Vitamin B-12 Status Differs among Pregnant, Lactating, and Control Women with Equivalent Nutrient Intakes

Maternal Vitamin B12 in Pregnancy and Placental Development

Vitamin B12, or cobalamin, is an essential nutrient required for diverse physiological functions secondary to its role as a critical cofactor for two mammalian enzymes, methionine synthase and methylmalonyl-CoA mutase. While essential throughout all life stages, several pathways that require vitamin B12, including hematopoiesis, myelination, and DNA/histone methylation, are particularly critical during pregnancy and fetal development. This narrative review aims to describe vitamin B12 in pregnancy, with emphasis on the placenta's role in ensuring adequate nutrition of the fetus and impacts of vitamin B12 deficiency on placental development and function. Our literature search included preclinical model systems and human cohorts and interventions. Our review identified evidence of B12 deficiency resulting in impaired placental development, greater placental inflammation, and modulation of placental docosahexaenoic acid concentration, collectively suggestive of vitamin B12 deficiency as a determinant of both maternal and fetal health outcomes. Heterogeneity in study design complicated generalization of findings. Future studies should consider selecting a B12 marker that is relatively stable across pregnancy, such as holotranscobalamin, while accounting for important confounders such as maternal folate.

The effects of prenatal and postnatal high-dose vitamin B-12 supplementation on human milk vitamin B-12: a randomized, double-blind, placebo-controlled trial in Tanzania

BACKGROUND

Vitamin B-12 status in human milk (HM) has critical implications for infant growth and development. Few studies have separately evaluated the effects of prenatal and postnatal maternal high-dose vitamin B-12 supplementation on HM vitamin B-12 concentration.

OBJECTIVES

This randomized controlled trial aimed to assess the effects of prenatal and postnatal vitamin B-12 supplementation on HM vitamin B-12 at 6 wk and 7 mo postpartum.

METHODS

Pregnant women were enrolled in Dar es Salaam, Tanzania, between 2001 and 2004. From recruitment (12-27 weeks of gestation) through 6 wk postpartum, participants were randomly assigned to daily oral multiple micronutrient supplementation or placebo. From 6 wk to 18 mo postpartum, a subset of participants was randomly assigned to a postnatal supplement or placebo. The supplement included 50 μg/d of vitamin B-12 and various other vitamins. HM vitamin B-12 concentrations were analyzed at 6 wk and 7 mo postpartum for 412 participants.

RESULTS

The prevalence of HM vitamin B-12 of <310 pmol/L was 73.3% and 68.4% at 6 wk and 7 mo postpartum, respectively. Prenatal supplementation increased HM vitamin B-12 concentration (percent difference: 34.4; 95% CI: 17.0, 54.5; P < 0.001) at 6 wk; this effect was not present at 7 mo. Postnatal supplementation increased HM vitamin B-12 concentration (percent difference: 15.9; 95% CI: 1.91, 31.9; P = 0.025) at 7 mo. Effect modification between prenatal and postnatal supplementation on HM vitamin B-12 status at 7 mo was found, with the effects of prenatal and postnatal supplements more pronounced among those receiving control during the other period; the prenatal supplement had a greater effect with postnatal control, and the postnatal supplement had a greater effect with prenatal control.

CONCLUSIONS

Prenatal maternal vitamin B-12 supplementation has benefits on short-term HM status, and postnatal maternal vitamin B-12 supplementation has benefits on long-term HM status. This trial was registered at clinicaltrials.gov as NCT00197548. https://clinicaltrials.gov/ct2/show/NCT00197548.

Maternal B-vitamin and vitamin D status before, during, and after pregnancy and the influence of supplementation preconception and during pregnancy: Prespecified secondary analysis of the NiPPeR double-blind randomized controlled trial

BACKGROUND

Maternal vitamin status preconception and during pregnancy has important consequences for pregnancy outcome and offspring development. Changes in vitamin status from preconception through early and late pregnancy and postpartum have been inferred from cross-sectional data, but longitudinal data on vitamin status from preconception throughout pregnancy and postdelivery are sparse. As such, the influence of vitamin supplementation on vitamin status during pregnancy remains uncertain. This study presents one prespecified outcome from the randomized controlled NiPPeR trial, aiming to identify longitudinal patterns of maternal vitamin status from preconception, through early and late pregnancy, to 6 months postdelivery, and determine the influence of vitamin supplementation.

METHODS AND FINDINGS

In the NiPPeR trial, 1,729 women (from the United Kingdom, Singapore, and New Zealand) aged 18 to 38 years and planning conception were randomized to receive a standard vitamin supplement (control; n = 859) or an enhanced vitamin supplement (intervention; n = 870) starting in preconception and continued throughout pregnancy, with blinding of participants and research staff. Supplement components common to both treatment groups included folic acid, β-carotene, iron, calcium, and iodine; components additionally included in the intervention group were riboflavin, vitamins B6, B12, and D (in amounts available in over-the-counter supplements), myo-inositol, probiotics, and zinc. The primary outcome of the study was glucose tolerance at 28 weeks' gestation, measured by oral glucose tolerance test. The secondary outcome reported in this study was the reduction in maternal micronutrient insufficiency in riboflavin, vitamin B6, vitamin B12, and vitamin D, before and during pregnancy. We measured maternal plasma concentrations of B-vitamins, vitamin D, and markers of insufficiency/deficiency (homocysteine, hydroxykynurenine-ratio, methylmalonic acid) at recruitment, 1 month after commencing intervention preconception, in early pregnancy (7 to 11 weeks' gestation) and late pregnancy (around 28 weeks' gestation), and postdelivery (6 months after supplement discontinuation). We derived standard deviation scores (SDS) to characterize longitudinal changes among participants in the control group and measured differences between the 2 groups. At recruitment, the proportion of patients with marginal or low plasma status was 29.2% for folate (<13.6 nmol/L), 7.5% and 82.0% for riboflavin (<5 nmol/L and ≤26.5 nmol/L, respectively), 9.1% for vitamin B12 (<221 pmol/L), and 48.7% for vitamin D (<50 nmol/L); these proportions were balanced between the groups. Over 90% of all participants had low or marginal status for one or more of these vitamins at recruitment. Among participants in the control group, plasma concentrations of riboflavin declined through early and late pregnancy, whereas concentrations of 25-hydroxyvitamin D were unchanged in early pregnancy, and concentrations of vitamin B6 and B12 declined throughout pregnancy, becoming >1 SDS lower than baseline by 28 weeks gestation. In the control group, 54.2% of participants developed low late-pregnancy vitamin B6 concentrations (pyridoxal 5-phosphate <20 nmol/L). After 1 month of supplementation, plasma concentrations of supplement components were substantially higher among participants in the intervention group than those in the control group: riboflavin by 0.77 SDS (95% CI 0.68 to 0.87, p < 0.0001), vitamin B6 by 1.07 SDS (0.99 to 1.14, p < 0.0001), vitamin B12 by 0.55 SDS (0.46 to 0.64, p < 0.0001), and vitamin D by 0.51 SDS (0.43 to 0.60, p < 0.0001), with higher levels in the intervention group maintained during pregnancy. Markers of vitamin insufficiency/deficiency were reduced in the intervention group, and the proportion of participants with vitamin D insufficiency (<50 nmol/L) during late pregnancy was lower in the intervention group (35.1% versus 8.5%; p < 0.0001). Plasma vitamin B12 remained higher in the intervention group than in the control group 6 months postdelivery (by 0.30 SDS (0.14, 0.46), p = 0.0003). The main limitation is that generalizability to the global population is limited by the high-resource settings and the lack of African and Amerindian women in particular.

CONCLUSIONS

Over 90% of the trial participants had marginal or low concentrations of one or more of folate, riboflavin, vitamin B12, or vitamin D during preconception, and many developed markers of vitamin B6 deficiency in late pregnancy. Preconception/pregnancy supplementation in amounts available in over-the-counter supplements substantially reduces the prevalence of vitamin deficiency and depletion markers before and during pregnancy, with higher maternal plasma vitamin B12 maintained during the recommended lactational period.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02509988; U1111-1171-8056.

Anthropometric measures and arsenic methylation among pregnant women in rural northern Bangladesh

INTRODUCTION

Arsenic methylation converts inorganic arsenic (iAs) to monomethyl (MMA) and dimethyl (DMA) arsenic compounds. Body mass index (BMI) has been positively associated with arsenic methylation efficiency (higher DMA%) in adults, but evidence in pregnancy is inconsistent. We estimated associations between anthropometric measures and arsenic methylation among pregnant women in rural northern Bangladesh.

METHODS

We enrolled pregnant women (n = 784) (median [IQR] gestational week: 14 [13, 15]) in Gaibandha District, Bangladesh from 2018 to 2019. Anthropometric measures were BMI, subscapular and triceps skinfold thicknesses, and mid-upper arm circumference (MUAC), fat area (MUAFA), and muscle area (MUAMA). Arsenic methylation measures were urinary iAs, MMA, and DMA divided by their sum and multiplied by 100 (iAs%, MMA%, and DMA%), primary methylation index (MMA/iAs; PMI), and secondary methylation index (DMA/MMA; SMI). In complete cases (n = 765 [97.6%]), we fitted linear, beta, and Dirichlet regression models to estimate cross-sectional differences in iAs%, MMA%, DMA%, PMI, and SMI per IQR-unit difference in each anthropometric measure, adjusting for drinking water arsenic, age, gestational age, education, living standards index, and plasma folate, vitamin B12, and homocysteine.

RESULTS

Median (IQR) BMI, subscapular skinfold thickness, triceps skinfold thickness, MUAC, MUAFA, and MUAMA were 21.5 (19.4, 23.8) kg/m2, 17.9 (13.2, 24.2) mm, 14.2 (10.2, 18.7) mm, 25.9 (23.8, 28.0) cm, 15.3 (10.5, 20.3) cm2, and 29.9 (25.6, 34.2) cm2, respectively. Median (IQR) iAs%, MMA%, DMA%, PMI, and SMI were 12.0 (9.3, 15.2)%, 6.6 (5.3, 8.3)%, 81.0 (77.1, 84.6)%, 0.6 (0.4, 0.7), and 12.2 (9.3, 15.7), respectively. In both unadjusted and adjusted linear models, all anthropometric measures were negatively associated with iAs%, MMA%, and PMI and positively associated with DMA% and SMI. For example, fully adjusted mean differences (95% CI) in DMA% per IQR-unit difference in BMI, subscapular skinfolds thickness, triceps skinfold thickness, MUAC, MUAFA, and MUAMA were 1.72 (1.16, 2.28), 1.58 (0.95, 2.21), 1.74 (1.11, 2.37), 1.45 (0.85, 2.06), 1.70 (1.08, 2.31), and 0.70 (0.13, 1.27) pp, respectively.

CONCLUSIONS

Anthropometric measures were positively associated with arsenic methylation efficiency among pregnant women in the early second trimester.

Vitamin B12 Deficiency (Un-)Detected Using Newborn Screening in Norway

Untreated vitamin B12 (B12) deficiency may cause delayed development in infants. Several newborn screening (NBS) programs have reported an increased detection rate of B12 deficiency when second-tier dried blood spot (DBS) analyses of total homocysteine (tHcy) and methylmalonic acid (MMA) are included. This is a retrospective study of newborns reported from NBS during 2012−2021 with confirmed B12 deficiency. DBSs were retrieved from the NBS biobank for second-tier MMA and tHcy analysis. Thirty-one newborns were diagnosed with B12 deficiency out of 552970 screened. Twenty-five were ascertained from sixty-one false positive (FP) cases of methylmalonic acidemia and propionic acidemia (PA), and six infants screened positive for other NBS metabolic diseases with propionylcarnitine (C3) in the normal range. In the original DBS, 7/23 (30%) and 12/23 (52%) of B12-deficient newborns with FP methylmalonic acidemia/PA had MMA and tHcy > 99th percentile. B12 deficiency was a common differential diagnosis of screening positive for methylmalonic and PA. C3 failed to identify a subset of newborns with B12 deficiency. Second-tier MMA and tHcy analyses in the DBS showed suboptimal sensitivity for identifying infants with B12 deficiency. The shortcomings of NBS should be acknowledged when considering B12 deficiency as a primary target of NBS panels.

Maternal serum concentrations of one-carbon metabolism factors modify the association between biomarkers of arsenic methylation efficiency and birth weight

BACKGROUND

Inorganic arsenic (iAs) is a ubiquitous metalloid and drinking water contaminant. Prenatal exposure is associated with birth outcomes across multiple studies. During metabolism, iAs is sequentially methylated to mono- and di-methylated arsenical species (MMAs and DMAs) to facilitate whole body clearance. Inefficient methylation (e.g., higher urinary % MMAs) is associated with increased risk of certain iAs-associated diseases. One-carbon metabolism factors influence iAs methylation, modifying toxicity in adults, and warrant further study during the prenatal period. The objective of this study was to evaluate folate, vitamin B12, and homocysteine as modifiers of the relationship between biomarkers of iAs methylation efficiency and birth outcomes.

METHODS

Data from the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort (2011-2012)  with maternal urine and cord serum arsenic biomarkers and maternal serum folate, vitamin B12, and homocysteine concentrations were utilized. One-carbon metabolism factors were dichotomized using clinical cutoffs and median splits. Multivariable linear regression models were fit to evaluate associations between each biomarker and birth outcome overall and within levels of one-carbon metabolism factors. Likelihood ratio tests of full and reduced models were used to test the significance of statistical interactions on the additive scale (α = 0.10).

RESULTS

Among urinary biomarkers, % U-MMAs was most strongly associated with birth weight (β = - 23.09, 95% CI: - 44.54, - 1.64). Larger, more negative mean differences in birth weight were observed among infants born to women who were B12 deficient (β = - 28.69, 95% CI: - 53.97, - 3.42) or experiencing hyperhomocysteinemia (β = - 63.29, 95% CI: - 154.77, 28.19). Generally, mean differences in birth weight were attenuated among infants born to mothers with higher serum concentrations of folate and vitamin B12 (or lower serum concentrations of homocysteine). Effect modification by vitamin B12 and homocysteine was significant on the additive scale for some associations. Results for gestational age were less compelling, with an approximate one-week mean difference associated with C-tAs (β = 0.87, 95% CI: 0, 1.74), but not meaningful otherwise.

CONCLUSIONS

Tissue distributions of iAs and its metabolites (e.g., % MMAs) may vary according to serum concentrations of folate, vitamin B12 and homocysteine during pregnancy. This represents a potential mechanism through which maternal diet may modify the harms of prenatal exposure to iAs.

Evidence based recommendations for an optimal prenatal supplement for women in the US: vitamins and related nutrients

The blood levels of most vitamins decrease during pregnancy if un-supplemented, including vitamins A, C, D, K, B1, B3, B5, B6, folate, biotin, and B12. Sub-optimal intake of vitamins from preconception through pregnancy increases the risk of many pregnancy complications and infant health problems. In the U.S., dietary intake of vitamins is often below recommended intakes, especially for vitamin D, choline and DHA. Many studies suggest that insufficient vitamin intake is associated with a wide range of pregnancy complications (anemia, Cesarean section, depression, gestational diabetes, hypertension, infertility, preeclampsia, and premature rupture of membranes) and infant health problems (asthma/wheeze, autism, low birth weight, congenital heart defects, intellectual development, intrauterine growth restriction, miscarriage, neural tube defects, orofacial defects, and preterm birth). The primary goal of this paper is to review the research literature and propose evidence-based recommendations for the optimal level of prenatal supplementation for each vitamin for most women in the United States. A secondary goal was to compare these new recommendations with the levels of vitamins in over 180 commercial prenatal supplements. The analysis found that prenatal supplements vary widely in content, often contained only a subset of essential vitamins, and the levels were often below our recommendations. This suggests that increasing prenatal vitamin supplementation to the levels recommended here may reduce the incidence of many pregnancy complications and infant health problems which currently occur.

Maternal Mental Health in Late Pregnancy and Longitudinal Changes in Postpartum Serum Vitamin B-12, Homocysteine, and Milk B-12 Concentration Among Brazilian Women

Background

Little is known regarding the association between mental health distress during pregnancy and postpartum maternal serum biomarkers of vitamin B-12 status and milk B-12 concentration.

Objective

To evaluate the association between depressive and anxiety symptoms in the third trimester of pregnancy and changes in postpartum serum B-12, homocysteine, and B-12 milk concentration.

Methods

A total of 101 women (18–40 years) were studied in a prospective cohort with data at the third trimester of pregnancy (baseline) and three postpartum time-points (TPs): 2–8 days (TP1), 28–50 days (TP2), and 88-119 days (TP3) postpartum. B-12 concentrations in milk were measured by competitive chemiluminescent enzyme immunoassay at TP1, TP2, and TP3. Serum B-12 and homocysteine concentrations were evaluated at baseline, TP1, TP2, and TP3 by chemiluminescent immunoassays. Depressive and anxiety symptoms were measured with the Edinburgh Postnatal Depression Scale and the State-Trait Anxiety Inventory at baseline. Spearman's correlation test and multiple linear mixed-effect models were performed.

Results

The prevalence of depressive and anxiety state symptoms was 35.6 and 39.6% at baseline. High prevalence of low milk B-12 concentration (<310 pmol/L) were observed at TP1 (53.2%), TP2 (71.4%), and TP3 (71.1%). Women with anxiety symptoms at baseline presented higher median concentrations of serum homocysteine at TP1 and lower concentrations of serum and milk B-12 at TP2 compared with women without anxiety symptoms [8 (7; 9) vs. 6 (5; 8) and 266 (188; 369) vs. 332 (272; 413)]. Milk B-12 concentrations were positively and significantly correlated with maternal serum B-12 concentrations at different TP. Women with anxiety symptoms at baseline exhibited a decrease in daily postpartum homocysteine concentrations compared to women without anxiety symptoms (β = −0.002, SE = 0.001, p = 0.024).

Conclusion

Anxiety symptoms at the end of pregnancy were associated with longitudinal changes in maternal serum homocysteine concentrations during the first 3 months postpartum.

Evaluating the Diagnostic Value of a Combined Indicator of Vitamin B12 Status (cB12) Throughout Pregnancy

Background

Inadequate provision of vitamin B₁₂ during pregnancy is associated with a number of adverse maternal and fetal outcomes. We set out to (1) suggest pregnancy-specific reference ranges for a range of biomarkers of vitamin B₁₂; (2) assess the temporal behaviors of these markers over the course of pregnancy; and (3) test whether any biomarkers, including the genetic marker HIBCH rs291466 strongly associated with MMA measured early in pregnancy could reliably and significantly predict future B₁₂ status within a healthy UK population of pregnant women.

Materials and Methods

We used existing biobank samples from the placebo arm of the UK Selenium in PRegnancy Intervention (SPRINT) study, to generate biochemical data for serum folate, B₁₂, holotranscobalamin (HoloTC), total homocysteine (tHcy), and MMA, calculate cB₁₂, and genotyped the polymorphism rs291466 in gene HIBCH on a total of n=114 women across trimesters 1–3 of their pregnancy. We performed a series of exploratory cross-sectional and longitudinal analyses to investigate levels at each trimester, suggest references ranges, evaluate changes and correlations between the B₁₂ biomarkers, and assess the predictive capabilities of each biomarker from 12-weeks to 35-weeks of gestation.

Results

Significant changes in all vitamin B₁₂ biomarker values were observed over the three trimesters (P < 0.05). Our study shows that cB₁₂ values were largely constant and stable throughout trimester 1 (T1) and T2 (i.e., up to week 20), but declined significantly in T3 (−66% | P < 0.001). Yet, cB₁₂ generally remained within the normal boundaries. We identified pregnancy and trimester-specific reference ranges for each biomarker at each trimester, notably for total serum B₁₂. This marker fell below the recommended cut-offs in 1/3 of the cohort at the third trimester, contrasting other markers (mostly normal). Our multivariate analyses indicated that none of the biomarkers could reliably and accurately predict any other biomarkers than themselves later in pregnancy. Yet, HoloTC seems to be a promising predictor within the limitations of our cohort, constituted of B₁₂-replete individuals. Most notably, cB₁₂ did not significantly predict itself between trimesters. Finally, we show that the HIBCH variant has little predictive power for MMA or cB₁₂ as it does not explain the significant increase in MMA concentrations nor the decline of cB₁₂ throughout pregnancy.

Conclusion

Trimester-specific reference ranges for biomarkers of vitamin B₁₂ in normal pregnancy are suggested. However, these biomarkers have limited predictive value in identifying mothers at elevated risk of vitamin B₁₂ insufficiency/deficiency during pregnancy.

Limited data exist to inform our basic understanding of micronutrient requirements in pregnancy

Women and pregnant people have historically been underrepresented in research; this may extend to the basic research informing nutrient reference values, such as the United States’ and Canada’s Dietary Reference Intakes (DRIs). After screening the DRI reports for 23 micronutrients, we extracted metadata from 704 studies. Women were excluded in 23% of studies, and they accounted for a smaller proportion of the sample size (29%). Pregnant or lactating people were included in 17% of the studies. Studies that used rigorous design elements, such as controlled feeding and stable isotope studies, were the most likely to include men only. The majority of studies (>90%) did not report race and ethnicity. Although nutrient reference values are intended for use in the general population, we find that the basic science informing these values may not be generalizable. We call urgently upon funders and researchers to address fundamental gaps in knowledge with high-quality research.

Reference intervals for serum total vitamin B12 and holotranscobalamin concentrations and their change points with methylmalonic acid concentration to assess vitamin B12 status during early and mid-pregnancy

Background Maternal vitamin B12 (B-12) adequacy is important for maternal health and optimal fetal growth. However, pregnancy-specific cut-offs for B-12 biomarkers are lacking. Methods Reference intervals for serum total B-12, holotranscobalamin (holoTC) and methylmalonic acid (MMA) concentrations were calculated following CLSI EP28-A3c guidelines in 723 pregnant women of European (50%) and South Asian (50%) ethnicity, residing in British Columbia, Canada, at median (range) 11.4 (8.3-13.9) and 16.1 (14.9-20.9) weeks of gestation. Change point analyses described relationships between log serum MMA concentration with serum total B-12 and holoTC concentrations, assuming linear-linear relationships. Results The central 95% reference interval limits indicated that serum total B-12 <89.9 and <84.0 pmol/L, holoTC <29.5 and <26.0 pmol/L and MMA >371 and >374 nmol/L, in the first and second trimesters, respectively, may indicate B-12 deficiency in pregnant women. The lower limits of total B-12 and holoTC and the upper limits of MMA significantly differed by ethnicity in both trimesters. According to the change point analysis, total B-12 <186 and <180 pmol/L and holoTC <62.2 and <67.5 pmol/L in the first and second trimesters, respectively, suggested an increased probability of impaired intracellular B-12 status, with no difference between ethnicities. Conclusions We present novel reference limits and change points for B-12 biomarkers, which may be employed to identify possible B-12 deficiency in women during early and mid-pregnancy. Future research is needed to validate these cut-offs and determine the predictors and functional outcomes associated with impaired B-12 status in ethnically diverse populations.

Vitamin B12 is Low in Milk of Early Postpartum Women in Urban Tanzania, and was not Significantly Increased by High dose Supplementation

The effect of maternal multivitamin supplementation on breast milk vitamin B12 concentrations has not been examined in Tanzania, where the prevalence of maternal plasma B12 insufficiency is 25.6%. Multivitamins (containing 50 µg vitamin B12) or placebo were provided during pregnancy and in the postpartum period. Breast milk samples were collected at or around six weeks postpartum from 491 participants in a trial of multivitamins (NCT00197548). Linear and logistic regression models were used to examine the effect of supplements on vitamin B12 concentration in milk and its associations with other variables including potential confounders. Median vitamin B12 concentration in breast milk was 206 pmol/L and 70% of women had levels indicating inadequacy (<310 pmol/L). Multivitamin supplements did not significantly reduce the odds of inadequate vitamin B12 in breast milk, suggesting suboptimal absorption. A single unit increase in maternal hemoglobin at six weeks was associated with 18% lower odds of inadequate vitamin B12 in breast milk. Participants with higher BMI at baseline had double the odds of having inadequate vitamin B12 than the reference group (<22 kg/m2). Trials to determine the optimal dose, route, and duration of supplementation to improve maternal B12 status in Sub-Saharan Africa are of utmost importance.

Depression and Anxiety: Lack of Associations with an Inadequate Diet in a Sample of Pregnant Women with a History of Bariatric Surgery-a Multicenter Prospective Controlled Cohort Study

BACKGROUND

Anxiety and depression levels are higher in obese compared to those in normal weight pregnant women. The aims of this study are to examine anxiety and depression in pregnancy following bariatric surgery and to compare with obese pregnant controls considering the dietary intake of polyunsaturated fatty acids (PUFA), folate, and vitamin B₁₂.

METHODS

Anxiety (State-Trait Anxiety Inventory) and depression (Edinburgh Postnatal Depression Scale) were examined in the first (T1) and third (T3) pregnancy trimester in 54 women with bariatric surgery and 25 obese. T1 and T3 dietary intake of PUFA, folate, and vitamin B₁₂ intake was assessed using a 3-day food record. Mixed models with a compound symmetry covariance structure and regression models were applied.

RESULTS

About half of the women with surgery had high state and trait anxiety scores (≥ 40), which did not significantly change during pregnancy. Every 10-kg postoperative weight loss was associated with an increase in T1 state and trait anxiety with respectively 2.7 and 2.3 points. A smoking woman had a 8.6-point higher state anxiety score than a non-smoking woman in T1. In T3, every additional hour of sleep was associated with a decrease in trait anxiety score with 1.59 points. Anxiety and depression scores were not associated with and could not be explained by inadequate PUFAs, folate, and vitamin B₁₂ intakes. Anxiety scores were higher following surgery than those in untreated obesity at both time points.

CONCLUSION

Pregnancy following bariatric surgery induces high levels of anxiety that are not associated with an inadequate maternal diet.

Public Health Aspects in the Prevention and Control of Vitamin Deficiencies

Vitamin deficiencies remain major etiological factors in the global burden of disease, especially in low- and middle-income countries. The purpose of this state-of-the-art review was to update current information on deficiencies of vitamins and public health approaches to addressing them. Some stages of life present a higher risk of deficiency than others: risks are higher in pregnant women, children (from conception to young childhood), adolescents, the elderly, and all of the over 800 million people globally who are undernourished. At risk are approximately 125 million preschool children with vitamin A deficiency, as well as sub-populations at risk of deficiencies of folate, thiamin, vitamin B12, niacin, riboflavin, other B vitamins. and vitamin D. Addressing micronutrient deficiencies requires identifying those at risk and then working to prevent and manage that risk. Public health approaches include improved, diversified diets; supplementation; fortification and biofortification; and other supportive public health measures. Historically, as with pellagra and beriberi and, in the last 3 decades, with vitamin A and folic acid, there has been encouraging progress, but much remains to be done.

Maternal choline supplementation alters vitamin B-12 status in human and murine pregnancy

Despite participation in overlapping metabolic pathways, the relationship between choline and vitamin B-12 has not been well characterized especially during pregnancy. We sought to determine the effects of maternal choline supplementation on vitamin B-12 status biomarkers in human and mouse pregnancy, hypothesizing that increased choline intake would improve vitamin B-12 status. Associations between common genetic variants in choline-metabolizing genes and vitamin B-12 status biomarkers were also explored in humans. Healthy third-trimester pregnant women (n=26) consumed either 480 or 930 mg choline/day as part of a 12-week controlled feeding study. Wild-type NSA and Dlx3 heterozygous (Dlx3+/-) mice, which display placental insufficiency, consumed a 1×, 2× or 4× choline diet and were sacrificed at gestational days 15.5 and 18.5. Serum vitamin B-12, methylmalonic acid (MMA) and homocysteine were measured in all samples; holotranscobalamin (in humans) and hepatic vitamin B-12 (in mice) were also measured. The 2× choline supplementation for 12 weeks in pregnant women yielded higher serum concentrations of holotranscobalamin, the bioactive form of vitamin B-12 (~24%, P=.01). Women with genetic variants in choline dehydrogenase (CHDH) and betaine-homocysteine S-methyltransferase (BHMT) had higher serum MMA concentrations (~31%, P=.03) and lower serum holotranscobalamin concentrations (~34%, P=.03), respectively. The 4× choline dose decreased serum homocysteine concentrations in both NSA and Dlx3+/- mice (~36% and~43% respectively, P≤.015). In conclusion, differences in choline supply due to supplementation or genetic variation modulate vitamin B-12 status during pregnancy, supporting a functional relationship between these nutrients.

Vitamin B-12 in Human Milk: A Systematic Review

Despite the critical role of vitamin B-12 in infant development, existing recommendations for infant and maternal intake during lactation are based on milk vitamin B-12 concentrations analyzed with outdated methods in a sample of 9 Brazilian women. Accurate quantification of vitamin B-12 in the milk matrix requires effective hydrolysis of the vitamin from haptocorrin, its binding protein. The objective of the present systematic review is to consider and critique evidence of associations between milk vitamin B-12 concentration and time postpartum, maternal vitamin B-12 consumption, maternal vitamin B-12 status, and sample collection methodology. A systematic search of published literature was undertaken using the US National Library of Medicine's MEDLINE/PubMed bibliographic search engine. Observational and intervention studies were included if research was original and vitamin B-12 concentration in human milk was measured using an appropriate method during the first 12 mo of lactation. Eleven studies met inclusion criteria. Vitamin B-12 concentration was highest in colostrum and decreased in a poorly delineated trajectory over the first 3-4 mo of lactation. There was some evidence of a positive association between habitual maternal vitamin B-12 intake and milk vitamin B-12 concentration in marginally nourished women. Supplementation with 50-250 µg vitamin B-12/d during pregnancy and lactation raised human milk vitamin B-12 concentrations while intervention was ongoing, whereas supplementation with 2.6-8.6 µg/d was effective in a population with poor baseline vitamin B-12 status but not in other populations. Whether milk vitamin B-12 concentration varies with maternal circulating vitamin B-12 concentrations or sampling methodology requires further research as existing data are conflicting. Additional research is needed to bridge knowledge gaps in the understanding of human milk vitamin B-12 concentrations. Reference values for vitamin B-12 in human milk and recommended intakes during infancy and lactation should be reevaluated using modern methods of analysis.

Maternal Serum Cobalamin at 18 Weeks of Pregnancy Predicts Infant Cobalamin Status at 6 Months-A Prospective, Observational Study

Background

An adequate maternal cobalamin status is crucial for fetal and infant neurodevelopment. Pregnancy-induced physiologic changes make evaluation of maternal cobalamin status in pregnancy difficult.

Objective

We have investigated maternal cobalamin status during pregnancy in order to establish a maternal cobalamin concentration which secures an optimal infant cobalamin status during the first 6 mo of life.

Methods

In an observational, prospective study, markers of cobalamin status including serum cobalamin, plasma total homocysteine (tHcy), and plasma methylmalonic acid (MMA) were assessed in healthy pregnant women (n = 114) from week 18 of pregnancy through 6 mo postpartum and related to infant cobalamin status at 6 mo. Healthy, never-pregnant women aged 18-40 y (n = 123) were included as controls.

Results

Compared to controls, all markers of cobalamin status were lower in pregnant women. Median serum cobalamin concentration progressively decreased from week 18 to week 36 of pregnancy (356 to 302 pmol/L, P < 0.001) and increased by >40% by 6 wk postpartum (518 pmol/L). The metabolic markers increased from week 18 of pregnancy to 6 wk postpartum: median plasma tHcy 3.9 to 7.7 μmol/L (P < 0.001), and MMA 0.13 to 0.17 μmol/L (P < 0.001). The serum cobalamin concentration of infants at age 6 mo correlated with maternal serum cobalamin concentration during pregnancy and postpartum (rho = 0.36-0.55, P < 0.001). A maternal serum cobalamin concentration <394 pmol/L during week 18 of pregnancy was associated with an increased risk (OR: 4.2; 95% CI: 1.5, 11.5) of infant biochemical cobalamin deficiency at 6 mo (defined as tHcy ≥6.5 μmol/L).

Conclusions

The maternal serum cobalamin concentration in early pregnancy is a strong predictor for later maternal and infant cobalamin status. To secure an optimal infant cobalamin status during the first 6 mo of life, we recommend a maternal serum cobalamin concentration >394 pmol/L at week 18 of pregnancy. This should be confirmed in an intervention study. This trial was registered at clinicaltrials.gov as NCT03272022.

Micronutrients in Human Milk: Analytical Methods

Exclusive breastfeeding is recommended by the WHO for the first 6 mo of life because human milk protects against gastrointestinal infections and supplies balanced and adequate nutrient contents to the infant. However, reliable data on micronutrient concentrations in human milk are sparse, especially because some micronutrients are affected by maternal diet. Microbiological and competitive protein-binding assays, nuclear magnetic resonance or inductively coupled plasma spectroscopy, and chromatographic analyses are among the methods that have been applied to human-milk micronutrient analysis. However, the validation or evaluation of analytical methods in terms of their suitability for the complex human-milk matrix has been commonly ignored in reports, even though the human-milk matrix differs vastly from blood, plasma, or urine matrixes. Thus, information on the validity, accuracy, and sensitivity of the methods is essential for the estimation of infant and maternal intake requirements to support and maintain adequate milk micronutrient concentrations for healthy infant growth and development. In this review, we summarize current knowledge on methods used for analyzing water- and fat-soluble vitamins as well as iron, copper, zinc, iodine, and selenium in human milk and their different forms in milk; the tools available for quality control and assurance; and guidance for preanalytical considerations. Finally, we recommend preferred methodologic approaches for analysis of specific milk micronutrients.

Should vitamin B12 status be considered in assessing risk of neural tube defects?

There is a strong biological premise for including vitamin B₁₂ with folic acid in strategies to prevent neural tube defects (NTDs), due to the closely interlinked metabolism of these two vitamins. For example, reduction of B₁₂ deficiency among women of reproductive age could enhance the capacity of folic acid to prevent NTDs by optimizing the cellular uptake and utilization of natural folate cofactors. Vitamin B₁₂ might also have an independent role in NTD prevention, such that adding it in fortification programs might be more effective than fortifying with folic acid alone. Globally, there is ample evidence of widespread vitamin B₁₂ deficiency in low‐ and middle‐income countries, but there is also considerable divergence of vitamin B₁₂ status across regions, likely due to genetic as well as nutritional factors. Here, I consider the evidence that low vitamin B₁₂ status may be an independent factor associated with risk of NTDs, and whether a fortification strategy to improve B₁₂ status would help reduce the prevalence of NTDs. I seek to identify knowledge gaps in this respect and specify research goals that would address these gaps.

Population Reference Values for Serum Methylmalonic Acid Concentrations and Its Relationship with Age, Sex, Race-Ethnicity, Supplement Use, Kidney Function and Serum Vitamin B12 in the Post-Folic Acid Fortification Period

Serum methylmalonic acid (MMA) is elevated in vitamin B-12 deficiency and in kidney dysfunction. Population reference values for serum MMA concentrations in post-folic acid fortification period are lacking. Aims of this study were to report the population reference values for serum MMA and to evaluate the relation between serum MMA and sex, age, race-ethnicity, kidney dysfunction and vitamin B-12. We used data from three National Health and Nutrition Examination Surveys, 1999–2000, 2001–2002 and 2003–2004 conducted after folic acid fortification commenced (n = 18,569). Geometric mean MMA was ≈22.3% higher in non-Hispanic white compared to non-Hispanic black (141.2 vs. 115.5 nmol/L) and was ≈62.7% higher in >70 years old persons compared to 21–30 years old persons (196.9 vs. 121.0 nmol/L). Median serum MMA was ≈28.5% higher in the 1st the quartile of serum vitamin B-12 than in the 4th quartile of serum vitamin B-12 and was ≈35.8% higher in the 4th quartile of serum creatinine than in the 1st quartile of serum creatinine. Multivariate-adjusted serum MMA concentration was significantly associated with race-ethnicity (p < 0.001) and age (p < 0.001) but not with sex (p = 0.057). In this large US population based study, serum MMA concentrations presented here reflect the post-folic acid fortification scenario. Serum MMA concentrations begin to rise at the age of 18–20 years and continue to rise afterwards. Age-related increase in serum MMA concentration is likely to be due to a concomitant decline in kidney function and vitamin B-12 status.

Cobalamin Status from Pregnancy to Early Childhood: Lessons from Global Experience

Low cobalamin intake and status during pregnancy or lactation have been linked to adverse maternal and perinatal health outcomes, whereas low cobalamin status during early childhood is associated with impaired development in children. Women who begin pregnancy with depleted stores (low or very low plasma cobalamin) will give birth to depleted infants who are likely to develop deficiency symptoms during the first few weeks or months postpartum. Newly ingested cobalamin during pregnancy and lactation (from diet or supplements) is transferred to the child and is not likely to correct cobalamin status in depleted women. The prevalence of low cobalamin status is high especially in low-income settings or in populations with a low intake of animal products. Folate and cobalamin play interdependent roles in one-carbon metabolism. Although folic acid supplementation during early pregnancy is widely recommended and practiced, cobalamin supplementation during pregnancy and lactation has received little attention. Furthermore, the intake recommendations for pregnant and lactating women and in early life need reevaluation in the light of newly available evidence in the field.

Vitamin B12 deficiency

Vitamin B₁₂ (B12; also known as cobalamin) is a B vitamin that has an important role in cellular metabolism, especially in DNA synthesis, methylation and mitochondrial metabolism. Clinical B12 deficiency with classic haematological and neurological manifestations is relatively uncommon. However, subclinical deficiency affects between 2.5% and 26% of the general population depending on the definition used, although the clinical relevance is unclear. B12 deficiency can affect individuals at all ages, but most particularly elderly individuals. Infants, children, adolescents and women of reproductive age are also at high risk of deficiency in populations where dietary intake of B12-containing animal-derived foods is restricted. Deficiency is caused by either inadequate intake, inadequate bioavailability or malabsorption. Disruption of B12 transport in the blood, or impaired cellular uptake or metabolism causes an intracellular deficiency. Diagnostic biomarkers for B12 status include decreased levels of circulating total B12 and transcobalamin-bound B12, and abnormally increased levels of homocysteine and methylmalonic acid. However, the exact cut-offs to classify clinical and subclinical deficiency remain debated. Management depends on B12 supplementation, either via high-dose oral routes or via parenteral administration. This Primer describes the current knowledge surrounding B12 deficiency, and highlights improvements in diagnostic methods as well as shifting concepts about the prevalence, causes and manifestations of B12 deficiency.

Vitamin Concentrations in Human Milk Vary with Time within Feed, Circadian Rhythm, and Single-Dose Supplementation

Background: Human milk is the subject of many studies, but procedures for representative sample collection have not been established. Our improved methods for milk micronutrient analysis now enable systematic study of factors that affect its concentrations.Objective: We evaluated the effects of sample collection protocols, variations in circadian rhythms, subject variability, and acute maternal micronutrient supplementation on milk vitamin concentrations.Methods: In the BMQ (Breast-Milk-Quality) study, we recruited 18 healthy women (aged 18-26 y) in Dhaka, Bangladesh, at 2-4 mo of lactation for a 3-d supplementation study. On day 1, no supplements were given; on days 2 and 3, participants consumed ∼1 time and 2 times, respectively, the US-Canadian Recommended Dietary Allowances for vitamins at breakfast (0800-0859). Milk was collected during every feeding from the same breast over 24 h. Milk expressed in the first 2 min (aliquot I) was collected separately from the remainder (aliquot II); a third aliquot (aliquot III) was saved by combining aliquots I and II. Thiamin, riboflavin, niacin, and vitamins B-6, B-12, A, and E and fat were measured in each sample.Results: Significant but small differences (14-18%) between aliquots were found for all vitamins except for vitamins B-6 and B-12. Circadian variance was significant except for fat-adjusted vitamins A and E, with a higher contribution to total variance with supplementation. Between-subject variability accounted for most of the total variance. Afternoon and evening samples best reflected daily vitamin concentrations for all study days. Acute supplementation effects were found for thiamin, riboflavin, and vitamins B-6 and A at 2-4 h postdosing, with 0.1-6.17% passing into milk. Supplementation was reflected in fasting, 24-h postdose samples for riboflavin and vitamin B-6. Maximum amounts of dose-responding vitamins in 1 feeding ranged from 4.7% to 21.8% (day 2) and 8.2% to 35.0% (day 3) of Adequate Intake.Conclusions: In the milk of Bangladeshi mothers, differences in vitamin concentrations between aliquots within feedings and by circadian variance were significant but small. Afternoon and evening collection provided the most-representative samples. Supplementation acutely affects some breast-milk micronutrient concentrations. This trial was registered at clinicaltrials.gov as NCT02756026.

A Prospective Study on Serum Methylmalonic Acid and Homocysteine in Pregnant Women

This study aimed to investigate serum methylmalonic acid (MMA) and homocysteine levels and to assess their effects on pregnancy and neonatal outcomes. Serum MMA and homocysteine levels in 278 pregnant Korean women, determined by liquid chromatography–tandem mass spectrometry in each trimester, were compared with those of previous studies in other ethnic groups. We investigated the association between MMA and homocysteine status with pregnancy and neonatal events: gestational diabetes, preeclampsia, gestational age at delivery, preterm birth, small for gestational age, neonatal birth weight, and congenital abnormalities. The median (range) MMA level was 0.142 (0.063–0.446) µmol/L and homocysteine level was 10.6 (4.4–38.0) µmol/L in pregnant women. MMA levels were significantly higher in the third trimester than during other trimesters (p < 0.05), while homocysteine levels were not. No significant association was observed between MMA or homocysteine levels and any of the maternal or neonatal outcomes examined. Future studies are needed to assess the associations among maternal serum concentrations of MMA and homocysteine, and maternal and neonatal outcomes.

Cross-sectional study of nutritional markers in pregnancy

OBJECTIVES

To note the value of serum Vitamin B12, folic acid, and ferritin in normal and high-risk pregnancies (HRPs) in patients attending antenatal clinic at All India Institute of Medical Sciences (AIIMS).

MATERIALS AND METHODS

This is a cross-sectional study where a total of 282 patients attending Gynaecology Outpatient Department at AIIMS, New Delhi, India were recruited. Among the 282 subjects, 251 were pregnant, and 31 were controls. The serum was tested for serum Vitamin B12, serum folic acid, and serum ferritin levels using Beckman Coulter Access 2 immunoassay.

RESULTS

The median value of serum folic acid level in pregnant women was 12 pg/ml with range being 2-20 pg/ml in contrast to 8 pg/ml with range being 3-20 pg/ml in nonpregnant female. This difference was statistically significant. (P = 0.05). There was no significant difference in the median level of serum Vitamin B12 and serum ferritin in pregnant and nonpregnant group. Serum Vitamin B12 level was lower in the third trimester (127 pg/ml) than in first trimester (171 pg/ml) and the difference is statistically significant (P = 0.03). Serum ferritin levels were also significantly lower in the second trimester (16.4 pg/ml) than third trimester (24.55 pg/ml). Although the median serum folic acid level was lower in the first trimester (9.84 pg/ml) than in second trimester (10.8 pg/ml) and in the third trimester (13.18 pg/ml) but the difference was not statistically significant. There was no significant difference in Vitamin B12 level in HRPs (median value 134 pg/ml) as compared to low-risk pregnancies (149.5 pg/ml).

CONCLUSION

Serum folic acid levels are significantly higher during pregnancy as compared to nonpregnant state. However, there was no significant difference in the median level of serum Vitamin B12 and serum ferritin in pregnant and nonpregnant group. Serum folic acid level and ferritin level were significantly higher in HRPs compared to low-risk pregnancies.

Vitamin B12 status in women of childbearing age in the UK and its relationship with national nutrient intake guidelines: results from two National Diet and Nutrition Surveys

OBJECTIVE

To assess serum B12, folate and the associated homocysteine (Hcy) levels among women of childbearing age in the UK and examine their association with dietary intake in relation to the UK Recommended Nutrient Intakes (RNIs) for B12 and folate.

DESIGN

Cross-sectional study.

SETTING

Data from two publicly available National Diet and Nutrition Surveys (NDNS 2000/2001 and 2008/2012) were used. These were population-based surveys of randomly selected samples of adults which were carried out in their households.

PARTICIPANTS

Women of childbearing age (aged 19-39 years), representative of the UK population. Those who were pregnant or breastfeeding were excluded.

OUTCOME MEASURES

The associations between micronutrient intakes and blood levels of B12, folate and Hcy were assessed by correlation and stepwise linear regression. B12 intake was divided into quintiles and plotted against blood B12 and Hcy concentrations to determine the threshold of any associations.

RESULTS

299 women from the first NDNS cohort had complete intake and biomarker data. The prevalence of serum vitamin B12 (≤150 pmol/L) and serum folate (≤10 nmol/L) deficiency and hyperhomocysteinemia (≥12 µmol/L) was 12.4%, 6.4% and 21.2%, respectively, despite seemingly adequate B12 intakes (median 3.8 μg/day, 96% consumed more than the UK RNI of 1.5 μg/day). B12 concentrations increased across all quintiles of intake with serum levels in quintiles 4 and 5 (median intake 4.9 and 7.1 μg/day, respectively) significantly higher than quintile 1. However, Hcy concentrations levelled off between quintiles 4 and 5. Comparison of micronutrient intake between the two surveys found that folate intake has reduced in the more recent cohort.

CONCLUSIONS

The UK RNI for B12 intake should be increased for women of childbearing age with intakes of around 5-7 μg/day likely to be associated with stable biomarker levels. B12 levels should also be measured in women preconceptionally or in early pregnancy given the high rates of deficiency.

Low Serum Vitamin B-12 Concentrations Are Prevalent in a Cohort of Pregnant Canadian Women

BACKGROUND

Among Canadian women of reproductive age, 5% and 20% have serum vitamin B-12 concentrations indicative of deficiency (<148 pmol/L) and marginal status (148-220 pmol/L), respectively. Given the association between suboptimal vitamin B-12 and adverse pregnancy outcomes, an understanding of vitamin B-12 status during pregnancy, and factors that influence it, is required.

OBJECTIVE

This prospective analysis from the PREFORM (PREnatal FOlic acid exposuRe on DNA Methylation in the newborn infant) study investigated 1) vitamin B-12 status in a cohort of Canadian pregnant women and their newborns, 2) the association of maternal dietary vitamin B-12 intake with maternal and cord blood concentrations of vitamin B-12 and its biomarkers, and 3) the association of fetal genetic polymorphisms with cord blood concentrations of vitamin B-12 and its biomarkers.

METHODS

In pregnant Canadian women (n = 368; mean ± SD age: 32 ± 5 y), vitamin B-12 intakes were assessed in early (0-16 wk) and mid- to late (23-37 wk) pregnancy. Serum vitamin B-12 and plasma total homocysteine (tHcy) and methylmalonic acid (MMA) in maternal blood at 12-16 wk of pregnancy and at delivery (28-42 wk) and in cord blood were measured and compared by using regression analyses. The associations of 28 fetal genetic variants in vitamin B-12 metabolism and cord blood vitamin B-12, tHcy, and MMA concentrations were assessed by using regression analysis, with adjustment for multiple testing.

RESULTS

A total of 17% and 38% of women had deficient and 35% and 43% had marginal serum vitamin B-12 concentrations at 12-16 wk of pregnancy and at delivery, respectively. Only 1.9-5.3% had elevated MMA (>271 nmol/L), and no women had elevated tHcy (>13 μmol/L). Maternal dietary vitamin B-12 intake during pregnancy was either weakly associated or not associated with maternal and cord blood vitamin B-12 (r(2) = 0.17-0.24, P < 0.0008), tHcy (P = NS) and MMA (r(2) = 0.05-0.11, P < 0.001). Fetal genetic polymorphisms were not associated with cord blood concentrations of vitamin B-12 and its biomarkers.

CONCLUSIONS

Deficient and marginal serum vitamin B-12 concentrations are prevalent in Canadian pregnant women with the use of traditional cutoffs, despite supplement use. Given the growing interest among women to adhere to a vegetarian diet that may be lower in vitamin B-12, and vitamin B-12's importance in pregnancy, the functional ramifications of these observations need to be elucidated. This trial was registered at clinicaltrials.gov as NCT02244684.