This study aimed to explore the mediation effects of one-carbon metabolism (OCM) related nutrients on the association between MTHFR rs1801133 polymorphism and gestational diabetes mellitus (GDM). Folate, vitamin B12 and homocysteine (Hcy) were measured in the serum of 1254 pregnant women. Linear and logistic regressions were used to estimate the associations of OCM nutrients and MTHFR rs1801133 polymorphism with blood glucose levels and GDM risk. Mediation analysis was applied to test the mediation effects of folate, vitamin B12 and Hcy on the association of MTHFR rs1801133 polymorphism with blood glucose concentrations and GDM. Pregnant women with MTHFR rs1801133 CC genotype had higher serum folate (10·75 v. 8·90 and 9·40 ng/ml) and lower serum Hcy (4·84 v. 4·93 and 5·20 μmol/l) than those with CT and TT genotypes. Folate concentrations were positively associated with fasting plasma glucose (FPG), 1-h plasma glucose (1-h PG), 2-h plasma glucose (2-h PG) and GDM risk. Vitamin B12 levels were negatively correlated with FPG and GDM. Although no direct association was found between MTHFR rs1801133 genotypes and GDM, there were significant indirect effects of MTHFR rs1801133 CC genotype on FPG (β: 0·005; 95 % CI: 0·001, 0·013), 1-h PG (β: 0·006; 95 % CI: 0·001, 0·014), 2-h PG (β: 0·007; 95 % CI: 0·001, 0·015) and GDM (β: 0·006; 95 % CI: 0·001, 0·014) via folate. In conclusion, serum folate mediates the effect of MTHFR rs1801133 on blood glucose levels and GDM. Our findings potentially provide a feasible GDM prevention strategy via individualised folate supplementation according to the MTHFR genotypes.

Folate and vitamin B12 are essential for growth. Our objective was to estimate their long-term effects on linear growth in North Indian children. This is a follow-up study of a factorial designed, double-blind, randomised, placebo-controlled trial in 1000 young children. Starting at 6–30 months of age, we gave folic acid (approximately 2 RDA), vitamin B12 (approximately 2 RDA), both vitamins or a placebo daily for 6 months. Six years after the end of supplementation, we measured height in 791 children. We used the plasma concentrations of cobalamin, folate and total homocysteine to estimate vitamin status. The effect of the interventions, the association between height-for-age z-scores (HAZ) and baseline vitamin status, and the interactions between supplementation and baseline status were estimated in multiple regression models. Mean (sd) age at follow-up was 7·4 (0·7) years (range 6 to 9 years). There was a small, non-significant effect of vitamin B12 on linear growth and no effect of folic acid. We observed a subgroup effect of vitamin B12 supplementation in those with plasma cobalamin concentration < 200 pmol/l (P for interaction = 0·01). The effect of vitamin B12 supplementation in this group was 0·34 HAZ (95 % CI 0·11, 0·58). We found an association between cobalamin status and HAZ in children not given vitamin B12 (P for interaction = 0·001). In this group, each doubling of the cobalamin concentration was associated with 0·26 (95 % CI 0·15, 0·38) higher HAZ. Suboptimal vitamin B12 status in early childhood seemingly limits linear growth in North Indian children.

Immunoprophylaxis has not completely eliminated hepatitis B virus (HBV) infection due to hyporesponsiveness to hepatitis B vaccine (HepB). We explored the impact of folic acid supplementation (FAS) in pregnant women with positive hepatitis B surface antigen (HBsAg) on their infant hepatitis B surface antibody (anti-HBs) and the mediation effect of infant interleukin-4 (IL-4). We recruited HBsAg-positive mothers and their neonates at baseline. Maternal FAS was obtained via a questionnaire, and neonatal anti-HBs and IL-4 were detected. Follow-up was performed at 11–13 months of age of infants, when anti-HBs and IL-4 were measured. We applied univariate and multivariate analyses. A mediation effect model was performed to explore the mediating role of IL-4. A total of 399 mother–neonate pairs were enrolled and 195 mother–infant pairs were eligible for this analysis. The infant anti-HBs geometric mean concentrations in the maternal FAS group were significnatly higher than those in the no-FAS group (383·8 mIU/ml, 95 % CI: 294·2 mIU/ml to 500·7 mIU/ml v. 217·0 mIU/ml, 95 % CI: 147·0 mIU/ml to 320·4 mIU/ml, z = –3·2, P = 0·001). Infants born to women who took folic acid (FA) within the first trimester were more likely to have high anti-HBs titres (adjusted β-value = 194·1, P = 0·003). The fold change in IL-4 from neonates to infants partially mediated the beneficial influence of maternal FAS on infant anti-HBs (24·7 % mediation effect) after adjusting for confounding factors. FAS during the first trimester to HBsAg-positive mothers could facilitate higher anti-HBs levels in infants aged 11–13 months partly by upregulating IL-4 in infants.

Periconceptional folic acid supplementation is effective in the prevention of neural tube defects (NTDs). The aim of the present study was to determine the level of knowledge about the benefits of preconceptional folic acid supplementation in a sample of women of childbearing age and its associated factors. A cross-sectional community-based study design was carried out on a total of 441 women of childbearing age. Questionnaires included knowledge of preconception of folic acid supplements and socio-demographic characteristics. The χ2 was used to compare categorical data. Multivariate logistic regression was used to isolate the predictive variables and examined individually by calculating the adjusted odds ratio. Statistical significance is declared as P < 0·05. We found that 35·1 % (n 155) knew preconceptional folic acid supplementation could prevent NTDs, and 3·8 % (n 17) knew the right time to take preconceptional folic acid supplementation and only 1·7 % (n 7) who had a history of NTDs. Attended secondary education (OR 2·7; 95 % CI 1·1, 6·0, P = 0·017), governmental employee (OR 3·5; 95 % CI 2·3, 17·8, P < 0·001), current pregnancy status (OR 3·0; 95 % CI 2·1, 4·2, P = 0·043), history of visiting the antenatal care service during pregnancy (OR 2·9; 95 % CI 1·07, 7·8, P = 0·03), history of taking folic acid supplement (OR 4·5; 95 % CI 2·9, 7·1, P < 0·001) were associated. More than half of the participant women did not know about preconception of folic acid supplements that reduce the risk of NTDs. Identification of the level of knowledge on preconception of folic acid may allow for targeted educational or other interventions to further encourage folic acid use.

This study examined the influences of coated folic acid (CFA) and coated riboflavin (CRF) on bull performance, nutrients digestion and ruminal fermentation. Forty-eight Angus bulls based on a randomised block and 2 × 2 factorial design were assigned to four treatments. The CFA of 0 or 6 mg of folic acid/kg DM was supplemented in diets with CRF 0 or 60 mg riboflavin (RF)/kg DM. Supplementation of CRF in diets with CFA had greater increase in daily weight gain and feed efficiency than in diets without CFA. Supplementation with CFA or CRF enhanced digestibility of DM, organic matter, crude protein, neutral-detergent fibre and non-fibre carbohydrate. Ruminal pH and ammonia N content decreased and total volatile fatty acids concentration and acetate to propionate ratio elevated for CFA or CRF addition. Supplement of CFA or CRF increased the activities of fibrolytic enzymes and the numbers of total bacteria, protozoa, fungi, dominant fibrolytic bacteria and Prevotella ruminicola. The activities of α-amylase, protease and pectinase and the numbers of Butyrivibrio fibrisolvens and Ruminobacter amylophilus were increased by CFA but were unaffected by CRF. Blood concentration of folate elevated and homocysteine decreased for CFA addition. The CRF supplementation elevated blood concentrations of folate and RF. These findings suggested that CFA or CRF inclusion had facilitating effects on performance and ruminal fermentation, and combined addition of CFA and CRF had greater increase in performance than CFA or CRF addition alone in bulls.

We evaluated the association between maternal prenatal folic acid supplementation/dietary folate intake and motor and cognitive development in 2-year-old offspring using data from the Japan Environment and Children’s Study database. Neurodevelopment of 2-year-old offspring were evaluated using the Kyoto Scale of Psychological Development 2001. In total, data of 3839 offspring were analysed. For folic acid supplementation, a multiple regression analysis showed that offspring of mothers who started using folic acid supplements before conception had a significantly lower developmental quotient (DQ) in the postural-motor DQ area than offspring of mothers who did not use them at any time throughout their pregnancy (partial regression coefficient (B) −2·596, 95 % CI −4·738, −0·455). Regarding daily dietary folate intake from preconception to early pregnancy, a multiple regression analysis showed that the group with ≥ 200 µg had a significantly higher DQ in the language-social area than the group with <200 µg. The DQ was higher in the ≥ 400 µg group (B 2·532, 95 % CI 0·201, 4·863) than the 200 to <400 µg group (B 1·437, 95 % CI 0·215, 2·660). In conclusion, our study showed that maternal adequate dietary folate intake from preconception to early pregnancy has a beneficial association with verbal cognition development in 2-year-old offspring. On the other hand, mothers who started using folic acid supplements before conception had an inverse association with motor development in 2-year-old offspring. There were no details on the amount of folic acid in the supplements used and frequency of use. Therefore, further studies are required.

This research evaluates the prevalence of inadequate folate status in early pregnancy, the pattern of prenatal folic acid (FA) supplementation and associated factors in Spanish pregnant women from the ECLIPSES study, which included 791 participants prior gestational week 12. A cross-sectional evaluation of erythrocyte folate levels was performed at recruitment and used to calculate the prevalence of folate deficiency (erythrocyte folate < 340 nmol/l) and insufficiency (erythrocyte folate < 906 nmol/l). Sociodemographic and lifestyle data as well as information on prenatal FA supplementation were recorded. Descriptive and multivariate statistical analyses were performed. The prevalence of folate deficiency and insufficiency were 9·6 % and 86·5 %, respectively. Most of women used prenatal FA supplements, but only 6·3 % did so as recommended. Supplementation with FA during the periconceptional period abolished folate deficiency and reduced folate insufficiency. Prenatal FA supplementation with ≥1000 µg/d in periconceptional time and pregnancy planning increased erythrocyte folate levels. The main risk factor for folate insufficiency in early pregnancy was getting prenatal FA supplementation out of the periconceptional time (OR 3·32, 95 % CI 1·02, 15·36), while for folate deficiency they were young age (OR 2·02, 95 % CI 1·05, 3·99), and smoking (OR 2·39, 95 % CI 1·30, 4·37). In addition, social and ethnic differences according to folate status were also identified. As conclusion, periconceptional FA use is crucial for achieving optimal folate levels in early pregnancy. Pregnancy planning should focus on young women, smokers, those with low consumption of folate-rich foods, low socio-economic status or from ethnic minorities.

The aim of this study was to evaluate the association between prenatal and neonatal period exposures and the risk of childhood and adolescent nasopharyngeal carcinoma (NPC). From January 2009 to January 2016, a total of 46 patients with childhood and adolescent NPC (i.e., less than 18 years of age) who were treated at Sun Yat-sen University Cancer Center were screened as cases, and a total of 45 cancer-free patients who were treated at Sun Yat-sen University Zhongshan Ophthalmic Center were selected as controls. The association between maternal exposures during pregnancy and obstetric variables and the risk of childhood and adolescent NPC was evaluated using logistic regression analysis. Univariate analysis revealed that compared to children and adolescents without a family history of cancer, those with a family history of cancer had a significantly higher risk of childhood and adolescent NPC [odds ratios (OR) = 3.15, 95% confidence interval (CI) = 1.02–9.75, P = 0.046], and the maternal use of folic acid and/or multivitamins during pregnancy was associated with a reduced risk of childhood and adolescent NPC in the offspring (OR = 0.07, 95% CI = 0.02–0.25, P < 0.001). After multivariate analysis, only the maternal use of folic acid and/or multivitamins during pregnancy remained statistically significant. These findings suggest that maternal consumption of folic acid and/or multivitamins during pregnancy is associated with a decreased risk of childhood and adolescent NPC in the offspring.

The objectives were to compare the evolution of dietary folate intake, to estimate the prevalence of folate inadequacy (POFI) and the contribution of food groups to folate intake (dietary folate plus folic acid from fortified foods) in two post-fortification periods in the Brazilian population, according to life stages, geographic regions and per capita income. Population-based study including representative data from the National Dietary Survey – Brazilian Household Budget Surveys (NDS-HBS) 2008–2009 and 2017–2018, with a total of 32 749 (2008–2009) and 44 744 (2017–2018) individuals aged ≥ 10 years old, excluding pregnant and lactating women. The National Cancer Institute method was used to estimate the distributions of usual dietary folate intake. POFI was estimated according to estimated average requirement cut-off point method. After 10 years of the first NDS-HBS, POFI has increased in all sex-age groups, except for 10–13 years. POFI among women of reproductive age was around 30 and 40 % in 2008–2009 and 2017–2018. Higher POFI was observed in the North region. The top five food groups contributors to folate intake in Brazil were beans, breads, pasta and pizza, cakes and cookies and non-alcoholic beverages groups in both periods, differing in the rank order of the last two groups. Although being a country that has adopted mandatory folic acid flour fortification for almost two decades, increased POFI was observed in 2017–2018. This study brings significant scientific information, which can help understand folate dietary data in different contexts and consequently guide the approach for public health fortification strategies.

Maternal folic acid and vitamin B12 (B12) status during pregnancy influence fetal growth. This study elucidated the effect of altered dietary ratio of folic acid and B12 on the regulation of H19/IGF2 locus in C57BL/6 mice. Female mice were fed diets with nine combinations of folic acid and B12 for 4 weeks. They were mated and the offspring born (F1) were continued on the same diet for 6 weeks post-weaning and were allowed to mate. The placenta and fetal (F2) tissues were collected at day 20 of gestation. H19 overexpression observed under dietary deficiency of folate combined with normal B12 (B12 normal folic acid-deficient, BNFD) was associated with an increased expression of microRNA-675 (miR-675) in maternal and fetal tissues. Insulin-like growth factor 2 (IGF2) expression was decreased under folic acid-deficient conditions combined with normal, deficient or over-supplemented state of B12 (BNFD, BDFD and BOFD) in fetal tissues along with B12 deficiency combined with normal folic acid (BDFN) in the placenta. The altered expression of imprinted genes under folic acid-deficient conditions was related to decreased serum levels of folate and body weight (F1). Hypermethylation observed at the H19 differentially methylated region (DMR) (in BNFD) might be responsible for the decreased expression of IGF2 in female fetal tissues. IGF2 DMR2 was found to be hypomethylated and associated with low serum B12 levels with B12 deficiency in fetal tissues. Results suggest that the altered dietary ratio of folic acid and B12 affects the in utero development of the fetus in association with altered epigenetic regulation of H19/IGF2 locus.

The demand for cobalamin (vitamin B12) and folate is increased during pregnancy, and deficiency during pregnancy may lead to complications and adverse outcomes. Yet, the status of these micronutrients is unknown in many populations. We assessed the concentration of cobalamin, folate and their functional biomarkers, total homocysteine (tHcy) and methylmalonic acid (MMA), in 561 pregnant women enrolled in a community-based randomised controlled trial in Bhaktapur, Nepal. Plasma concentrations of cobalamin, folate, tHcy and MMA were measured and a combined indicator of vitamin B12 status (3cB12) was calculated. We report mean or median concentrations and the prevalence of deficiency according to commonly used cut-offs, and assessed their association with indicators of socio-economic status, and maternal and dietary characteristics by linear regression. Among the women at gestational week less than 15, deficiencies of cobalamin and folate were seen in 24 and 1 %, respectively. Being a vegetarian was associated with lower plasma cobalamin, and a higher socio-economic status was associated with a better micronutrient status. We conclude that cobalamin deficiency defined by commonly used cut-offs was common in Nepalese women in early pregnancy. In contrast, folate deficiency was rare. As there is no consensus on cut-off points for vitamin B12 deficiency during pregnancy, future studies are needed to assess the potential functional consequences of these low values.

Maternal folic acid (FA) plays an important role in the fetus development, but it is unknown the response of hepatic metabolism in the offspring from different litter sizes to maternal FA supplementation. In the present study, this was done by feeding the ewes with 0, 16 and 32 mg/(kg·DM) FA supplemented diet during pregnancy and analysing the hepatic one-carbon metabolism-related indices and gene expression in the neonatal lambs of different litter sizes (twins, TW; triplets, TR). Regardless of litter sizes, the concentrations of folate, methionine, S-adenosylmethionine and DNA methyltransferase increased significantly, but homocysteine and S-adenosylhomocysteine decreased in the liver of newborn lambs from ewes whose diet was supplemented with FA. In TW, maternal FA status has little effect on hepatic genes expression profile of newborn lambs, and no significant enriched pathway was found. However, DEG involved in cell proliferation such as CCNA2, CCNB2, CCNE2, CDK1 and BUB1 were significantly enriched when the ewes were supplemented with FA in TR groups. In addition, nucleotide synthesis-related genes such as POLD1, POLD2, MCM4 and MCM5 were enriched markedly in DNA replication and pyrimidine metabolism pathways in triplets when a higher FA ingestion [32 mg/(kg·DM)] was implemented in ewes. This finding demonstrated that the hepatic methyl metabolism in TW and TR newborn lambs was regulated by maternal FA status. The hepatic cell proliferation and nucleotide metabolism related genes in TR were more susceptible to maternal dietary FA supplementation during pregnancy.

To investigate the influences of cobalt (Co) and folic acid (FA) on growth performance and rumen fermentation, Holstein male calves (n 40) were randomly assigned to four groups according to their body weights. Cobalt sulphate at 0 or 0·11 mg Co/kg DM and FA at 0 or 7·2 mg/kg DM were used in a 2 × 2 factorial design. Average daily gain was elevated with FA or Co supplementation, but the elevation was greater for supplementing Co in diets without FA than with FA. Supplementing FA or Co increased DM intake and total-tract nutrient digestibility. Rumen pH was unaltered with FA but reduced with Co supplementation. Concentration of rumen total volatile fatty acids was elevated with FA or Co inclusion. Acetate percentage and acetate to propionate ratio were elevated with FA inclusion. Supplementing Co decreased acetate percentage and increased propionate percentage. Activities of xylanase and α-amylase and populations of total bacteria, fungi, protozoa, Ruminococcus albus, Fibrobacter succinogenes and Prevotella ruminicola increased with FA or Co inclusion. Activities of carboxymethyl-cellulase and pectinase increased with FA inclusion and population of methanogens decreased with Co addition. Blood folates increased and homocysteine decreased with FA inclusion. Blood glucose and vitamin B12 increased with Co addition. The data suggested that supplementing 0·11 mg Co/kg DM in diets containing 0·09 mg Co/kg DM increased growth performance and nutrient digestibility but had no improvement on the effects of FA addition in calves.

Folic acid (FA) can reduce the risk for selected birth defects other than neural tube defects. We examined whether FA has preventive effects against fetal abdominal wall defects (AWD) in a unique intervention cohort in China. Birth outcomes of 247 831 singleton births from a population-based cohort study with detailed pre-conceptional FA intake information were collected in China in 1993–1996. Information on births at 20 complete gestational weeks, including live births, stillbirths and pregnancy terminations, and all structural birth defects regardless of gestational week were recorded. The birth prevalence of omphalocele, gastroschisis and total fetal AWD was classified by maternal FA supplementation. The prevalence of total AWD was 4·30 per 10 000 births among women who took FA compared with 13·46 per 10 000 births among those who did not take FA in northern China and 6·28 and 5·18 per 10 000 births, respectively, in southern China. The prevalence of omphalocele was 0·54 per 10 000 births among women who took FA compared with 3·74 per 10 000 births among those who did not take FA in northern China and 1·79 and 1·44 per 10 000 births, respectively, in southern China. FA supplementation significantly prevented total AWD in multivariate analysis (relative risk 0·26, 95 % CI 0·11, 0·61) in northern China, although no preventive effect of FA on AWD was observed in southern China. FA supplementation successfully reduced the prevalence of AWD in northern China.

The present study was undertaken to evaluate the influence of rumen-protected folic acid (RPFA) on slaughter performance, visceral organ and gastrointestinal tract coefficients, and meat quality in lambs. Sixty-six lambs from 120 Hu ewes were selected based on body weight and maternal diets and then assigned to six groups using a randomised block experimental design in a 3 × 2 factorial arrangement. The first factor was folic acid (FA) as RPFA in the maternal diet (0 mg/kg (M0F), 16 mg/kg (M16F) or 32 mg/kg (M32F) on DM basis). The second factor was FA in the lambs’ diet from weaning until slaughter (0 mg/kg (OC) or 4·0 mg/kg (OF)). The results indicated that the addition of 16 mg/kg FA to the maternal diet increased pre-slaughter weight (PSW), dressing and meat percentage, the reticulum and omasum coefficients, length of the jejunum and ileum, tail fat and perirenal fat coefficient and a* value of the meat colour. The addition of RPFA to the lambs’ diet increased PSW, dressing and meat percentage, eye muscle area, abomasum weight, weight and length of the small intestine, but reduced the coefficients of tail fat. An M × O interaction was observed for the weights of heart, lungs, rumen and total stomach, weight and coefficient of omental fat and the girth rib value. Collectively, RPFA in the maternal and lambs’ diet improved slaughter performance and meat quality by stimulating the morphological development of the gastrointestinal tract and the distribution of fat in the body.

We aimed to examine whether baseline neutrophil counts affected the risk of new-onset proteinuria in hypertensive patients, and, if so, whether folic acid treatment is particularly effective in proteinuria prevention in such a setting. A total of 8208 eligible participants without proteinuria at baseline were analysed from the renal substudy of the China Stroke Primary Prevention Trial. Participants were randomised to receive a double-blind daily treatment of 10 mg of enalapril and 0·8 mg of folic acid (n 4101) or 10 mg of enalapril only (n 4107). The primary outcome was new-onset proteinuria, defined as a urine dipstick reading of ≥1+ at the exit visit. The mean age of the participants was 59·5 (sd, 7·4) years, 3088 (37·6 %) of the participants were male. The median treatment duration was 4·4 years. In the enalapril-only group, a significantly higher risk of new-onset proteinuria was found among participants with higher neutrophil counts (quintile 5; ≥4·8 × 109/l, OR 1·44; 95 % CI 1·00, 2·06), compared with those in quintiles 1–4. For those with enalapril and folic acid treatment, compared with the enalapril-only group, the new-onset proteinuria risk was reduced from 5·2 to 2·8 % (OR 0·49; 95 % CI 0·29, 0·82) among participants with higher neutrophil counts (≥4·8 × 109/l), whereas there was no significant effect among those with neutrophil counts <4·8 × 109/l. In summary, among hypertensive patients, those with higher neutrophil counts had increased risk of new-onset proteinuria, and this risk was reduced by 51 % with folic acid treatment.