeningocele, the emphasis should still be on prevention as the best practice rather than treatment of neural tube defects.

Folic acid transport to the human fetus is decreased in pregnancies with chronic alcohol exposure

BACKGROUND

During pregnancy, the demand for folic acid increases since the fetus requires this nutrient for its rapid growth and cell proliferation. The placenta concentrates folic acid into the fetal circulation; as a result the fetal levels are 2 to 4 times higher than the maternal level. Animal and in vitro studies have suggested that alcohol may impair transport of folic acid across the placenta by decreasing expression of transport proteins. We aim to determine if folate transfer to the fetus is altered in human pregnancies with chronic alcohol consumption.

METHODOLOGY/PRINCIPAL FINDINGS

Serum folate was measured in maternal blood and umbilical cord blood at the time of delivery in pregnancies with chronic and heavy alcohol exposure (n = 23) and in non-drinking controls (n = 24). In the alcohol-exposed pairs, the fetal:maternal serum folate ratio was ≤ 1.0 in over half (n = 14), whereas all but one of the controls were >1.0. Mean folate in cord samples was lower in the alcohol-exposed group than in the controls (33.15 ± 19.89 vs 45.91 ± 20.73, p = 0.04).

CONCLUSIONS/SIGNIFICANCE

Our results demonstrate that chronic and heavy alcohol use in pregnancy impairs folate transport to the fetus. Altered folate concentrations within the placenta and in the fetus may in part contribute to the deficits observed in the fetal alcohol spectrum disorders.

Maternal homocysteine and small-for-gestational-age offspring: systematic review and meta-analysis

BACKGROUND

Growth retardation in utero leading to small-for-gestational-age (SGA) newborns is associated with increased neonatal morbidity and mortality and with lifelong consequences such as poor cognitive function and cardiovascular diseases. Maternal total homocysteine (tHcy) concentrations have been linked to a wide range of adverse pregnancy outcomes and could possibly influence birth weight.

OBJECTIVE

We performed a systematic review of and meta-analysis on the association of maternal tHcy and birth weight.

DESIGN

A literature search of English, German, and French publications with the use of the PubMed database (January 1966-July 2010) found 78 abstracts. Search terms were as follows: homocysteine AND (birth weight OR small for gestational age OR intrauterine growth retardation). Studies were eligible if information on maternal tHcy and birth weight and the possible association between maternal tHcy and birth weight was available. Effect size estimates were converted to ORs as estimates of the RR of a woman to deliver SGA offspring when maternal tHcy exceeded the 90th percentile.

RESULTS

The search yielded 19 studies for analysis, consisting of 21,326 individuals. Pooled analysis resulted in a crude OR of 1.25 (95% CI: 1.09, 1.44). When this estimate was expressed as a linear effect, it corresponded to a decrease in birth weight of 31 g (95% CI: -13, -51 g) for a 1-SD increase in maternal tHcy.

CONCLUSIONS

Higher maternal tHcy concentrations are associated with a small increased risk for SGA offspring. The small estimated birth weight difference might be of little clinical relevance for the individual newborn; however, it could be of greater importance at a population level.

Choline and betaine in health and disease

Choline is an essential nutrient, but is also formed by de novo synthesis. Choline and its derivatives serve as components of structural lipoproteins, blood and membrane lipids, and as a precursor of the neurotransmitter acetylcholine. Pre-and postnatal choline availability is important for neurodevelopment in rodents. Choline is oxidized to betaine that serves as an osmoregulator and is a substrate in the betaine-homocysteine methyltransferase reaction, which links choline and betaine to the folate-dependent one-carbon metabolism. Choline and betaine are important sources of one-carbon units, in particular, during folate deficiency. Choline or betaine supplementation in humans reduces concentration of total homocysteine (tHcy), and plasma betaine is a strong predictor of plasma tHcy in individuals with low plasma concentration of folate and other B vitamins (B₂, B₆, and B₁₂) in combination TT genotype of the methylenetetrahydrofolate reductase 677 C->T polymorphism. The link to one-carbon metabolism and the recent availability of food composition data have motivated studies on choline and betaine as risk factors of chronic diseases previously studied in relation to folate and homocysteine status. High intake and plasma level of choline in the mother seems to afford reduced risk of neural tube defects. Intake of choline and betaine shows no consistent relation to cancer or cardiovascular risk or risk factors, whereas an unfavorable cardiovascular risk factor profile was associated with high choline and low betaine concentrations in plasma. Thus, choline and betaine showed opposite relations with key components of metabolic syndrome, suggesting a disruption of mitochondrial choline oxidation to betaine as part of the mitochondrial dysfunction in metabolic syndrome.

Micronutrients and women of reproductive potential: required dietary intake and consequences of dietary deficiency or excess. Part I--Folate, Vitamin B12, Vitamin B6

This two-part review highlights micronutrients for which either public health policy has been established or for which new evidence provides guidance as to recommended intakes during pregnancy. One pivotal micronutrient is folate, the generic name for different forms of a water-soluble vitamin essential for the synthesis of thymidylate and purines and, hence, DNA. For non-pregnant adult women the recommended intake is 400 μg/day dietary folate equivalent. For women capable of becoming pregnant an additional 400 μg/day of synthetic folic acid from supplements or fortified foods is recommended to reduce the risk of neural tube defects (NTD). The average amount of folic acid received through food fortification (grains) in the US is only 128 μg/day, emphasising the need for the supplemental vitamin for women of reproductive age. Vitamin B12 (cobalamin) is a cofactor required for enzyme reactions, including generation of methionine and tetrahydrofolate. B12 is found almost exclusively in foods of animal origin (meats, dairy products); therefore, vegetarians are at greatest risk for dietary vitamin B12 deficiency and should be supplemented. Vitamin B6 is required for many reactions, primarily in amino acid metabolism. Meat, fish and poultry are good dietary sources. Supplementation beyond routine prenatal vitamins is not recommended.

Effects of arsenic on maternal and fetal health

Arsenic, which is commonly found in drinking water, is a potent toxicant, but little is known about its effects on maternal health. Arsenic's modes of action include enzyme inhibition and oxidative stress as well as immune, endocrine, and epigenetic effects. A couple of studies reported increased blood pressure and anemia during pregnancy. Susceptibility to arsenic is dependent on the biomethylation, which occurs via one-carbon metabolism. Methylarsonic acid and dimethylarsinic acid are main metabolites in urine, and elevated methylarsonic acid is considered a general risk factor. Arsenic easily passes the placenta, and a few human studies indicate a moderately increased risk of impaired fetal growth and increased fetal and infant mortality. The fetus and infant are probably partly protected by the increased methylation of arsenic during pregnancy and lactation; the infant is also protected by low arsenic excretion in breast milk. Early-life exposure may induce changes that will become apparent much later in life.

Contribution of fish to intakes of micronutrients important for fetal development: a dietary survey of pregnant women in the Republic of Seychelles

OBJECTIVES

To characterise the diets of pregnant women in the Republic of Seychelles and to determine the contribution of fish to intakes of nutrients important for fetal and neonatal development.

DESIGN

Observational, prospective study.

SETTING

Seychelles Child Development Centre, Mahé, Republic of Seychelles.

SUBJECTS AND METHODS

Pregnant women (n 300) were recruited at their first visit to an antenatal clinic. At 28 weeks' gestation subjects completed a 4 d diet diary (n 273) and intakes were analysed using dietary analysis software.

RESULTS

Mean (sd) energy intake was 9.0 (2.5) MJ/d and fat intakes were higher than UK recommendations for almost two-thirds of the cohort. Fish consumption was lower than in previous surveys, suggesting a move towards a more Westernised diet. Low intakes of a number of nutrients important during pregnancy for fetal development (Fe, Zn, Se and iodine) were observed. However, women who met the current recommendations for these nutrients consumed significantly more fish than those who did not (97 v. 73 g/d).

CONCLUSIONS

The present study highlights the importance of fish in the diet of pregnant Seychellois women for ensuring adequate intakes of micronutrients important in fetal development. Dietary patterns in Seychelles, however, are in a state of transition, with a move towards a Western-style diet as evidenced by higher fat and lower fish intakes. If these dietary trends continue and fish consumption declines further, micronutrient status may be compromised. These findings suggest caution in establishing public health policies that promote limitation of fish intake during pregnancy.

Analysis of betaine and choline contents of aleurone, bran, and flour fractions of wheat (Triticum aestivum L.) Using (1)H nuclear magnetic resonance (NMR) spectroscopy

In conventional milling, the aleurone layer is combined with the bran fraction. Studies indicate that the bran fraction of wheat contains the majority of the phytonutrients betaine and choline, with relatively minor concentrations in the refined flour. This present study suggests that the wheat aleurone layer ( Triticum aestivum L. cv. Tiger) contains the greatest concentration of both betaine and choline (1553.44 and 209.80 mg/100 g of sample, respectively). The bran fraction contained 866.94 and 101.95 mg/100 g of sample of betaine and choline, respectively, while the flour fraction contained 23.30 mg/100 g of sample (betaine) and 28.0 mg/100 g of sample (choline). The betaine content for the bran was lower, and the choline content was higher compared to previous studies, although it is known that there is large variation in betaine and choline contents between wheat cultivars. The ratio of betaine/choline in the aleurone fraction was approximately 7:1; in the bran, the ratio was approximately 8:1; and in the flour fraction, the ratio was approximately 1:1. The study further emphasizes the superior phytonutrient composition of the aleurone layer.

Assessment and interpretation of micronutrient status during pregnancy

Accurate assessment of maternal micronutrient status is critical to the prevention of suboptimal micronutrient status and anaemia during pregnancy. Measurement of Fe, folate and vitamin B12 status is complicated by adaptive changes to maternal and placental physiology that markedly affect concentrations of circulating micronutrients and their functional biomarkers. Validation of new assessment methods by comparison with gold standards is often prevented by ethical considerations. Antenatal screening in the UK is predominantly concerned with the detection of anaemia, although estimation of maternal Fe stores by serum ferritin at the start of antenatal care may be a more effective preventive strategy. Functional assessment of maternal anaemia is highly problematic, so instead reference data are used for its definition. The effect of mild-to-moderate anaemia on pregnancy outcome is unclear because of the crude nature of its assessment and the influence of confounding factors. Fe-deficient erythropoiesis may be detected by assessment of erythrocyte Zn protoporphyrin and reticulocyte Hb, although such measures may be unavailable in many clinical laboratories. Serum soluble transferrin receptor is highly responsive to tissue Fe deficiency and is less affected by inflammation than most other indicators. Direct inter-assay comparison of serum and erythrocyte folate values is inadvisable since recovery rates differ greatly between methods. Serum total homocysteine is a useful functional biomarker of both folate and vitamin B12 status but during pregnancy is influenced by other factors that reduce its sensitivity. Isotope-dilution liquid chromatography-tandem MS and serum holo-transcobalamin provide new opportunities to gain detailed data of folate species and vitamin B12 fractions in large samples.

Breast-feeding protects against arsenic exposure in Bangladeshi infants

BACKGROUND

Chronic arsenic exposure causes a wide range of health effects, but little is known about critical windows of exposure. Arsenic readily crosses the placenta, but the few available data on postnatal exposure to arsenic via breast milk are not conclusive.

AIM

Our goal was to assess the arsenic exposure through breast milk in Bangladeshi infants, living in an area with high prevalence of arsenic-rich tube-well water.

METHODS

We analyzed metabolites of inorganic arsenic in breast milk and infant urine at 3 months of age and compared them with detailed information on breast-feeding practices and maternal arsenic exposure, as measured by concentrations in blood, urine, and saliva.

RESULTS

Arsenic concentrations in breast-milk samples were low (median, 1 microg/kg; range, 0.25-19 microg/kg), despite high arsenic exposures via drinking water (10-1,100 microg/L in urine and 2-40 microg/L in red blood cells). Accordingly, the arsenic concentrations in urine of infants whose mothers reported exclusive breast-feeding were low (median, 1.1 microg/L; range, 0.3-29 microg/L), whereas concentrations for those whose mothers reported partial breast-feeding ranged from 0.4 to 1,520 microg/L (median 1.9 microg/L). The major part of arsenic in milk was inorganic. Still, the infants had a high fraction (median, 87%) of the dimethylated arsenic metabolite in urine. Arsenic in breast milk was associated with arsenic in maternal blood, urine, and saliva.

CONCLUSION

Very little arsenic is excreted in breast milk, even in women with high exposure from drinking water. Thus, exclusive breast-feeding protects the infant from exposure to arsenic.