Maternal MTHFR 677C>T genotype and dietary intake of folate and vitamin B(12): their impact on child neurodevelopment

Role of one-carbon nutrient intake and diabetes during pregnancy in children's growth and neurodevelopment: A 2-year follow-up study of a prospective cohort

BACKGROUND & AIMS

Both maternal metabolic dysregulation, e.g., gestational diabetes mellitus (GDM), and maternal supply of nutrients that participate in one-carbon (1C) metabolism, e.g., folate, choline, betaine, and vitamin B12, have been demonstrated to influence epigenetic modification such as DNA methylation, thereby exerting long-lasting impacts on growth and development of offspring. This study aimed to determine how maternal 1C nutrient intake was associated with DNA methylation and further, development of children, as well as whether maternal GDM status modified the association in a prospective cohort.

METHODS

In this study, women with (n = 18) and without (n = 20) GDM were recruited at 25-33 weeks gestation. Detailed dietary intake data was collected by 3-day 24-h dietary recall and nutrient levels in maternal blood were also assessed at enrollment. The maternal-child dyads were invited to participate in a 2-year follow-up during which anthropometric measurement and the Bayley Scales of Infant and Toddler Development™ Screening Test (Third Edition) were conducted on children. The association between maternal 1C nutrients and children's developmental outcomes was analyzed with a generalized linear model controlling for maternal GDM status.

RESULTS

We found that children born to mothers with GDM had lower scores in the language domain of the Bayley test (p = 0.049). Higher maternal food folate and choline intakes were associated with better language scores in children (p = 0.01 and 0.025, respectively). Higher maternal food folate intakes were also associated with better cognitive scores in children (p = 0.002). Higher 1C nutrient intakes during pregnancy were associated with lower body weight of children at 2 years of age (p < 0.05). However, global DNA methylation of children's buccal cells was not associated with any maternal 1C nutrients.

CONCLUSIONS

In conclusion, higher 1C nutrient intake during pregnancy was associated with lower body weight and better neurodevelopmental outcomes of children. This may help overcome the lower language scores seen in GDM-affected children in this cohort. Studies in larger cohorts and with a longer follow-up duration are needed to further delineate the relationship between prenatal 1C nutrient exposure, especially in GDM-affected pregnancies, and offspring health outcomes.

Prenatal Vitamin B12 and Children's Brain Development and Cognitive, Language and Motor Outcomes: A Scoping Review

Adequate maternal nutrient intake of vitamin B12 is critical to fetal brain development and subsequent neurodevelopmental outcomes. We conducted a scoping review to map the current state of knowledge from human epidemiological studies on the associations between maternal vitamin B12 during pregnancy and children's brain, cognitive, language, and motor development to identify gaps in the literature and suggest directions for future research. PubMed and OVID MEDLINE were searched. Search terms were vitamin B12, prenatal or maternal, neurodevelopment or cognitive development or brain. Animal studies were excluded. In total, 148 publications were identified, of which 19 met our inclusion criteria: (1) maternal vitamin B12 assessed via a measure of status, dietary intake, supplementation, or deficiency; and (2) an outcome related to brain development or cognitive, language, or motor development in children less than 18 years of age was assessed. This scoping review suggests that evidence supporting a relationship between maternal vitamin B12 during pregnancy and children's neurodevelopmental outcomes is inconclusive. Further longitudinal research is needed to clarify the effects of maternal vitamin B12 supplementation, status, and intake on children's brain development and neurodevelopmental outcomes.

Associations between maternal folate status and choline intake during pregnancy and neurodevelopment at 3-4 years of age in the Alberta Pregnancy Outcomes and Nutrition (APrON) study

Folate and choline are methyl donor nutrients that may play a role in fetal brain development. Animal studies have reported that prenatal folate and choline supplementation are associated with better cognitive outcomes in offspring and that these nutrients may interact and affect brain development. Human studies that have investigated associations between maternal prenatal folate or choline levels and neurodevelopmental outcomes have reported contradictory findings and no human studies have examined the potential interactive effect of folate and choline on children's neurodevelopment. During the second trimester of pregnancy, maternal red blood cell folate was measured from blood samples and choline intake was estimated using a 24-h dietary recall in 309 women in the APrON cohort. At 3-5 years of age, their children's neurodevelopment was assessed using the Wechsler Preschool and Primary Scales of Intelligence - Fourth EditionCND, NEPSY-II language and memory subtests, four behavioral executive function tasks, and the Movement Assessment Battery for Children - Second Edition. Adjusted regressions revealed no associations between maternal folate and choline levels during pregnancy and most of the child outcomes. On the Dimensional Change Card Sort, an executive function task, there was an interaction effect; at high levels of choline intake (i.e., 1 SD above the mean; 223.03 mg/day), higher maternal folate status was associated with decreased odds of receiving a passing score (β = -0.44; 95%CI -0.81, -0.06). In conclusion, maternal folate status and choline intake during the second trimester of pregnancy were not associated with children's intelligence, language, memory, or motor outcomes at 3-4 years of age; however, their interaction may have an influence children's executive functions.

Maternal Serum Vitamin B12 during Pregnancy and Offspring Autism Spectrum Disorder

This study examined the association between maternal serum vitamin B12 levels during early pregnancy and offspring autism spectrum disorders (ASD) and subtypes. Based on a Finnish national birth cohort, case offspring (n = 1558) born in 1987-2007 and diagnosed with ASD by 2015 were matched with one control on date of birth, sex and place of birth. Maternal vitamin B12 levels were measured during first and early second trimesters of pregnancy. High maternal vitamin B12 levels (≥81th percentile) was associated with increased risk for offspring childhood autism, adjusted odds ratio, 1.59, 95% confidence interval 1.06-2.41 (p = 0.026). No significant associations were observed between maternal vitamin B12 levels and offspring Asperger's or pervasive developmental disorder/NOS.

Maternal Vitamin B12 Status during Pregnancy and Early Infant Neurodevelopment: The ECLIPSES Study

In this prospective cohort study of 434 mother-infant pairs from the ECLIPSES study, we examine the association between maternal vitamin B12 status at the beginning and end of pregnancy and the neurodevelopmental outcomes of infants 40 days after birth in a pregnant population from a Mediterranean region of northern Spain. Maternal vitamin B12 concentrations were determined in the first and third trimesters, and sociodemographic, nutritional, and psychological data were collected. At 40 days postpartum, the Bayley Scales of Infant Development-III (BSID-III, cognitive, language, and motor skills) were administered to the infants and several obstetrical data were recorded. In the multivariable models, medium maternal first-trimester vitamin B12 levels (312 to 408 pg/mL, tertile 2) were associated with better neonatal performance in the motor, gross motor, language, and cognitive skills with respect to tertile 1 (<312 pg/mL). The probability of obtaining a neonatal motor, gross motor, and receptive language score >75th percentile was significantly higher also in the tertile 2 group. In summary, good maternal vitamin B12 status in the early stage of pregnancy appears to be associated with better infant motor, language, and cognitive performance at 40 days postpartum.

Association between the Use of Folic Acid Supplements during Pregnancy and Children's Cognitive Function at 7-9 Years of Age in the INMA Cohort Study

This study investigated the association between maternal low (<400 μg/day) or high (≥1000 μg/day) folic acid supplements (FAs) use during pregnancy and the attentional function and working memory in boys and girls at age 7-9. A longitudinal analysis based on 1609 mother-child pairs from the Spanish Infancia y Medio Ambiente Project was carried out. Multivariable regression analyses revealed that, compared to the recommended FAs use, a low FAs use during the second period of pregnancy was associated with a lower alertness in all children (β = 18.70 ms; 95% CI: 7.51; 29.89) and in girls (β = 30.01 ms; 95% CI: 12.96; 47.01), and with a lower N-back Task performance in boys (d' number 2-back (β = -0.25; 95% CI: -0.49; 0.01)). A high FAs use throughout the two periods of pregnancy was associated with a better N-back Task performance only in girls (d' number 2-back (β = 0.28; 95% CI: 0.01; 0.56) and d' number 3-back (β = 0.32; 95% CI: 0.08; 0.56)). The maternal use of FAs beyond the periconceptional period may affect children's attentional function and working memory at age 7-9 differently for boys and girls.

Association of Maternal Vitamin B12 Status With Infant Findings and Neurodevelopment in Vitamin B12-Deficient Breast-fed Babies

Few studies have examined the association between maternal vitamin B12 status and their breast-fed infants' findings. The objective of this study was to analyze the association of maternal B12 status with infant findings including neurodevelopmental outcome in breast-fed babies with B12 deficiency. Correlation analyses between the laboratory findings of infants with B12 deficiency (n=120) and their mothers were performed and the association of maternal B12 status with infant findings including the Denver-II developmental screening test (DDST II) results was examined. There was a significant correlation between infant and maternal B12 levels (r=0.222; P=0.030), and between infant and maternal homocysteine (Hcy) levels (r=0.390; P<0.001). Among the babies 4 months of age or older, maternal Hcy levels were significantly correlated with infant mean corpuscular hemoglobin (r=0.404; P=0.001) and infant mean corpuscular volume (r=0.461; P<0.001). Mothers of infants with abnormal DDST II had lower vitamin B12 (196.9±41.2 vs. 247.0±77.0 pg/mL; P=0.018) and higher Hcy levels (17.3±5.0 vs. 10.7±3.1 µmol/L; P<0.001) than mothers of infants with normal DDST II. A lower maternal vitamin B12 status may be related to impaired neurodevelopment in breast-fed infants with vitamin B12 deficiency. Pregnant and lactating women should be offered easy access to healthy nutrition and vitamin B12 supplements.

Neurodevelopmental effects of maternal folic acid supplementation: a systematic review and meta-analysis

Folic acid, a water-soluble vitamin B nutrient, plays an important role not only in maintaining a healthy pregnancy but also in offspring brain development and function, however, it remains unclear whether maternal folic acid (FA) supplementation associated with the risk of different postnatal neurodevelopmental outcomes. Here, we performed a systematic review and meta-analysis on the impact of maternal FA supplementation on a wide range of postnatal neurodevelopmental outcomes which include intellectual development, risk of autistic traits, ADHD, behavior, language, and psychomotor problems, using studies extracted from the following databases, including MEDLINE, Web of Science, Cochrane Library, Scopus, EMBASE, and PsychInfo. Thirty-two cohort studies and seven case-control studies were included in this meta-analysis. In the present study, we found that prenatal FA supplementation had a positive impact on offspring's neurodevelopmental outcomes, including improved intellectual development and reduced risk of autism traits, ADHD, behavioral, and language problems. We also found that FA over-supplementation was not associated with an improvement in offspring's brain development, and may have a negative impact on offspring's neurodevelopmental outcomes. This study proved the first panoramic review on the relationship of FA supplementation with offspring's neurodevelopment. Further studies focusing on different dosages and periods of FA supplementation are needed.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1993781 .

One carbon metabolism and early development: a diet-dependent destiny

One carbon metabolism (OCM) is critical for early development, as it provides one carbon (1C) units for the biosynthesis of DNA, proteins, and lipids and epigenetic modification of the genome. Epigenetic marks established early in life can be maintained and exert lasting impacts on gene expression and functions later in life. Animal and human studies have increasingly demonstrated that prenatal 1C nutrient deficiencies impair fetal growth, neurodevelopment, and cardiometabolic parameters in childhood, while sufficient maternal 1C nutrient intake is protective against these detrimental outcomes. However, recent studies also highlight the potential risk of maternal 1C nutrient excess or imbalance in disrupting early development. Further studies are needed to delineate the dose-response relationship among prenatal 1C nutrient exposure, epigenetic modifications, and developmental outcomes.

The Use of Lower or Higher Than Recommended Doses of Folic Acid Supplements during Pregnancy Is Associated with Child Attentional Dysfunction at 4-5 Years of Age in the INMA Project

We assessed the association between the use of lower- and higher-than-recommended doses of folic acid supplements (FAs) during pregnancy and attentional function in boys and girls at age of 4–5. We analyzed data from 1329 mother-child pairs from the mother-child cohort INfancia y Medio Ambiente Project (INMA) study. Information on FAs use during pregnancy was collected in personal interviews at weeks 12 and 30, and categorized in <400, 400–999 (recommended dose), and ≥1000 μg/day. Child attentional function was assessed by Conners’ Kiddie Continuous Performance Test. Multivariable regression analyses were used to estimate incidence rate ratios (IRR) and beta coefficients with 95% confidence intervals (CI). Compared to recommended FAs doses, the periconceptional use of <400 and ≥1000 μg/day was associated with higher risk of omission errors—IRR = 1.14 (95% CI: 1.01; 1.29) and IRR = 1.16 (95% CI: 1.02; 1.33), respectively. The use of FAs < 400 μg/day and ≥1000 μg/day was significantly associated with deficits of attentional function only in boys. FAs use < 400 μg/day was associated with higher omission errors with IRR = 1.22 and increased hit reaction time (HRT) β = 34.36, and FAs use ≥ 1000 μg/day was associated with increased HRT β = 33.18 and HRT standard error β = 3.31. The periconceptional use of FAs below or above the recommended doses is associated with deficits of attentional function in children at age of 4–5, particularly in boys.

Pre-conceptional Maternal Vitamin B12 Supplementation Improves Offspring Neurodevelopment at 2 Years of Age: PRIYA Trial

Background: The first thousand days window does not include the pre-conceptional period. Maternal pre-conceptional health has a profound influence on early embryonic development (implantation, gastrulation, placentation etc). Nutrition provided by B-complex vitamins is important for fetal growth, especially neural development. We report effects of a maternal pre-conceptional vitamin B12 and multi micronutrient (MMN) supplementation on offspring neurodevelopmental performance. Methods: In the Pune Rural Intervention in Young Adolescents trial (PRIYA), adolescents (N = 557, 226 females) were provided with vitamin B12 (2 μg/day) with or without multiple micronutrients, or a placebo, from preconception until delivery. All groups received mandatory iron and folic acid. We used the Bayley's Scale of Infant Development (BSID-III) at 24-42 months of age to investigate effects on offspring neurodevelopment. Results: Participants had similar baseline B12 levels. The levels improved in the B12 supplemented groups during pre-conception and pregnancy (28 weeks gestation), and were reflected in higher cord blood holotranscobalamin (holo-TC) levels compared to the placebo group. Neurodevelopmental outcomes in the B12 alone group (n = 21) were better than the placebo (n = 27) in cognition (p = 0.044) and language (p = 0.020) domains (adjusted for maternal baseline B12 levels). There was no difference in neurodevelopmental outcomes between the B12 + MMN (n = 26) and placebo group. Cord blood Brain Derived Neurotrophic Factor (BDNF) levels were highest in the B12 alone group, though not significant. Conclusion: Pre-conceptional vitamin B12 supplementation improved maternal B12 status and offspring neurodevelopment at 2 years of age. The usefulness of cord BDNF as a marker of brain development needs further investigation. Our results highlight the importance of intervening during pre-conception.

Long-Chain Polyunsaturated Fatty Acids, Homocysteine at Birth and Fatty Acid Desaturase Gene Cluster Polymorphisms are Associated with Children's Processing Speed up to Age 9 Years

Both pre- and early postnatal supplementation with docosahexaenoic acid (DHA), arachidonic acid (AA) and folate have been related to neural development, but their long-term effects on later neural function remain unclear. We evaluated the long-term effects of maternal prenatal supplementation with fish-oil (FO), 5-methyltetrahydrofolate (5-MTHF), placebo or FO + 5-MTHF, as well as the role of fatty acid desaturase (FADS) gene cluster polymorphisms, on their offspring’s processing speed at later school age. This study was conducted in NUHEAL children at 7.5 (n = 143) and 9 years of age (n = 127). Processing speed tasks were assessed using Symbol Digit Modalities Test (SDMT), Children Color Trails Test (CCTT) and Stroop Color and Word Test (SCWT). Long-chain polyunsaturated fatty acids, folate and total homocysteine (tHcy) levels were determined at delivery from maternal and cord blood samples. FADS and methylenetetrahydrofolate reductase (MTHFR) 677 C > T genetic polymorphisms were analyzed. Mixed models (linear and logistic) were performed. There were significant differences in processing speed performance among children at different ages (p < 0.001). The type of prenatal supplementation had no effect on processing speed in children up to 9 years. Secondary exploratory analyses indicated that children born to mothers with higher AA/DHA ratio at delivery (p < 0.001) and heterozygotes for FADS1 rs174556 (p < 0.05) showed better performance in processing speed at 9 years. Negative associations between processing speed scores and maternal tHcy levels at delivery were found. Our findings suggest speed processing development in children up to 9 years could be related to maternal factors, including AA/DHA and tHcy levels, and their genetic background, mainly FADS polymorphism. These considerations support that maternal prenatal supplementation should be quantitatively adequate and individualized to obtain better brain development and mental performance in the offspring.

Maternal prenatal vitamin B12 intake is associated with speech development and mathematical abilities in childhood

Deficiencies of many nutrients in pregnancy have adverse effects on fetal brain development with consequent impaired cognitive function in childhood. However, it is unclear whether deficiencies of vitamin B12 prenatally are harmful to the developing fetus. We therefore used the Avon Longitudinal Study of Parents and Children to test the hypothesis that cognitive outcomes in childhood are reduced if their mothers consumed a diet low in vitamin B12 during pregnancy. A detailed exposome analysis was used to identify 9 factors independently associated with low vitamin B12 intake. These were taken into account in each of 26 outcome analyses. Results showed that the children of women with the lowest 10% intake of B12 were at increased risk of poor vocabulary at 24 months, reduced ability at combining words at 38 months, poor speech intelligibility at 6 years, poor mathematics comprehension at school years 4 and 6 (ages 8-9 and 10-11 years), and poor results on the national mathematics tests (age 13). There were no such significant adjusted associations for reading or spelling abilities, or for verbal or full-scale IQ (Intelligence Quotient) at 8 or at 15. Thus, we have confirmed that there are adverse effects on the child's development if the pregnant woman has a low intake of vitamin B12, and we have shown that these are specific to certain speech and mathematical abilities.

A Meta-Analysis of Stressors from the Total Environment Associated with Children's General Cognitive Ability

General cognitive ability, often referred to as ‘general intelligence’, comprises a variety of correlated abilities. Childhood general cognitive ability is a well-studied area of research and can be used to predict social outcomes and perceived success. Early life stage (e.g., prenatal, postnatal, toddler) exposures to stressors (i.e., chemical and non-chemical stressors from the total (built, natural, social) environment) can impact the development of childhood cognitive ability. Building from our systematic scoping review (Ruiz et al., 2016), we conducted a meta-analysis to evaluate more than 100 stressors related to cognitive development. Our meta-analysis identified 23 stressors with a significant increase in their likelihood to influence childhood cognitive ability by 10% or more, and 80 stressors were observed to have a statistically significant effect on cognitive ability. Stressors most impactful to cognition during the prenatal period were related to maternal health and the mother’s ability to access information relevant to a healthy pregnancy (e.g., diet, lifestyle). Stressors most impactful to cognition during the early childhood period were dietary nutrients (infancy), quality of social interaction (toddler), and exposure to toxic substances (throughout early childhood). In conducting this analysis, we examined the relative impact of real-world exposures on cognitive development to attempt to understand the inter-relationships between exposures to both chemical and non-chemical stressors and early developmental life stages. Our findings suggest that the stressors observed to be the most influential to childhood cognitive ability are not permanent and can be broadly categorized as activities/behaviors which can be modified to improve childhood cognition. This meta-analysis supports the idea that there are complex relationships between a child’s total environment and early cognitive development.

Efficacy of maternal B12 supplementation in vegetarian women for improving infant neurodevelopment: protocol for the MATCOBIND multicentre, double-blind, randomised controlled trial

INTRODUCTION

Vitamin B12 deficiency is widely prevalent across many low- and middle-income countries, especially where the diet is low in animal sources. While many observational studies show associations between B12 deficiency in pregnancy and infant cognitive function (including memory, language and motor skills), evidence from clinical trials is sparse and inconclusive.

METHODS AND ANALYSIS

This double-blind, multicentre, randomised controlled trial will enrol 720 vegetarian pregnant women in their first trimester from antenatal clinics at two hospitals (one in India and one in Nepal). Eligible mothers who give written consent will be randomised to receive either 250 mcg methylcobalamin or 50 mcg (quasi control), from enrolment to 6 months post-partum, given as an oral daily capsule. All mothers and their infants will continue to receive standard clinical care. The primary trial outcome is the offspring's neurodevelopment status at 9 months of age, assessed using the Development Assessment Scale of Indian Infants. Secondary outcomes include the infant's biochemical B12 status at age 9 months and maternal biochemical B12 status in the first and third trimesters. Maternal biochemical B12 status will also be assessed in the first trimester. Modification of association by a priori identified factors will also be explored.

ETHICAL CONSIDERATIONS AND DISSEMINATION

The study protocol has been approved by ethical committees at each study site (India and Nepal) and at University College London, UK. The study results will be disseminated to healthcare professionals and academics globally via conferences, presentations and publications. Researchers at each study site will share results with participants during their follow-up visits.Trial registration numberCTRI/2018/07/015048 (Clinical Trial Registry of India); NCT04083560 (ClinicalTrials.gov).

Facts and hypotheses about the programming of neuroplastic deficits by prenatal malnutrition

Studies in rats have shown that a decrease in either protein content or total dietary calories results in molecular, structural, and functional changes in the cerebral cortex and hippocampus, among other brain regions, which lead to behavioral disturbances, including learning and memory deficits. The neurobiological bases underlying those effects depend at least in part on fetal programming of the developing brain, which in turn relies on epigenetic regulation of specific genes via stable and heritable modifications of chromatin. Prenatal malnutrition also leads to epigenetic programming of obesity, and obesity on its own can lead to poor cognitive performance in humans and experimental animals, complicating understanding of the factors involved in the fetal programming of neuroplasticity deficits. This review focuses on the role of epigenetic mechanisms involved in prenatal malnutrition-induced brain disturbances, which are apparent at a later postnatal age, through either a direct effect of fetal programming on brain plasticity or an indirect effect on the brain mediated by the postnatal development of obesity.

The association of prenatal folate and vitamin B12 levels with postnatal neurodevelopment varies by maternal MTHFR 677C>T genotype

Prenatal folate and vitamin B12 status have been linked to child neuropsychological development, but less is known about maternal genetic influences on this association. We conducted an exploratory longitudinal study of 181 mother–child pairs to assess whether maternal MTHFR 677C>T genotype modifies the association between maternal plasma folate and vitamin B12 in the first trimester of pregnancy and child neuropsychological development. Maternal plasma folate and vitamin B12 were determined by radioimmunoassay, and MTHFR 677C>T genotypes by PCR. We evaluated child neuropsychological development at 1, 3, 6, 12, 18, 24, and 30 month old using the Bayley Scales of Infant Development II. We analyzed the data using mixed-effects multivariate linear regression. The MTHFR 677C>T genotype distribution among the mothers was 18.2% CC, 49.8% CT, and 32.0% TT. The Mental Development Index (MDI) was inversely associated with maternal plasma folate among offspring of MTHFR 677CC mothers (β = -2.18 per twofold increase, 95% CI -4.07; -0.30, corrected P value = 0.02); no significant associations were observed among children born to women of other genotypes. The Motor Development Index (PDI) was not significantly associated with maternal plasma folate in any maternal MTHFR 677C>T genotype group, nor were MDI or PDI significantly associated with maternal plasma vitamin B12 in any maternal MTHFR 677C>T genotype group. This study suggests that maternal MTHFR 677CC genotype interacts with first-trimester plasma folate to influence offspring mental development.

The Importance of Maternal Folate Status for Brain Development and Function of Offspring

The importance of an adequate periconceptional maternal folate status to prevent fetal neural tube defects has been well demonstrated and resulted in the recommendation for women to use folic acid supplements during the periconception period. The importance of maternal folate status for offspring neurodevelopment and brain health is less well described. We reviewed the current evidence linking maternal folate status before conception and during pregnancy with neurodevelopment and cognition of the offspring. We discuss both animal and human studies. Preclinical research revealed the importance of maternal folate status for several key processes required for normal neurodevelopment and brain functioning in the offspring, including DNA synthesis, regulation of gene expression, synthesis of phospholipids and neurotransmitters, and maintenance of healthy plasma homocysteine concentrations. Human observational studies are inconclusive; about half have shown a positive association between maternal folate status and cognitive performance of offspring. Whereas some studies suggest a positive association between maternal folate intake and cognition of offspring during childhood, data from interventional studies are too limited to conclude that there is a direct effect. Future preclinical studies are needed to help us characterize the behavioral effects, understand the underlying mechanisms, and to establish an optimal dosage and time window of folate supplementation. Moreover, more conclusive data from well-designed human observational studies and randomized controlled trials are needed to determine whether current recommendations for folic acid supplementation during pregnancy cover the needs for normal cognitive development in the offspring.

Maternal plasma vitamin B12 concentrations during pregnancy and infant cognitive outcomes at 2 years of age

Evidence on long-term influences of maternal vitamin B12 deficiency or concentrations on infant cognition is limited. We examined associations between maternal plasma vitamin B12 and cognitive development in 24-month-old infants. Maternal plasma vitamin B12 concentrations were measured at 26-28 weeks' gestation; infant cognitive development was assessed with the Bayley Scales of Infant and Toddler Development-III at 24 months, for 443 mother-infant pairs from the Growing Up in Singapore Towards Healthy Outcomes cohort. Linear regressions adjusted for key confounders examined associations of maternal vitamin B12 with cognitive, receptive and expressive language, fine and gross motor subscales. Co-occurrence of maternal vitamin B12 with folate or vitamin B6 insufficiencies on child's cognition was explored. Average maternal plasma vitamin B12 concentrations was 220·5 ± 80·5 pmol/l; 15 % and 41 % of mothers were vitamin B12 deficient (&lt;148 pmol/l) and insufficient (148-220·9 pmol/l), respectively. Infants of mothers with vitamin B12 deficiency had 0·42 (95 % CI -0·70, -0·14) sd lower cognitive scores, compared with infants of mothers with sufficient vitamin B12. Co-occurrence of maternal vitamins B12 and B6 insufficiencies was associated with 0·37 (95 % CI -0·69, -0·06) sd lower cognitive scores in infants compared with infants of mothers sufficient in both vitamins. No significant associations were observed with other subscales. Study findings suggest the possible need to ensure adequate vitamin B12 during pregnancy. The impact of co-occurrence of maternal B-vitamins insufficiencies on early cognitive development warrants further investigation.

Effect of Maternal Vitamin B12 Supplementation on Cognitive Outcomes in South Indian Children: A Randomized Controlled Clinical Trial

Objectives To examine the effects of oral maternal vitamin B12 supplementation during pregnancy and early lactation on cognitive development in children. Method We studied 218 children born to mothers enrolled in a placebo-controlled, randomized trial of vitamin B12 supplementation during pregnancy through 6 weeks post-partum. Cognitive functions were assessed at 30 months using the Bayley Scales of Infant Development- 3rd edition (BSID III). The association of maternal sociodemographic characteristics, maternal biochemical status during pregnancy, birth weight and home environment with each sub-domain of BSID-III was examined using linear regression analysis. Separate multiple linear regression analyses for each of the BSID-III sub-domains with maternal trimester specific nutritional biomarker status was conducted. Results Children of mothers who received oral vitamin B12 supplementation had significantly higher scores on expressive language compared to children of mothers who received placebo (β = 0.14, P = 0.03). Children of mothers with elevated serum total homocysteine (tHcy) in the second and third trimesters of pregnancy had significantly lower scores on expressive language (β = - 0.18, P = 0.03 and β = - 0.19, P = 0.02, respectively) and gross motor domains (β = - 0.23, P = 0.008 and β = - 0.30, P = 0.001, respectively) of BSID-III adjusted for treatment arm and multiple confounders, compared with children whose mothers did not have elevated tHcy. Conclusions for practice Maternal B12 supplementation during pregnancy was associated with higher expressive language scores in children at 30 months. Elevated maternal tHcy levels during pregnancy had negative associations with expressive language and gross motor domains of BSID-III. Larger trials of maternal B12 supplementation are needed to confirm these findings.

Effects of maternal B12 supplementation on neurophysiological outcomes in children: a study protocol for an extended follow-up from a placebo randomised control trial in Bangalore, India

INTRODUCTION

Vitamin B12 deficiency is highly prevalent in pregnant Indian women. Neuropsychological tests have shown an association between low maternal vitamin B12 status and poorer cognitive performances in the offspring, although findings from these studies have been inconsistent. Vitamin B12 has an important role in the formation of myelin which is important for the transmission speed of neural impulses and myelination in the central nervous system has been linked to cognition. Assessing neurophysiological measures using event-related potentials (ERPs) in children may provide additional information on the effect of maternal vitamin B12 supplementation on offspring brain function. The study examines the effects of oral vitamin B12 daily supplements (50 µg) to pregnant Indian women on child neurophysiological function at 72 months.

METHODS AND ANALYSIS

We previously conducted a double-blind, placebo-controlled study to examine the effects of maternal vitamin B12 supplementation on cognitive outcomes in their offspring using the Bayley scales of infant development, third edition. In this extended follow-up of the same cohort of mother-child dyad, we propose to use ERP to study the long-term impact of maternal B12 supplementation on brain function in children at 72 months of age. We intend to use P300 and mismatch negativity (MMN) as measures of neurophysiological outcomes. The primary outcome of this study will be child neurophysiological measures (as measured by amplitude and latency of P300 and MMN) assessed at 72 months of age in children whose mothers received vitamin B12 compared with neurophysiological status of children whose mothers received placebo.

ETHICS AND DISSEMINATION

The study was approved by the Institutional Ethical Board of St. John's Medical College and the Harvard School of Public Health Human Subjects Committee. Results obtained will be presented at national and international research meetings and published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

NCT00641862.

Maternal folate nutrition and offspring health: evidence and current controversies

Periconceptional folic acid (FA) is known to have a protective effect in the prevention of neural tube defects (NTD), leading to global recommendations for FA supplementation before and in early pregnancy. Maternal folate throughout pregnancy may have other roles in offspring health, including neurodevelopment and cognitive performance in childhood. Folate is essential for C1 metabolism, a network of pathways involved in several biological processes including nucleotide synthesis, DNA repair and methylation reactions. The evidence reviewed here shows a conclusive role for offspring health of maternal folate nutrition in early pregnancy and probable benefits in later pregnancy. Folate-mediated epigenetic changes in genes related to brain development and function offer a plausible biological basis to link maternal folate with effects in offspring brain, albeit this research is in its infancy. Mandatory FA fortification of food has proven to be highly effective in decreasing NTD cases in populations where it has been implemented, but this policy is controversial owing to concerns related to potential adverse effects of over-exposure to FA. In the absence of population-wide fortification, and given the generally poor compliance with current FA recommendations, optimising folate status of mothers in very early pregnancy for protection against NTD remains challenging. Thus, current policy in the UK, Ireland and elsewhere in Europe for the prevention of NTD (based on periconceptional FA supplementation only), has proven to be largely ineffective. This review addresses the evidence and the controversies that surround this area, as well as identifying the challenges in translating policy into practice.

Child dietary intake of folate and vitamin B12 and their neurodevelopment at 24 and 30 months of age

OBJECTIVE

To evaluate whether child dietary intake of folate and vitamin B12, is associated with mental and psychomotor development in Mexican children, respectively, at 24 and 30 months of age.

MATERIALS AND METHODS

Information about neurodevelopment and dietary intake of folate and vitamin B12 at 24 and 30 months of age among 229 children belonging to a perinatal cohort was analyzed longitudinally. Dietary information was assessed using a semi-quantitative food frequency questionnaire, and neurodevelopment by Bayley Scale of Infant Development II.

RESULTS

At 30 months of age, dietary folate intake was marginally associated with increased Mental Development Index (MDI) (b=8.33; 95%CI -0.48, 17.14; p=0.06). Nonsignificant positive associations of vitamin B12 with MDI were found. Psychomotor Development Index (PDI) was not associated with these nutrients.

CONCLUSIONS

Dietary folate intake in early childhood may benefit the mental development of children.

Exploring a causal role of DNA methylation in the relationship between maternal vitamin B12 during pregnancy and child's IQ at age 8, cognitive performance and educational attainment: a two-step Mendelian randomization study

An adequate intake of vitamin B₁₂ during pregnancy plays an important role in offspring neurodevelopment, potentially via epigenetic processes. We used a two-step Mendelian randomization approach to assess whether DNA methylation plays a mediating and causal role in associations between maternal vitamin B₁₂ status and offspring’s cognition. Firstly, we estimated the causal effect of maternal vitamin B₁₂ levels on cord blood DNA methylation using the maternal FUT2 genotypes rs492602:A > G and rs1047781:A > T as proxies for circulating vitamin B₁₂ levels in the Avon Longitudinal Study of Parents and Children (ALSPAC) and we tested the observed associations in a replication cohort. Secondly, we estimated the causal effect of DNA methylation on IQ using the offspring genotype at sites close to the methylated CpG site as a proxy for DNA methylation in ALSPAC and in a replication sample. The first step Mendelian randomization estimated that maternal vitamin B₁₂ had a small causal effect on DNA methylation in offspring at three CpG sites, which was replicated for one of the sites. The second step Mendelian randomization found weak evidence of a causal effect of DNA methylation at two of these sites on childhood performance IQ which was replicated for one of the sites. The findings support a causal effect of maternal vitamin B₁₂ levels on cord blood DNA methylation, and a causal effect of vitamin B₁₂-responsive DNA methylation changes on children’s cognition. Some limitations were identified and future studies using a similar approach should aim to overcome such issues.

Meat Consumption During Pregnancy and Substance Misuse Among Adolescent Offspring: Stratification of TCN2 Genetic Variants

BACKGROUND

Reducing meat consumption is often advised; however, inadvertent nutritional deficiencies during pregnancy may result in residual neurodevelopmental harms to offspring. This study assessed possible effects of maternal diets in pregnancy on adverse substance use among adolescent offspring.

METHODS

Pregnant women and their 13-year-old offspring taking part in a prospective birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC), provided Food Frequency Questionnaire data from which dietary patterns were derived using principal components analysis. Multivariable logistic regression models including potential confounders evaluated adverse alcohol, cannabis, and tobacco use of the children at 15 years of age.

RESULTS

Lower maternal meat consumption was associated with greater problematic substance use among 15-year-old offspring in dose-response patterns. Comparing never to daily meat consumption after adjustment, risks were greater for all categories of problem substance use: alcohol, odds ratio OR = 1.75, 95% CI = (1.23, 2.56), p < 0.001; tobacco use OR = 1.85, 95% CI = (1.28, 2.63), p < 0.001; and cannabis OR = 2.70, 95% CI = (1.89, 4.00), p < 0.001. Given the likelihood of residual confounding, potential causality was evaluated using stratification for maternal allelic variants that impact biological activity of cobalamin (vitamin B12) and iron. Lower meat consumption disproportionally increased the risks of offspring substance misuse among mothers with optimally functional (homozygous) variants (rs1801198) of the gene transcobalamin 2 gene (TCN2) which encodes the vitamin B12 transport protein transcobalamin 2 implicating a causal role for cobalamin deficits. Functional maternal variants in iron metabolism were unrelated to the adverse substance use. Risks potentially attributable to cobalamin deficits during pregnancy include adverse adolescent alcohol, cannabis, and tobacco use (14, 37, and 23, respectively).

CONCLUSIONS

Lower prenatal meat consumption was associated with increased risks of adolescent substance misuse. Interactions between TCN2 variant status and meat intake implicate cobalamin deficiencies.

Effect of maternal high dosages of folic acid supplements on neurocognitive development in children at 4-5 y of age: the prospective birth cohort Infancia y Medio Ambiente (INMA) study

Background: The benefits of the use of folic acid supplements (FASs) during the periconception period to prevent neural tube defects and to ensure normal brain development in offspring are well known. There is concern, however, about the long-term effects of the maternal use of high dosages of FASs that exceed the Tolerable Upper Intake Level (UL) (≥1000 μg/d) on child neurocognitive outcomes.Objective: The objective of the study was to examine the association between the use of high dosages of FASs during pregnancy and child neuropsychological development at ages 4-5 y.Design: The multicenter prospective mother-child cohort study, the Infancia y Medio Ambiente (INMA) Project, was conducted in 4 regions of Spain: Asturias, Sabadell, Gipuzkoa, and Valencia. Pregnant women were recruited between 2003 and 2008. Data on 1682 mother-child pairs were included in the final analyses. The pregnant women completed an interviewer-administered questionnaire that was validated to estimate typical dietary folate intake and the use of FASs at 10-13 and 28-32 wk of gestation. Neuropsychological development scores at 4-5 y of age were estimated with the use of the McCarthy Scales of Children's Abilities. Multiple linear regression and meta-analysis were used to obtain combined-effect estimates.Results: During the periconception period, one-third of the women (n = 502) took FAS dosages ≥1000 μg/d. The use of FAS dosages ≥1000 μg/d in this period was negatively associated with several neuropsychological outcomes scores in children: global verbal (β = -2.49; 95% CI: -4.71, -0.27), verbal memory (β = -3.59; 95% CI: -6.95, -0.23), cognitive function of posterior cortex (β = -2.31; 95% CI: -4.45, -0.18), and cognitive function of left posterior cortex (β = -3.26; 95% CI: -5.51, -1.01).Conclusions: The use of FAS dosages exceeding the UL (≥1000 μg/d) during the periconception period was associated with lower levels of cognitive development in children aged 4-5 y. The use of FAS dosages ≥1000 μg/d during pregnancy should be monitored and prevented as much as possible, unless medically prescribed.

Effect of B9 and B12 vitamin intake on semen parameters and fertility of men with MTHFR polymorphisms

The methylenetetrahydrofolate reductase (MTHFR) gene codes a crucial enzyme which involve in folate metabolism. The effect of MTHFR gene polymorphisms on male fertility status is uncertain and controversial. We evaluated the effect of B vitamin family intake on total homocysteine content and semen parameters of men with MTHFR gene polymorphisms. MTHFR genotypes frequency and serum total homocysteine concentration were measured among 280 men with impaired spermatogenesis (asthenospermia, oligospermia, severe oligospermia and azoospermia) and 85 control participants. B vitamin family dietary intakes were assessed using a semi-quantitative food-frequency questionnaire. In addition, concentrations of vitamins B9 and B12 were evaluated in serum samples of some participants (n = 60). We observed significantly higher frequency of TC or TT genotypes in C677T polymorphism among oligospermic, severe oligospermic and azoospermic men. CC genotype of A1298C polymorphism was significantly higher only in azoospermic men. Also, we observed critical effect of vitamin B9 and B12 intake on decreasing of total homocysteine and improving of semen parameters among the men with T allele of MTHFR C677T polymorphism. Our investigation showed that sufficient consumption of vitamins B9 and B12 influences sperm parameters of men with different MTHFR polymorphisms, especially genotypes with T allele.

New Perspective on Impact of Folic Acid Supplementation during Pregnancy on Neurodevelopment/Autism in the Offspring Children - A Systematic Review

It has been conclusively established that folic acid supplementation prior to and during early pregnancy (up to 12 weeks of gestation) can prevent neural tube defects (NTDs). We hypothesized that folate effects may extend from neuro-structural defects to alterations in neuro-behavioural and emotional skills including autism spectrum disorders (ASDs) and other developmental disorders. The objective of this review was to comprehensively evaluate evidence on the impact of folic acid on neurodevelopment other than NTDs. We conducted an online search of relevant literature compiled by the National Library of Medicine from Medline and EMBASE (searched on Dec 31, 2014: http://www.ncbi.nlm.nih.gov/entrez/query/fcgi and http://www.elsevier.com/online-tools/embase). We first created 3 files (search restricted to English literature) using the following key words: 1) folate or folic acid (171322 papers identified by this search); 2) maternal or pregnancy or pregnant or gestation or gestational or prenatal or antenatal or periconception or periconceptional (1349219 papers identified by this search); and 3) autism or autism spectrum disorders or developmental delay or development or neurodevelopment or mental or cognitive or language or personal-social or gross motor or fine motor or behaviour or intellectual or intelligence or Bayley Scale (8268145 papers identified by this search). We then merged the 3 files and reviewed the papers that addressed these three issues simultaneously. A total of 22 original papers that examined the association between folic acid supplementation in human pregnancy and neurodevelopment/autism were identified after the screening, with 15 studies showing a beneficial effect of folic acid supplementation on neurodevelopment/autism, 6 studies showed no statistically significant difference, while one study showed a harmful effect in > 5 mg folic acid supplementation/day during pregnancy. Folic acid supplementation in pregnancy may have beneficial effects on the neurodevelopment of children beyond its proven effect on NTDs.

Vitamin B-12 and Cognition in Children

Vitamin B-12 is essential for brain development, neural myelination, and cognitive function. Inadequate vitamin B-12 status during pregnancy and early childhood has been associated with adverse child health outcomes, including impaired cognitive development. However, the underlying mechanisms have not been elucidated. This review was conducted to examine the evidence that links vitamin B-12 and cognition in children. The search strategy resulted in 17 studies: 3 cross-sectional, 1 case-control, and 12 cohort studies, and 1 randomized trial. Cognitive processes assessed included attention, memory, and perception. Developmental outcomes, academic performance, and intelligence quotient were also considered. Despite the high prevalence of vitamin B-12 insufficiency and associated risk of adverse cognitive outcomes in children, to our knowledge, no studies to date have been conducted to examine the effects of vitamin B-12 supplementation on cognition in children. The role of vitamin B-12 in the etiology of child cognitive outcomes needs to be elucidated to inform public health interventions.

Association between maternal nutritional status in pregnancy and offspring cognitive function during childhood and adolescence; a systematic review

Background

The mother is the only source of nutrition for fetal growth including brain development. Maternal nutritional status (anthropometry, macro- and micro-nutrients) before and/or during pregnancy is therefore a potential predictor of offspring cognitive function. The relationship of maternal nutrition to offspring cognitive function is unclear. This review aims to assess existing evidence linking maternal nutritional status with offspring cognitive function.

Methods

Exposures considered were maternal BMI, height and weight, micronutrient status (vitamins D, B12, folate and iron) and macronutrient intakes (carbohydrate, protein and fat). The outcome was any measure of cognitive function in children aged <18 years. We considered observational studies and trials with allocation groups that differed by single nutrients. We searched Medline/PubMed and the Cochrane Library databases and reference lists of retrieved literature. Two reviewers independently extracted data from relevant articles. We used methods recommended by the Centre for Reviews and Dissemination, University of York and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

Of 16,143 articles identified, 38 met inclusion criteria. Most studies were observational, and from high-income settings. There were few randomized controlled trials. There was consistent evidence linking maternal obesity with lower cognitive function in children; low maternal BMI has been inadequately studied. Among three studies of maternal vitamin D status, two showed lower cognitive function in children of deficient mothers. One trial of folic acid supplementation showed no effects on the children’s cognitive function and evidence from 13 observational studies was mixed. Among seven studies of maternal vitamin B12 status, most showed no association, though two studies in highly deficient populations suggested a possible effect. Four out of six observational studies and two trials (including one in an Iron deficient population) found no association of maternal iron status with offspring cognitive function. One trial of maternal carbohydrate/protein supplementation showed no effects on offspring cognitive function.

Conclusions

Current evidence that maternal nutritional status during pregnancy as defined by BMI, single micronutrient studies, or macronutrient intakes influences offspring cognitive function is inconclusive. There is a need for more trials especially in populations with high rates of maternal undernutrition.

Systematic review registration

Registered in PROSPERO CRD42013005702.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1011-z) contains supplementary material, which is available to authorized users.

Effects of maternal vitamin B12 supplementation on early infant neurocognitive outcomes: a randomized controlled clinical trial

Maternal nutritional status during pregnancy impacts fetal brain development. Vitamin B12 plays a vital role in neuronal development. However, findings from studies on the association between maternal B12 status and child cognitive functions have been inconsistent. We performed a randomized, placebo-controlled clinical trial of oral B12 supplementation (50 µg) beginning at <14 weeks of gestation through a 6-week post-partum. In the present study, we report the effects of maternal B12 supplementation on cognitive development in infants at 9 months of age on Bayley Scales of Infant Development-III (BSID-III). One hundred eighty-three pregnant women received vitamin B12, and 183 received placebo. Nine-month BSID-III development score was available in 178 infants. There were no significant differences in maternal sociodemographic characteristics and baseline biochemical measures between infants who underwent BSID-III evaluation and infants who were not evaluated. There were no significant differences in any of the subscales of BSID-III between infants born to mothers who received B12 supplementation (n = 78) vs. placebo (n = 100). On multiple regression analysis, elevated maternal total homocysteine (tHcy) levels adjusted for treatment group, birthweight, parity, income and home environment at second trimester of pregnancy were significantly negatively associated with expressive language (β = 3.13 points, P < 0.001), and in third trimester of pregnancy with expressive language (β = -2.29 points, P < 0.001) and fine motor (β = -1.41 points, P = 0.005) domains of BSID-III. While no significant effects of maternal B12 supplementation were seen on cognitive development in infants at 9 months of age, elevated maternal tHcy levels were associated with poorer cognitive performance in some of the subdomains of BSID-III. In pregnant women with elevated tHcy levels and or B12 deficiencies, it may be worthwhile to study the impact of longer term maternal supplementation on infant cognitive outcomes.

The interplay between DNA methylation, folate and neurocognitive development

DNA methylation provides an attractive possible means for propagating the effects of environmental inputs during fetal life and impacting subsequent adult mental health, which is leading to increasing collaboration between molecular biologists, nutritionists and psychiatrists. An area of interest is the potential role of folate, not just in neural tube closure in early pregnancy, but in later major neurodevelopmental events, with consequences for later sociocognitive maturation. Here, we set the scene for recent discoveries by reviewing the major events of neural development during fetal life, with an emphasis on tissues and structures where dynamic methylation changes are known to occur. Following this, we give an indication of some of the major classes of genes targeted by methylation and important for neurological and behavioral development. Finally, we highlight some cognitive disorders where methylation changes are implicated as playing an important role.

Contributions of a Child's Built, Natural, and Social Environments to Their General Cognitive Ability: A Systematic Scoping Review

The etiology of a child’s cognitive ability is complex, with research suggesting that it is not attributed to a single determinant or even a defined period of exposure. Rather, cognitive development is the product of cumulative interactions with the environment, both negative and positive, over the life course. The aim of this systematic scoping review was to collate evidence associated with children’s cognitive health, including inherent factors as well as chemical and non-chemical stressors from the built, natural, and social environments. Three databases were used to identify recent epidemiological studies (2003–2013) that examined exposure factors associated with general cognitive ability in children. Over 100 factors were evaluated from 258 eligible studies. We found that recent literature mainly assessed the hypothesized negative effects of either inherent factors or chemical exposures present in the physical environment. Prenatal growth, sleep health, lead and water pollutants showed consistent negative effects. Of the few studies that examined social stressors, results consistently showed cognitive development to be influenced by both positive and negative social interactions at home, in school or the community. Among behavioral factors related to diet and lifestyle choices of the mother, breastfeeding was the most studied, showing consistent positive associations with cognitive ability. There were mostly inconsistent results for both chemical and non-chemical stressors. The majority of studies utilized traditional exposure assessments, evaluating chemical and non-chemical stressors separately. Collective evidence from a limited number of studies revealed that cumulative exposure assessment that incorporates multiple chemical and non-chemical stressors over the life course may unravel the variability in effect on cognitive development and help explain the inconsistencies across studies. Future research examining the interactions of multiple stressors within a child’s total environment, depicting a more real-world exposure, will aid in understanding the cumulative effects associated with a child’s ability to learn.

Moderately elevated maternal homocysteine at preconception is inversely associated with cognitive performance in children 4 months and 6 years after birth

Prenatal methyl donor deficiency leads to homocysteine accumulation in the brain and impaired neurodevelopment in rats. We investigated the effect of moderately elevated preconception fasting total plasma homocysteine (tHcy) on child neurodevelopment in a prospective study of 67 and 76 mother-child pairs at 4 months and 6 years of age, respectively. Fasting blood samples at 2-10 weeks preconception, from the cord (nonfasting) and the mother and child 6 years after birth, were collected. Psychomotor and mental development were assessed at 4 months using the Bayley Scale of Infant Development (BSID) and cognitive development at 6 years using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI). Highest tertile preconception tHcy (≥9.04 µmol/L) was categorized as moderately elevated and low-mid tertile tHcy as normal. Children, born to mothers with moderately elevated compared to normal preconception tHcy, scored lower [mean (95% CI)] in the BSID psychomotor [115 (105, 124) vs. 126 (121, 130), p = 0.03] and mental [101 (93, 109) vs. 113 (107, 119), p = 0.03] development tests. Multiple logistic regression analysis showed that moderately elevated compared to normal preconception tHcy was associated with greater probability, OR (95%CI), of scoring in the lowest tertile for BSID psychomotor development (≤120): 4.0 (1.1, 14.3) and lowest tertiles for WPPSI full (≤111), verbal (≤104) and performance (≤111), intellectual quotient: 6.0 (1.5, 23.7), 3.5 (1.1, 11.2) and 4.1 (1.1, 15.7), respectively. We conclude that moderately elevated preconception tHcy is inversely associated with psychomotor and cognitive development scores in infants and children.

Prenatal folate, homocysteine and vitamin B12 levels and child brain volumes, cognitive development and psychological functioning: the Generation R Study

Previous studies have suggested that prenatal maternal folate deficiency is associated with reduced prenatal brain growth and psychological problems in offspring. However, little is known about the longer-term impact. The aims of this study were to investigate whether prenatal maternal folate insufficiency, high total homocysteine levels and low vitamin B12 levels are associated with altered brain morphology, cognitive and/or psychological problems in school-aged children. This study was embedded in Generation R, a prospective population-based cohort study. The study sample consisted of 256 Dutch children aged between 6 and 8 years from whom structural brain scans were collected using MRI. The mothers of sixty-two children had insufficient (<8 nmol/l) plasma folate concentrations in early pregnancy. Cognitive development was assessed by the Snijders-Oomen Niet-verbale intelligentietest - Revisie and the NEPSY-II-NL. Psychological problems were assessed at age 6 years using the parent report of the Child Behavior Checklist. Low prenatal folate levels were associated with a smaller total brain volume (B -33·34; 95 % CI -66·7, 0·02; P=050) and predicted poorer performance on the language (B -0·28; 95 % CI -0·52, -0·04; P=0·020) and visuo-spatial domains (B -0·27; 95 % CI -0·50, -0·04; P=0·021). High homocysteine levels (>9·1 µmol/l) predicted poorer performance on the language (B -0·31; 95 % CI -0·56, -0·06; P=0·014) and visuo-spatial domains (B -0·36; 95 % CI -0·60, -0·11; P=0·004). No associations with psychological problems were found. Our findings suggest that folate insufficiency in early pregnancy has a long-lasting, global effect on brain development and is, together with homocysteine levels, associated with poorer cognitive performance.

Vitamin B-12 and Perinatal Health

Vitamin B-12 deficiency (<148 pmol/L) is associated with adverse maternal and neonatal outcomes, including developmental anomalies, spontaneous abortions, preeclampsia, and low birth weight (<2500 g). The importance of adequate vitamin B-12 status periconceptionally and during pregnancy cannot be overemphasized, given its fundamental role in neural myelination, brain development, and growth. Infants born to vitamin B-12-deficient women may be at increased risk of neural tube closure defects, and maternal vitamin B-12 insufficiency (<200 pmol/L) can impair infant growth, psychomotor function, and brain development, which may be irreversible. However, the underlying causal mechanisms are unknown. This review was conducted to examine the evidence that links maternal vitamin B-12 status and perinatal outcomes. Despite the high prevalence of vitamin B-12 deficiency and associated risk of pregnancy complications, few prospective studies and, to our knowledge, only 1 randomized trial have examined the effects of vitamin B-12 supplementation during pregnancy. The role of vitamin B-12 in the etiology of adverse perinatal outcomes needs to be elucidated to inform public health interventions.

Vitamin B-12 Deficiency in Children Is Associated with Grade Repetition and School Absenteeism, Independent of Folate, Iron, Zinc, or Vitamin A Status Biomarkers

BACKGROUND

Micronutrients are essential to neurocognitive development; yet their role in educational outcomes is unclear.

OBJECTIVE

We examined the associations of micronutrient status biomarkers with the risk of grade repetition and rates of school absenteeism in a cohort of school children.

METHODS

We recruited 3156 children aged 5-12 y from public schools in Bogota, Colombia. Circulating ferritin, hemoglobin, zinc, vitamin A, and vitamin B-12; erythrocyte folate; and mean corpuscular volume (MCV) were measured in blood samples obtained at the beginning of the year. Absenteeism was recorded weekly during the school year, and grade repetition was determined the next year. Risk ratios for grade repetition and rate ratios for absenteeism were estimated by categories of micronutrient status indicators with use of Poisson regression, adjusting for potential confounders.

RESULTS

The risk of grade repetition was 4.9%, and the absenteeism rate was 3.8 d per child-year of observation. Vitamin B-12 deficiency (<148 pmol/L) was associated with an adjusted 2.36-fold greater risk of grade repetition (95% CI: 1.03, 5.41; P = 0.04) compared with plasma concentrations ≥148 pmol/L. Other micronutrients were not related to grade repetition. Vitamin B-12 deficiency was also associated with school absenteeism rates. Compared with children with plasma vitamin B-12 concentrations ≥148 pmol/L, vitamin B-12-deficient children had a 1.89-times higher adjusted rate (95% CI: 1.53, 2.34; P < 0.0001). Anemia was related to a 72% higher rate (95% CI: 48%, 99%; P < 0.0001), whereas every 5-fL difference in MCV was associated with a 7% lower adjusted rate (95% CI: 4%, 10%; P < 0.0001).

CONCLUSIONS

Vitamin B-12 deficiency was associated with risk of grade repetition and school absenteeism rates in school children from Bogota, Colombia. The effects of correcting vitamin B-12 deficiency on educational outcomes and neurocognitive development of school children need to be determined in intervention studies.

MTHFR deficiency or reduced intake of folate or choline in pregnant mice results in impaired short-term memory and increased apoptosis in the hippocampus of wild-type offspring

Genetic or nutritional disturbances in one-carbon metabolism, with associated hyperhomocysteinemia, can result in complex disorders including pregnancy complications and neuropsychiatric diseases. In earlier work, we showed that mice with a complete deficiency of methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate and homocysteine metabolism, had cognitive impairment with disturbances in choline metabolism. Maternal demands for folate and choline are increased during pregnancy and deficiencies of these nutrients result in several negative outcomes including increased resorption and delayed development. The goal of this study was to investigate the behavioral and neurobiological impact of a maternal genetic deficiency in MTHFR or maternal nutritional deficiency of folate or choline during pregnancy on 3-week-old Mthfr(+/+) offspring. Mthfr(+/+) and Mthfr(+/-) females were placed on control diets (CD); and Mthfr(+/+) females were placed on folate-deficient diets (FD) or choline-deficient diets (ChDD) throughout pregnancy and lactation until their offspring were 3weeks of age. Short-term memory was assessed in offspring, and hippocampal tissue was evaluated for morphological changes, apoptosis, proliferation and choline metabolism. Maternal MTHFR deficiency resulted in short-term memory impairment in offspring. These dams had elevated levels of plasma homocysteine when compared with wild-type dams. There were no differences in plasma homocysteine in offspring. Increased apoptosis and proliferation was observed in the hippocampus of offspring from Mthfr(+/-) mothers. In the maternal FD and ChDD study, offspring also showed short-term memory impairment with increased apoptosis in the hippocampus; increased neurogenesis was observed in ChDD offspring. Choline acetyltransferase protein was increased in the offspring hippocampus of both dietary groups and betaine was decreased in the hippocampus of FD offspring. Our results reveal short-term memory deficits in the offspring of dams with MTHFR deficiency or dietary deficiencies of critical methyl donors. We suggest that deficiencies in maternal one-carbon metabolism during pregnancy can contribute to hippocampal dysfunction in offspring through apoptosis or altered choline metabolism.

A potential interaction between COMT and MTHFR genetic variants in Han Chinese patients with bipolar II disorder

Bipolar II disorder (BP-II), characterized by recurrent dysregulation of mood, is a serious and chronic psychiatric illness. However, BP-II is commonly under-recognized, even in psychiatric settings. Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenetetrahydrofolate reductase (MTHFR) gene, which may affect COMT methylation and COMT function. The current study examined the association and interaction of the COMT Val158Met and MTHFR C677T variants with BP-II. Nine hundred seventy-eight participants were recruited: 531 with BP-II and 447 healthy controls. The genotypes of the COMT and MTHFR polymorphisms were determined using a polymerase chain reaction-restriction fragment length polymorphism analysis. Logistic regression analysis showed a significant interaction effect of the COMT Val158Met Val/Val genotype and the MTHFR C677T C/T + T/T genotype (P = 0.039) for the protective effect on the odds of developing BP-II. Our findings support preliminary evidence that the COMT and MTHFR genes interact in BP-II, and they imply the connection of both dopaminergic pathways and methylation pathways in the pathogenesis of BP-II.

Emerging roles for folate and related B-vitamins in brain health across the lifecycle

Nutrition plays a fundamental role in supporting the structural and functional development of the human brain from conception, throughout early infancy and extending into later life. A growing body of evidence suggests that folate and the metabolically related B-vitamins are essential for brain health across all age groups, owing to their specific roles in C1 metabolism and particularly in the production of S-adenosylmethionine, a universal methyl donor essential for the production of neurotransmitters. Emerging, though not entirely consistent, evidence suggests that maternal folate status throughout pregnancy may influence neurodevelopment and behaviour of the offspring. Furthermore optimal B-vitamin status is associated with better cognitive health in ageing. Of note, a recent clinical trial provided evidence that supplementation with folic acid and related B-vitamins over a 2-year-period reduced global and regional brain atrophy, as measured by MRI scan in older adults. In terms of potential mechanisms, the effects of these B-vitamins on cognitive health may be independent or may be mediated by nutrient-nutrient and/or relevant gene-nutrient interactions. Furthermore, a new area of research suggests that the in utero environment influences health in later life. Folate, an important cofactor in C1 metabolism, is indirectly involved in DNA methylation, which in turn is considered to be one of the epigenetic mechanisms that may underlie fetal programming and brain development. The present review will explore the evidence that supports a role for folate and the related B-vitamins in brain health across the lifecycle, and potential mechanisms to explain such effects.

Maternal dietary intake of folate, vitamin B12 and MTHFR 677C>T genotype: their impact on newborn's anthropometric parameters

In this study, we evaluated the effects of dietary intake of vitamin B12 and folate during pregnancy and their interactions with maternal polymorphism of MTHFR (677C>T; 1298A>C) on intrauterine development. Anthropometric parameters were obtained from 231 newborns that belong to a prospective birth cohort in Morelos, Mexico. Maternal dietary intake of vitamin B12 and folate was assessed using a semi-quantitative questionnaire administered during the first and third trimesters of the pregnancy. Maternal MTHFR 677C>T and 1298 A>C genotypes were determined by PCR-RFLP. The associations between deficient dietary intake of vitamin B12 (<2.0 μg/d) and folate (<400 μg/d) in the first and third trimesters and maternal polymorphisms of MTHFR on anthropometric parameters at birth were estimated using a multivariate linear regression model. During pregnancy, the deficient dietary intake was roughly 60 % for folate and 19 % for vitamin B12. Allelic frequencies of 677T and 1298C were 59 and 10 %, respectively. After adjusting for confounders, deficiency in maternal dietary intake of vitamin B12 (<2.0 μg/d) was associated with a significant reduction in length (β ~ -2.4; 95 % CI -4.3; -0.6) and length-for-age at birth (β ~ -1.2; 95 % CI -2.3; -0.1) among infants whose mothers were carriers of the 677TT genotype (p for interaction = 0.02). In contrast, no association was observed between deficiency in maternal dietary intake of folate (<400 μg/d) and any anthropometric parameter of newborns. These results suggest that supplementation with vitamin B12 during pregnancy could have a favorable impact on intrauterine fetal development mainly in populations that are genetically susceptible.

B vitamin polymorphisms and behavior: evidence of associations with neurodevelopment, depression, schizophrenia, bipolar disorder and cognitive decline

The B vitamins folic acid, vitamin B12 and B6 are essential for neuronal function, and severe deficiencies have been linked to increased risk of neurodevelopmental disorders, psychiatric disease and dementia. Polymorphisms of genes involved in B vitamin absorption, metabolism and function, such as methylene tetrahydrofolate reductase (MTHFR), cystathionine β synthase (CβS), transcobalamin 2 receptor (TCN2) and methionine synthase reductase (MTRR), have also been linked to increased incidence of psychiatric and cognitive disorders. However, the effects of these polymorphisms are often quite small and many studies failed to show any meaningful or consistent associations. This review discusses previous findings from clinical studies and highlights gaps in knowledge. Future studies assessing B vitamin-associated polymorphisms must take into account not just traditional demographics, but subjects' overall diet, relevant biomarkers of nutritional status and also analyze related genetic factors that may exacerbate behavioral effects or nutritional status.

Methylenetetrahydrofolate reductase (MTHFR) polymorphism susceptibility to schizophrenia and bipolar disorder: an updated meta-analysis

Previous studies examining the possible role of the methylenetetrahydrofolate reductase (MTHFR) polymorphisms in the development of schizophrenia (SZ) and bipolar disorder (BPD) have provided inconclusive findings, this meta-analysis was therefore designed to get a more reliable assessment. A total of 38 articles were identified through a search of electronic databases, up to 27 February 2014. Odds ratios (ORs) with 95% confidence interval (CIs) were calculated using random effects models. Meta-analysis showed that MTHFR C677T was significantly associated with SZ, the highest OR was found for the recessive model (for TT vs. CT + CC: OR = 1.34, 95% CI: 1.18-1.53); a marginal association of MTHFR C677T with increased risk of BPD has also been found for the recessive model (OR = 1.26, 95% CI: 1.00-1.59). Subgroup analysis by ethnicity indicated that the significant association with SZ and BPD existed among Asian and African populations, but not for the white. MTHFR A1298C was significant associated with SZ, the highest OR for the dominant model (OR = 1.13, 95% CI: 1.03-1.24). Subgroup analysis indicated a significant association with SZ existed in Asian populations, not among the white populations and no significant association was detected between the MTHFR A1298C and BPD in all groups. We conclude that MTHFR polymorphism is associated with SZ and BPD among Asian, African populations, but not the white.

Choline intake during pregnancy and child cognition at age 7 years

Animal models indicate that exposure to choline in utero improves visual memory through cholinergic transmission and/or epigenetic mechanisms. Among 895 mothers in Project Viva (eastern Massachusetts, 1999-2002 to 2008-2011), we estimated the associations between intakes of choline, vitamin B12, betaine, and folate during the first and second trimesters of pregnancy and offspring visual memory (measured by the Wide Range Assessment of Memory and Learning, Second Edition (WRAML2), Design and Picture Memory subtests) and intelligence (measured using the Kaufman Brief Intelligence Test, Second Edition (KBIT-2)) at age 7 years. Mean second-trimester intakes were 328 (standard deviation (SD), 63) mg/day for choline, 10.5 (SD, 5.1) µg/day for vitamin B12, 240 (SD, 104) mg/day for betaine, and 1,268 (SD, 381) µg/day for folate. Mean age 7 test scores were 17.2 (SD, 4.4) points on the WRAML 2 Design and Picture Memory subtests, 114.3 (SD, 13.9) points on the verbal KBIT-2, and 107.8 (SD, 16.5) points on the nonverbal KBIT-2. In a model adjusting for maternal characteristics, the other nutrients, and child's age and sex, the top quartile of second-trimester choline intake was associated with a child WRAML2 score 1.4 points higher (95% confidence interval: 0.5, 2.4) than the bottom quartile (P-trend = 0.003). Results for first-trimester intake were in the same direction but weaker. Intake of the other nutrients was not associated with the cognitive tests administered. Higher gestational choline intake was associated with modestly better child visual memory at age 7 years.

Vitamin B-12 status during pregnancy and child's IQ at age 8: a Mendelian randomization study in the Avon longitudinal study of parents and children

Vitamin B-12 is essential for the development and maintenance of a healthy nervous system. Brain development occurs primarily in utero and early infancy, but the role of maternal vitamin B-12 status during pregnancy on offspring cognitive function is unclear. In this study we assessed the effect of vitamin B-12 status in well-nourished pregnant women on the cognitive ability of their offspring in a UK birth cohort (ALSPAC). We then examined the association of SNPs in maternal genes FUT2 (rs492602) and TCN2 (rs1801198, rs9606756) that are related to plasma vitamin B-12, with offspring IQ. Observationally, there was a positive association between maternal vitamin B-12 intake and child’s IQ that was markedly attenuated after adjustment for potential confounders (mean difference in offspring IQ score per doubling of maternal B-12 intake, before adjustment: 2.0 (95% CI 1.3, 2.8); after adjustment: 0.7 (95% CI −0.04, 1.4)). Maternal FUT2 was weakly associated with offspring IQ: mean difference in IQ per allele was 0.9 (95% CI 0.1, 1.6). The expected effect of maternal vitamin B-12 on offspring IQ, given the relationships between SNPs and vitamin B-12, and SNPs and IQ was consistent with the observational result. Our findings suggest that maternal vitamin B-12 may not have an important effect on offspring cognitive ability. However, further examination of this issue is warranted.

Maternal intake of methyl-donor nutrients and child cognition at 3 years of age

Methyl-donor nutrients are substrates for methylation reactions involved in neurodevelopment processes. The role of maternal intake of these nutrients on cognitive performance of the offspring is poorly understood. We examined the associations of maternal intake of folate, vitamin B12, choline, betaine and methionine during the first and second trimesters of pregnancy, with tests of cognitive performance in the offspring at 3 years of age using data from 1210 participants in Project Viva, a prospective pre-birth cohort study in Massachusetts. We assessed nutrient intake with the use of food frequency questionnaires. Children's cognition at age 3 years was evaluated with the Peabody Picture Vocabulary Test III (PPVT-III) and visual-motor skills with the Wide Range Assessment of Visual Motor Abilities test. In multivariable models adjusting for potential sociobehavioural and nutritional confounders, for each 600 µg/day increment in total folate intake during the first trimester, PPVT-III score at age 3 years was 1.6 points [95% confidence interval (CI) 0.1, 3.1; P = 0.04] higher. There was a weak inverse association between vitamin B12 intake during the second trimester and PPVT-III scores [-0.4 points per 2.6 µg/day; 95% CI -0.8, -0.1; P = 0.01]. We did not find associations between choline, betaine or methionine and cognitive outcomes at this age. Results of this study suggest that higher intake of folate in early pregnancy is associated with higher scores on the PPVT-III, a test of receptive language that predicts overall intelligence, at age 3 years.