Interaction between excess folate and low vitamin B12 status

Interaction and association between multiple vitamins and social adaptability and severity of autism: A large-scale retrospective study from China

Since children with autism spectrum disorder (ASD) often exhibit selective eating behaviors, it is generally believed that they may have abnormal nutrient structure, leading to aberrant concentrations of some serum vitamins. However, previous studies on serum vitamins in individuals with ASD are mixed. Additionally, the interaction and association between multiple serum vitamin and ASD-related symptoms remain unclear. This study utilized a cross-sectional survey with a large sample size (n = 1235) from China to clarify previous mixed findings, and examine the interaction and association between multiple serum vitamins (including folic acid [FA], vitamin A [VA], vitamin E [VE], vitamin B12 [VB12], and vitamin D [VD]) and social adaptability and symptom severity in children with ASD. Findings found that symptom severity was negatively associated with concentrations of serum VA, VE, VB12, and VD; while, social adaptability was significantly associated with the natural log-transformed concentrations of FA and VB12. Finding also revealed the interaction of VA and VE on the association between both vitamins and severity of ASD symptoms, as well as the interaction of VB12 and FA on the association between both vitamins and social adaptability. In particular, the combination of low concentration of VA and high concentration of VE is associated with the lowest risk of being "severely autistic"; while, the combination of low concentration of FA and high concentration of VB12 is associated with the lowest risk of being "poor social adaptability". This study offers the evidence for the requirement of considering multiple vitamins comprehensively, as well as valuable references for revealing the association between vitamin disparities and food selectivity in children with ASD.

Joint B Vitamin Intake and Type 2 Diabetes Risk: The Mediating Role of Inflammation in a Prospective Shanghai Cohort

BACKGROUND AND AIMS

Type 2 diabetes (T2D) is a global and complex public health challenge, and dietary management is acknowledged as critical in its prevention. Recent studies have highlighted the involvement of micronutrients in T2D pathophysiology; our study aims to assess the association between B vitamin intake and T2D risks and the mediating role of inflammation.

METHODS

In a prospective cohort design, data on B vitamins intake, including thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), folate (B9), and cobalamin (B12), was obtained using a validated food frequency questionnaire (FFQ), and blood inflammatory biomarkers were analyzed according to standard protocol in the local hospitals at baseline from 44,960 adults in the Shanghai Suburban Adult Cohort and Biobank (SSACB). Incident T2D cases were identified according to a physician's diagnosis or medication records from the electronic medical information system. We employed logistic and weighted quantile sum regression models to explore the associations of single and combined levels of B vitamins with T2D and mediation analyses to investigate the effects of inflammation.

RESULTS

Negative correlations between B vitamins and T2D were observed in the single-exposure models, except for B3. The analyses of joint exposure (B1, B2, B6, B9, and B12) also showed an inverse association (OR 0.80, 95% CI 0.71 to 0.88), with vitamin B6 accounting for 45.58% of the effects. Further mediation analysis indicated a mediating inflammatory impact, accounting for 6.72% of the relationship.

CONCLUSIONS

Dietary intake of B vitamins (B1, B2, B6, B9, B12) was associated with a reduced T2D risk partially mediated by inflammation in Shanghai residents.

The independent and joint associations of vitamin B12 and methylmalonic acid on the risk of mortality in individuals with metabolic dysfunction-associated steatotic liver disease

PURPOSE

To investigate the independent and joint associations of vitamin B12 and methylmalonic acid (MMA) with all-cause, cardiovascular disease (CVD), and cancer mortality in patients with metabolic dysfunction-associated steatotic liver disease (MASLD).

METHODS

We included 6797 individuals with MASLD from the U.S. National Health and Nutrition Examination Survey. Serum MMA was measured using gas/liquid chromatography-mass spectrometry. Serum vitamin B12 was measured using commercial kits. The separate and joint associations of dietary intake and serum vitamin B12 (cutoff: 400 pg/mL) and MMA (cutoff: 250 nmol/L) levels with mortality were assessed by Cox proportional hazards regression.

RESULTS

During a median follow-up of 9.3 years, 1604 deaths were documented, including 438 from CVD and 365 from cancer. In MASLD patients, dietary intake and serum vitamin B12 did not associate with mortality, while MMA was associated with a 1.35-fold increased risk of all-cause mortality (P-trend < 0.001). The adjusted hazard ratios for the joint association of vitamin B12 and MMA with all-cause and CVD mortality were 1 in the B12lowMMAlow group (reference), 1.02 (0.87-1.20) and 1.15 (0.90-1.47) in the B12highMMAlow group, 1.55 (1.29-1.86) and 1.84 (1.28-2.65) in the B12lowMMAhigh group, and 1.82 (1.49-2.21) and 2.28 (1.40-3.71) in the B12highMMAhigh group, respectively. The joint association was modified by serum folate (P-interaction = 0.001).

CONCLUSIONS

In MASLD patients, MMA rather than dietary and serum vitamin B12 was positively associated with all-cause mortality. The joint effect of high levels of MMA and vitamin B12 showed the strongest associations with all-cause and CVD mortality, with a significant interaction with serum folate.

Correlation analysis of maternal condition during pregnancy with head circumference and autism spectrum disorder: A propensity score-matched study

To determine whether health status during pregnancy is associated with autism spectrum disorder (ASD) and abnormal head circumference (HC) in the offspring. This study included 41 Han children with ASD who visited the Children's Health Clinic of the Second Hospital of Shandong University between March 2018 and February 2019, and 264 Han children with typical development (TD) who visited the clinic during the same period. Physical measurements were performed on the children. The questionnaire obtained information on maternal risk factors that may be related to the increased risk of ASD and folic acid (FA) supplementation. We designed an observational case-control study using propensity score matching and multivariate logistic regression analysis. The incidence of macrocephaly in the ASD group was 22.0%, significantly higher than that in the TD group (1.8%). The incidence of microcephaly in the ASD group was 17.1% (n = 7), significantly higher than that in the TD group (1.8%). The differences between the comparisons were statistically significant. Maternal FA supplementation during pregnancy was significantly associated with ASD (P < .05), with an odds ratio (95% confidence interval of 3.69 (1.76, 7.76)). Also was associated with macrocephaly (P < .05), odds ratio (95% confidence interval) were 8.13 (1.63, 40.61) and 4.16 (1.18, 14.60), respectively. The incidence of abnormal HC was higher in the ASD group than that in the TD group. Maternal FA supplementation during pregnancy may be negatively associated with the occurrence of ASD and abnormal HC in the offspring. Further examination of the role of maternal health status in the etiology of ASD is recommended.

Uncovering the Hidden Dangers and Molecular Mechanisms of Excess Folate: A Narrative Review

This review delves into the intricate relationship between excess folate (vitamin B9) intake, especially its synthetic form, namely, folic acid, and its implications on health and disease. While folate plays a pivotal role in the one-carbon cycle, which is essential for DNA synthesis, repair, and methylation, concerns arise about its excessive intake. The literature underscores potential deleterious effects, such as an increased risk of carcinogenesis; disruption in DNA methylation; and impacts on embryogenesis, pregnancy outcomes, neurodevelopment, and disease risk. Notably, these consequences stretch beyond the immediate effects, potentially influencing future generations through epigenetic reprogramming. The molecular mechanisms underlying these effects were examined, including altered one-carbon metabolism, the accumulation of unmetabolized folic acid, vitamin-B12-dependent mechanisms, altered methylation patterns, and interactions with critical receptors and signaling pathways. Furthermore, differences in the effects and mechanisms mediated by folic acid compared with natural folate are highlighted. Given the widespread folic acid supplementation, it is imperative to further research its optimal intake levels and the molecular pathways impacted by its excessive intake, ensuring the health and well-being of the global population.

Scientific opinion on the tolerable upper intake level for folate

Following a request from the European Commission (EC), the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the revision of the tolerable upper intake level (UL) for folic acid/folate. Systematic reviews of the literature were conducted to assess evidence on priority adverse health effects of excess intake of folate (including folic acid and the other authorised forms, (6S)-5-methyltetrahydrofolic acid glucosamine and l-5-methyltetrahydrofolic acid calcium salts), namely risk of cobalamin-dependent neuropathy, cognitive decline among people with low cobalamin status, and colorectal cancer and prostate cancer. The evidence is insufficient to conclude on a positive and causal relationship between the dietary intake of folate and impaired cognitive function, risk of colorectal and prostate cancer. The risk of progression of neurological symptoms in cobalamin-deficient patients is considered as the critical effect to establish an UL for folic acid. No new evidence has been published that could improve the characterisation of the dose-response between folic acid intake and resolution of megaloblastic anaemia in cobalamin-deficient individuals. The ULs for folic acid previously established by the Scientific Committee on Food are retained for all population groups, i.e. 1000 μg/day for adults, including pregnant and lactating women, 200 μg/day for children aged 1-3 years, 300 μg/day for 4-6 years, 400 μg/day for 7-10 years, 600 μg/day for 11-14 years and 800 μg/day for 15-17 years. A UL of 200 μg/day is established for infants aged 4-11 months. The ULs apply to the combined intake of folic acid, (6S)-5-methyltetrahydrofolic acid glucosamine and l-5-methyltetrahydrofolic acid calcium salts, under their authorised conditions of use. It is unlikely that the ULs for supplemental folate are exceeded in European populations, except for regular users of food supplements containing high doses of folic acid/5-methyl-tetrahydrofolic acid salts.

The Association Between the Imbalance of Single-Carbon Nutrients in Early Pregnancy and Gestational Diabetes Mellitus Risk is Influenced by Serum Selenium Status: A Cohort Study

Purpose

The role of imbalanced one-carbon nutrients in gestational diabetes mellitus (GDM) risk has garnered significant interest, yet existing studies yield inconsistent results. Our objective was to assess whether the association between an unbalanced ratio of folate to vitamin B12 and GDM risk is influenced by the status of other micronutrients.

Methods

This cohort study included 366 singleton-pregnancy Han women enrolled at the Shunyi District Maternal and Child Health Hospital in Beijing, China. During the first trimester of pregnancy, we measured red blood cell (RBC) folate, serum levels of vitamin B12, vitamin D, and selenium. We examined the association between the imbalanced status of RBC folate and vitamin B12 and GDM risk using logistic regression, stratified by serum selenium or vitamin D status.

Results

Among the 366 women, 67 (18.3%) were diagnosed with GDM, 201 (54.9%) had vitamin D deficiency, and 245 (66.9%) had selenium deficiency. Overall, women with higher RBC folate/vitamin B12 ratios did not exhibit a significantly higher risk of GDM compared to those in reference tertile (all P > 0.05). Subsequently, we divided women into deficient and non-deficient groups based on serum selenium or vitamin D levels. In women with selenium deficiency, those in the highest tertile of the RBC folate/vitamin B12 ratio had the highest odds of GDM [OR: 3.40 (1.16-9.97), P=0.026] after adjusting for covariates. However, similar findings were not observed in pregnancies with normal selenium status. Irrespective of vitamin D status, women with higher RBC folate/vitamin B12 ratios did not exhibit a significantly increased risk of GDM.

Conclusion

Micronutrient deficiencies are common in early pregnancy. Women with a higher folate/vitamin B12 ratio coupled with selenium deficiency in early pregnancy have a higher GDM risk. These findings underscore the importance of micronutrient assessment in early pregnancy and subsequent interventions for micronutrient deficiencies.

Folate and retinal vascular diseases

Folate, a pteroylglutamic acid derivative, participates in fundamental cellular metabolism. Homocysteine, an amino acid, serves as an intermediate of the methionine cycle and can be converted back to methionine. Hyperhomocysteinemia is a recognized risk factor for atherosclerotic and cardiovascular diseases. In recent decades, elevated plasma homocysteine levels and low folate status have been observed in many patients with retinal vascular diseases, such as retinal vascular occlusions, diabetic retinopathy, and age-related degeneration. Homocysteine-induced toxicity toward vascular endothelial cells might participate in the formation of retinal vascular diseases. Folate is an important dietary determinant of homocysteine. Folate deficiency is the most common cause of hyperhomocysteinemia. Folate supplementation can eliminate excess homocysteine in plasma. In in vitro experiments, folic acid had a protective effect on vascular endothelial cells against high glucose. Many studies have explored the relationship between folate and various retinal vascular diseases. This review summarizes the most important findings that lead to the conclusion that folic acid supplementation might be a protective treatment in patients with retinal vascular diseases with high homocysteine or glucose status. More research is still needed to validate the effect of folate and its supplementation in retinal vascular diseases.

Diverse associations observed between pregnancy complications and RBC or plasma folates determined by an in-house developed LC-MS/MS method

BACKGROUND

As folates are essential for embryonic development and growth, it is necessary to accurately determine the levels of folates in plasma and red blood cells (RBCs) for clinical intervention. The aims of this study were to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitation of folates in plasma and RBCs and to examine the association between plasma and RBC folate concentrations and gestational diabetes mellitus (GDM), gestational hypertension (GH) and preeclampsia (PE).

METHODS

With the in-house developed LC-MS/MS, a retrospective cross-sectional study was conducted. The healthy pregnant women of first- (n = 147), second- (n = 84) and third-trimester (n = 141) or the women diagnosed with GDM (n = 84), GH (n = 58) or PE (n = 23), that were aged between 22 and 46 years old and registered at our institute, were subjected for measurement of folic acid (FA) and 5-methyltetrahydrofolate (5-MTHF), followed by appropriate statistical association analysis.

RESULTS

The assay for simultaneous quantitation of FA and 5-MTHF in plasma and RBCs was linear, stable, with imprecision less than 15% and recoveries within ±10%. The lower limits of quantification for FA and 5-MTHF measurement in whole blood were 0.57 and 1.09 nmol/L, and in plasma were 0.5 and 1 nmol/L, respectively. In the association analysis, the patients with lower RBC folate level (<906 nmol/L) presented higher risks of PE development (OR 4.861 [95% CI 1.411-16.505]) by logistic regression and restricted cubic spline (RCS) regression in a nonlinear fashion. In addition, higher level of plasma folates in pregnancy was significantly associated with GH risk but may be protective for the development of GDM.

CONCLUSIONS

The in-house developed LC-MS/MS method for folates and metabolites in plasma or RBC showed satisfactory analytical performance for clinical application. Further, the levels of folates and metabolites were diversely associated with GDM, GH and PE development.

Knowledge domain and research trends for Gestational Diabetes Mellitus and nutrition from 2011 to 2021: a bibliometric analysis

Objective

Nutrient management and lifestyle changes are the frontlines of treatment for all pregnant women diagnosed with Gestational Diabetes Mellitus (GDM). This study aimed to identify the global research architecture, trends, and hotpots of GDM and nutrition.

Methods

We obtained publications from the sub-databases of Science Citation Index Expanded and Social Science Citation Index sourced from the Web of Science Core Collection database on January 4, 2022, using publication years between 2011 and 2021. CiteSpace software, VOSviewer, and Microsoft Excel 2019 were used to conduct the bibliometric analyses.

Results

A growing publication trend was observed for GDM and nutrition, and this field has great potential. More GDM and nutrition research has been conducted in developed countries than developing countries. The top three authors with a high publication frequency, co-citations, and a good h-index were from the United States. There were the four studies of randomized controlled trials (RCTs) or meta-analyses of RCTs, as well as one review in the top five items of cited literature. Keywords were categorized into four clusters based on the keywords visualization.

Conclusion

It is important to strengthen the collaboration between nations of different economies to produce more high-quality research on GDM and nutrition. It may be beneficial to further study the etiology, diagnosis, and treatment of GDM based on current results to provide a new perspective on GDM and nutrition.

High Serum Folate Concentration, Vitamin B12 Deficiency, and Anthropometric Nutritional Status in Brazilian Children Aged 6-59 Months: Data from the Brazilian National Survey of Child Nutrition

BACKGROUND

Vitamin B12 and folate are key nutrients that help children reach their full potential in growth and development; however, little is known about the status of these vitamins in Brazilian children.

OBJECTIVES

To describe the serum concentrations of vitamin B12 and folate, to investigate the association between high folate concentration (HFC) and vitamin B12 deficiency, and to evaluate the association between vitamin B12 and stunting/underweight in Brazilian children aged 6-59 mo.

METHODS

Data from 7417 children aged 6-59 mo collected during the Brazilian National Survey on Child Nutrition were used. Serum concentrations of vitamin B12 of <150 pmol/L and folate of <10 nmol/L were classified as deficient, and folate concentrations of >45.3 nmol/L were classified as HFC. Children with length/height-for-age z-score of less than -2 were considered stunted, and those with weight-for-age z-score of less than -2 were underweight. Logistic regression models were performed.

RESULTS

In Brazil, 14.2% (95% CI: 12.2, 16.1) of children aged 6-59 mo had vitamin B12 deficiency, 1.1% (95% CI: 0.5, 1.6) had folate deficiency, and 36.9% (95% CI: 33.4, 40.3) had HFC. Vitamin B12 deficiency was higher in children from the northern region of Brazil (28.5%), between 6 and 24 mo (25.3%), whose mothers had lower formal education (0-7 y; 18.7%). Children with HFC had 62% lower odds (OR: 0.38; 95% CI: 0.27, 0.54) of vitamin B12 deficiency than those with normal/deficient folate. Children with vitamin B12 deficiency and normal/deficient folate had higher odds of stunting (OR: 1.58; 95% CI: 1.02, 2.43) than children without vitamin B12 deficiency and normal/deficient folate.

CONCLUSIONS

Vitamin B12 deficiency is a public health problem among Brazilian children aged <2 y with vulnerable socioeconomic status. HFC was inversely associated with vitamin B12 deficiency, and lower odds of stunting were observed in children with HFC and vitamin B12 deficiency than in those with vitamin B12 deficiency and normal/deficient folate.

Association of serum water-soluble vitamin exposures with the risk of metabolic syndrome: results from NHANES 2003-2006

Introduction

Existing evidence suggests an association between certain vitamins and metabolic syndrome (MetS), but few epidemiological studies have focused on the effects of multivitamin co-exposure on MetS. This study aims to investigate the associations of the individual or multiple water-soluble vitamins (i.e., vitamin C (VC), vitamin B9 (VB9), and vitamin B12 (VB12)) with co-exposure to MetS, as well as the dose-response relationships among them.

Methods

A cross-sectional study was conducted by employing the National Health and Examination Surveys (NHANESs) 2003-2006. Multivariate-adjusted logistic regression models were used to explore the association between individual serum water-soluble vitamins and the risk of MetS and its components, including waist circumference, triglyceride, high-density lipoprotein, blood pressure, and fasting plasma glucose. Restricted cubic splines were performed to explore the dose-response relationships among them. The quantile g-computation method was adopted to explore the associations of multiple water-soluble vitamins co-exposure with MetS risk and MetS components.

Results

A total of 8983 subjects were involved in the study, of whom 1443 were diagnosed with MetS. The MetS groups had a higher proportion of participants with age ≥60 years, BMI ≥30 kg/m², and insufficient physical activity. Compared with the lowest quartile, the third (OR=0.67, 95% CI: 0.48, 0.94) and highest quartiles (OR=0.52, 95%CI: 0.35, 0.76) of VC were associated with lower MetS risk. Restricted cubic splines showed negative dose-response relationships among VC, VB9 and VB12, and MetS. Regarding MetS components, higher VC quartiles were associated with lower waist circumference, triglyceride, blood pressure, and fasting plasma glucose, while higher VC and VB9 quartiles were associated with higher high-density lipoprotein (HDL). Co-exposure to VC, VB9, and VB12 was significantly inversely associated with MetS, with ORs (95% CI) of 0.81 (0.74, 0.89) and 0.84 (0.78, 0.90) in the conditional and marginal structural models, respectively. Furthermore, we found that VC, VB9, and VB12 co-exposure were negatively associated with waist circumference and blood pressure, while VC, VB9, and VB12 co-exposure were positively associated with HDL.

Conclusion

This study revealed negative associations of VC, VB9, and VB12 with MetS, while the high water-soluble vitamin co-exposure was associated with a lower MetS risk.

Role of Prenatal Nutrition in the Development of Insulin Resistance in Children

Nutrition during the prenatal period is crucial for the development of insulin resistance (IR) and its consequences in children. The relationship between intrauterine environment, fetal nutrition and the onset of IR, type 2 diabetes (T2D), obesity and metabolic syndrome later in life has been confirmed in many studies. The intake of carbohydrates, protein, fat and micronutrients during pregnancy seems to damage fetal metabolism programming; indeed, epigenetic mechanisms change glucose-insulin metabolism. Intrauterine growth restriction (IUGR) induced by unbalanced nutrient intake during prenatal life cause fetal adipose tissue and pancreatic beta-cell dysfunction. In this review we have summarized and discussed the role of maternal nutrition in preventing insulin resistance in youth.

Reduced circulating folate among older adults caused by continuous work: nested cross-sectional study conducted in a country with folic acid fortification program

Population aging is 1 of the biggest challenges facing public health today, and cognitive dysfunction is an important concern. Cognitive impairment may be associated with high folate concentrations and low vitamin B₁₂ concentrations; the latter is a common problem among elderly people. Therefore, we hypothesized there was a high circulating folate concentration among older people living in a country with a mandatory folic acid fortification program. We conducted a cross-sectional study to investigate nutritional status of folate and vitamin B₁₂ among aged people. Three dietary recalls, serum folate (sfolate), erythrocyte (red blood cell) folate (RBC folate), and serum vitamin B₁₂ and homocysteine were collected. Linear regression models were used to investigate factors associated with circulating vitamins. We interviewed 169 participants. Half reported inadequate consumption of folate. However, RBC folate deficiency was observed in 27%, 13% in the serum, and a 10% excess of sfolate. One-quarter reported inadequate consumption of B_12, but only 5% had deficiency. Factors negatively associated with circulating folate were continuous work and smoking, and positively associated with polyunsaturated fatty acid. Factor negatively associated with the circulating B₁₂ were use of a dental prosthesis and intake of saturated fatty acid. Permanent investigation of excess of sfolate and B₁₂ deficiency, especially among older adults living in countries exposed to a mandatory folic acid fortification program, is important because of the possible relation to the cognitive function.

Vitamin B12 status and folic acid/vitamin B12 related to the risk of gestational diabetes mellitus in pregnancy: a systematic review and meta-analysis of observational studies

Background

This review was conducted to investigate the association between serum vitamin B12 levels as well as folic acid/vitamin B12 during pregnancy and the risk of gestational diabetes mellitus (GDM).

Methods

A comprehensive search of electronic databases (Embase, PubMed, and Web of Science) was performed. The odds ratios (ORs) with 95% confidence intervals (CIs) of GDM risk were summarized using a random effects model. We also performed subgroup analyses to explore the source of heterogeneity.

Results

A total of 10 studies, including 10,595 pregnant women were assessed. Women with vitamin B12 deficiency were at higher risk for developing GDM when compared with those who were vitamin B12 sufficient (OR, 1.46; 95% CI 1.21–1.79; I²: 59.0%). Subgroup analysis indicated that this association might differ based on sample size and geographical distribution. Elevated vitamin B12 levels may decrease the risk of GDM by 23%. The role of excess folic acid and low vitamin B12 levels in the occurrence of GDM is also controversial.

Conclusion

In summary, vitamin B12 deficiency is associated with increased risk of GDM, it is necessary to pay more attention to the balance of vitamin B12 and folic acid. However, more in-depth studies across multiple populations are needed to verify these results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04911-9.

High Folate, Perturbed One-Carbon Metabolism and Gestational Diabetes Mellitus

Folate is a dietary micronutrient essential to one-carbon metabolism. The World Health Organisation recommends folic acid (FA) supplementation pre-conception and in early pregnancy to reduce the risk of fetal neural tube defects (NTDs). Subsequently, many countries (~92) have mandatory FA fortification policies, as well as recommendations for periconceptional FA supplementation. Mandatory fortification initiatives have been largely successful in reducing the incidence of NTDs. However, humans have limited capacity to incorporate FA into the one-carbon metabolic pathway, resulting in the increasingly ubiquitous presence of circulating unmetabolised folic acid (uFA). Excess FA intake has emerged as a risk factor in gestational diabetes mellitus (GDM). Several other one-carbon metabolism components (vitamin B12, homocysteine and choline-derived betaine) are also closely entwined with GDM risk, suggesting a role for one-carbon metabolism in GDM pathogenesis. There is growing evidence from in vitro and animal studies suggesting a role for excess FA in dysregulation of one-carbon metabolism. Specifically, high levels of FA reduce methylenetetrahydrofolate reductase (MTHFR) activity, dysregulate the balance of thymidylate synthase (TS) and methionine synthase (MTR) activity, and elevate homocysteine. High homocysteine is associated with increased oxidative stress and trophoblast apoptosis and reduced human chorionic gonadotrophin (hCG) secretion and pancreatic β-cell function. While the relationship between high FA, perturbed one-carbon metabolism and GDM pathogenesis is not yet fully understood, here we summarise the current state of knowledge. Given rising rates of GDM, now estimated to be 14% globally, and widespread FA food fortification, further research is urgently needed to elucidate the mechanisms which underpin GDM pathogenesis.

Fetal hyperhomocysteinemia is associated with placental inflammation and early breakdown of maternal-fetal tolerance in Pre-term birth

PROBLEM

Hyperhomocysteinemia (hypHcy) due to impaired folate metabolism is shown to be a risk factor for preterm birth (PTB) and low birth weight (LBW) in mothers. However, the relationship of fetal hypHcy with adverse pregnancy outcomes is under-represented. The present study aims to investigate the association of fetal hypHcy with oxidative stress and placental inflammation that can contribute to an early breakdown of maternal-fetal tolerance in pre-term birth (PTB).

METHODS

Cord blood and placenta tissue were collected from PTB and term infant group. Levels of homocysteine, folic acid, vitamin B12 and oxidative stress markers (MDA, T-AOC, 8-OHdG) were measured in cord blood serum using ELISA and respective standard assay kits. Relative expression of candidate genes (TNF-α, IL-6, IL1-β, VEGF-A, MMP2 and MMP9) was also checked using RT-PCR and immunoblotting/immunohistochemistry.

RESULTS

PTB infants showed significantly higher levels of homocysteine (p = 0.02) and lower levels of vitamin B12 (p = 0.005) as compared to term infants. We also found that PTB infants with hypHcy had lower T-AOC (p = 0.003) and higher MDA (p = 0.04) levels as compared to term infants with normal homocysteine levels. The mRNA and protein levels of TNF-α, VEGF-A, MMP2 and MMP9 were significantly higher in hypHcy PTB infants.

CONCLUSION

Our results show that fetal hypHcy is associated with oxidative stress and an increase in inflammatory markers in the placenta. Thus, in conclusion, our study demonstrates that fetal hypHcy during pregnancy is a potential risk factor that may initiate an early breakdown of uterine quiescence due to activation of inflammatory processes leading to PTB. This article is protected by copyright. All rights reserved.

Effects of maternal folate and vitamin B12 on gestational diabetes mellitus: a dose-response meta-analysis of observational studies

To comprehensively estimate the association of gestational diabetes mellitus (GDM) risk with maternal red blood cell (RBC) folate, plasma/serum folate, dose and duration of folic acid supplement (FAS) intake and vitamin B12 separately. PubMed, Web of science, CNKI, and Wanfang Databases were searched through March 26, 2021. We synthesized data using random-effects model meta-analysis in Stata 12.0. Sensitivity, subgroup and dose-response analyses were also performed. The certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE). Twenty six datasets from thirteen eligible observational studies were included in the study. We found a significant increase of GDM risk with the highest versus lowest category of RBC folate (OR = 1.96, 95% CI: 1.48-2.61, I2 = 0.0%, moderate-certainty evidence) and plasma/serum folate (OR = 1.23, 1.02-1.48, I2 = 57.8%, low-certainty evidence). The dose-response analysis revealed that each 200 ng/ml increase in RBC folate was significantly associated with 8% higher GDM risk. No significant association between dose of FAS intake and GDM risk was found with very low cetainty. Meanwhile, longer duration (≥3 months) of FAS conferred 56% significant higher GDM risk (OR = 1.56, 1.02-2.39, very low certainty evidence). No significant association of GDM risk with highest plasma/serum B12 was observed compared to lowest B12 (OR = 0.77, 0.58-1.02, very low-certainty evidence). Moderate-certainty evidence suggests that higher RBC folate appears to significantly increase GDM risk. Higher plasma/serum folate may increase GDM risk but with low certainty. Further well-designed trials or prospective studies are needed.

Role of Vitamin B12 and Folate in Metabolic Syndrome

Metabolic syndrome (MS) is a collection of pathological metabolic conditions that includes insulin resistance, central or abdominal obesity, dyslipidemia, and hypertension. It affects large populations worldwide, and its prevalence is rising exponentially. There is no specific mechanism that leads to the development of MS. Proposed hypotheses range from visceral adiposity being a key factor to an increase in very-low-density lipoprotein and fatty acid synthesis as the primary cause of MS. Numerous pharmaceutical therapies are widely available in the market for the treatment of the individual components of MS. The relationship between MS and vitamin B complex supplementation, specifically folic acid and vitamin B12, has been a subject of investigation worldwide, with several trials reporting a positive impact with vitamin supplementation on MS.

In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Vitamin B12,” “Folate,” “Metabolic Syndrome,” and “Insulin Resistance.” We explored the literature on MS for its epidemiology, pathophysiology, newer treatment options, with a special focus on the effectiveness of supplementation with vitamins B9 and B12.

According to the literature, vitamin B12 and folate supplementation, along with a host of novel therapies, has a considerable positive impact on MS. These findings must be kept in mind while designing newer treatment protocols in the future.

Cobalamin and folate status in women during early pregnancy in Bhaktapur, Nepal

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.

Folic Acid and Autism: A Systematic Review of the Current State of Knowledge

Folic acid has been identified to be integral in rapid tissue growth and cell division during fetal development. Different studies indicate folic acid’s importance in improving childhood behavioral outcomes and underline its role as a modifiable risk factor for autism spectrum disorders. The aim of this systematic review is to both elucidate the potential role of folic acid in autism spectrum disorders and to investigate the mechanisms involved. Studies have pointed out a potential beneficial effect of prenatal folic acid maternal supplementation (600 µg) on the risk of autism spectrum disorder onset, but opposite results have been reported as well. Folic acid and/or folinic acid supplementation in autism spectrum disorder diagnosed children has led to improvements, both in some neurologic and behavioral symptoms and in the concentration of one-carbon metabolites. Several authors report an increased frequency of serum auto-antibodies against folate receptor alpha (FRAA) in autism spectrum disorder children. Furthermore, methylene tetrahydrofolate reductase (MTHFR) polymorphisms showed a significant influence on ASD risk. More clinical trials, with a clear study design, with larger sample sizes and longer observation periods are necessary to be carried out to better evaluate the potential protective role of folic acid in autism spectrum disorder risk.

Low vitamin B12 level in relation to trace element, total sialic acid and antioxidant enzymes in children with vitamin B12 deficiency anemia

In this study, children with vitamin B₁₂ deficiency anemia (V-B₁₂DA) and control subjects were evaluated for erythrocyte glutathione peroxidase, catalase and superoxide dismutase enzyme activities, glutathione, malondialdehyde, serum total sialic acid, total antioxidant status, cobalt, chromium, copper, selenium, vanadium, zinc, iron, lead, magnesium, calcium, sodium, potassium, chloride, phosphorus levels, and the associations of these variables were assessed. The study included 50 children with V-B₁₂DA and 50 control subjects. It was found that the V-B₁₂DA group was significantly lower than the control group, with regard to the mean±the standard error of the mean levels of cobalt (0.089±0.009; 0.058±0.0063 μmol/L, p<0.01), selenium (2.19±0.087; 1.88±0.057 μmol/L, p<0.01), vanadium (1.31±0.053; 1.18±0.035 μmol/L, p<0.05), magnesium (3.02±0.15; 2.73±0.068 μmol/L, p<0.05), zinc (50.76±1.96; 42.23± 1.53 μmol/L, p<0.001), and vitamin B₁₂ (427.20±21.45; 157.08±3.96 pg/mL, p<0.001). Moreover, a significant elevation in total sialic acid (1.44±0.050; 1.61±0.043 mmol/L, p<0.01), and mean corpuscular volume (MCV) (75.37±0.95; 79.91±1.14 fL, p<0.01). It was observed that in the V-B₁₂DA, significantly linear correlations were observed between cobalt - vitamin B₁₂ (r=0.334; p=0.025), vanadium - MCV (r=0.315; p=0.017), vitamin B₁₂ - MCV (r=-0.297; p=0.026). The findings of the study indicated that the levels of cobalt, vanadium significantly associated with traditional vitamin B_12-deficiency parameters. Vitamin B₁₂ and MCV should be measured together with cobalt, vanadium for monitoring the vitamin B₁₂ deficiency anemia.

Contribution of genetic ancestry and polygenic risk score in meeting vitamin B12 needs in healthy Brazilian children and adolescents

Polymorphisms in genes related to the metabolism of vitamin B12 haven’t been examined in a Brazilian population. To (a) determine the correlation between the local genetic ancestry components and vitamin B12 levels using ninety B12-related genes; (b) determine associations between these genes and their SNPs with vitamin B12 levels; (c) determine a polygenic risk score (PRS) using significant variants. This cross-sectional study included 168 children and adolescents, aged 9–13 years old. Total cobalamin was measured in plasma. Genotyping arrays and whole exome data were combined to yield ~ 7000 SNPs in 90 genes related to vitamin B12. The Efficient Local Ancestry Inference was used to estimate local ancestry for African (AFR), Native American, and European (EUR). The association between the genotypes and vitamin B12 levels were determined with generalized estimating equation. Vitamin B12 levels were driven by positive (EUR) and negative (AFR, AMR) correlations with genetic ancestry. A set of 36 variants were used to create a PRS that explained 42% of vitamin level variation. Vitamin B12 levels are influenced by genetic ancestry and a PRS explained almost 50% of the variation in plasma cobalamin in Brazilian children and adolescents.

Investigating the causal effect of maternal vitamin B12 and folate levels on offspring birthweight

Background

Lower maternal serum vitamin B12 (B12) and folate levels have been associated with lower offspring birthweight, in observational studies. The aim of this study was to investigate whether this relationship is causal.

Methods

We performed two-sample Mendelian randomization (MR) using summary data on associations between genotype-B12 (10 genetic variants) or genotype-folate (four genetic variants) levels from: a genome-wide association study of 45 576 individuals (sample 1); and both maternal- and fetal-specific genetic effects on offspring birthweight from the latest Early Growth Genetics consortium meta-analysis with 297 356 individuals reporting their own birthweight and 210 248 women reporting their offspring's birthweight (sample 2). We used the inverse variance weighted method, and sensitivity analyses to account for pleiotropy, in addition to excluding a potentially pleiotropic variant in the FUT2 gene for B12 levels.

Results

We did not find evidence for a causal effect of maternal or fetal B12 levels on offspring birthweight. The results were consistent across the different methods. We found a positive causal effect of maternal folate levels on offspring birthweight [0.146 (0.065, 0.227), which corresponds to an increase in birthweight of 71 g per 1 standard deviation higher folate]. We found some evidence for a small inverse effect of fetal folate levels on their own birthweight [−0.051 (−0.100, −0.003)].

Conclusions

Our results are consistent with evidence from randomized controlled trials that higher maternal folate levels increase offspring birthweight. We did not find evidence for a causal effect of B12 levels on offspring birthweight, suggesting previous observational studies may have been confounded.

Hyperhomocysteinemia and low vitamin B12 are associated with the risk of early pregnancy loss: A clinical study and meta-analyses

One-carbon metabolism is crucial for the maintenance of healthy pregnancy and alterations in this pathway have been associated with various pregnancy-related complications. Therefore, the present study was conducted to test the hypothesis that the altered folic acid, vitamin B12 and homocysteine levels are associated with the risk of early pregnancy loss (EPL). Plasma folic acid, vitamin B12 and homocysteine levels were analyzed in 83 females with EPL and 70 healthy pregnant females in their first trimester. Further, meta-analyses of folic acid, vitamin B12 and homocysteine were also performed involving various eligible studies. Results from our case-control study and meta-analysis showed that folic acid deficiency is not associated with the risk of EPL. On the other hand, low vitamin B12 and hyperhomocysteinemia were individually found to be significant risk factors for EPL in the present study (P < .01, P < .05, respectively) and meta-analysis as well (P < .001, P < .05, respectively). Vitamin B12 deficiency in combination with hyperhomocysteinemia was a more serious risk factor for EPL (Odds Ratio = 4.98, P = 0.002). Therefore, we conclude that vitamin B12 deficiency and elevated homocysteine levels are independent risk factors for EPL, and of higher risk when combined. The assessment of vitamin B12 and homocysteine levels may serve as a good screening marker for EPL risk.

Immunomodulatory diet in pediatric age

In the last few decades, the importance of a functioning immune system and health status has become more evident. Multiple factors are able to influence the development of chronic diseases and diet is one of the most important environmental factors. Evidence demonstrates that dietary patterns high in fat and low in fiber are associated with the development of non-communicable diseases. Moreover, optimal nutritional status can modulate immune maturation and response to inflammation. During inflammatory conditions, nutritional deficiencies may occur, establishing a vicious circle, consequently a balanced nutritional status is essential to prevent and counteract infections. Dietary diversity can prevent allergic diseases and nutrients such as DHA, arginine, vitamins and trace elements have an impact on physical barriers (such as gut mucosal barrier and skin), on the immune system response and on microbiome modulation. Protein deficiencies can compromise innate and adaptive immune functions; arginine availability can affect the immune response in injured states and other disease processes; EPA and DHA can modulate both innate and adaptive immunity; prebiotics have a beneficial effect on the functioning of the immune system. Zinc, copper, selenium and iron are involved in the correct development and function of the immune system. Vitamins D, E, A, B and C have a role on immune system through different mechanisms of action. Since a complex interplay exists between diet, microbiome and epigenetic factors which determine nutrient-induced changes on the immune function, the effect of each single nutrient may be difficult to study. Well-designed intervention studies, investigating the effects of whole dietary pattern, should be performed to clarify impact of foods on the immune function and disease risk.

The Level of Serum Pepsinogen in Diagnosing and Evaluating the Severity of Subacute Combined Degeneration Due to Vitamin B12 Deficiency

Subacute combined degeneration (SCD) is a neurological complication of cobalamin deficiency, which is usually caused by chronic autoimmune atrophic gastritis. Serum pepsinogen 1 and the ratio of pepsinogen 1/pepsinogen 2 (PG1/2) can reflect the severity of gastric atrophy.

Objective: This work aims to investigate whether decreased serum PG1 and PG1/2 ratio are helpful in diagnosing SCD and reflecting the severity of SCD.

Methods: We retrospectively analyzed the clinical and laboratory tests of 65 cases of SCD due to vitamin B12 deficiency and compared the laboratory parameters of SCD with 65 age- and sex-matched amyotrophic lateral sclerosis (ALS) patients.

Results: PG1 and PG1/2 ratio were decreased in 80 and 52.3% of SCD patients, respectively. Compared to patients with PG1/2 ratio ≥3.0, patients with PG1/2 ratio <3.0 had more severe anemia, larger mean corpuscular volume (MCV), lower level of vitamin B12, higher folate and homocysteine (Hcy), more severe changes in somatosensory evoked potential (SEP), and higher rate of lesions in spinal MRI (P < 0.05). PG1 and PG1/2 ratio had inverse correlation with MCV and N20 latency in SEP examination (P < 0.05). PG1/2 ratio, RBC count, and Hcy were independent risk factors for SCD in logistic regression analyses. The ROC curve analysis revealed that the diagnostic accuracy of PG1 and PG1/2 ratio was 72.2 and 73.0%, respectively, while the cutoff values were 22.4 ng/ml and 2.43 for SCD, respectively.

Conclusions: Decreased PG1 and PG1/2 ratio are helpful for the diagnosis and evaluation of the severity of SCD due to vitamin B12 deficiency.

Maternal Vitamin B12 Status and Risk of Cleft Lip and Cleft Palate Birth Defects in Tamil Nadu State, India

BACKGROUND AND OBJECTIVE

The causal role of maternal nutrition in orofacial clefts is uncertain. We tested hypotheses that low maternal vitamin B₁₂ and low folate status are each associated with an increased risk of isolated cleft lip with or without cleft palate (CL±P) in a case-control study in Tamil Nadu state, India.

METHODS

Case-mothers of CL±P children (n = 47) and control-mothers of unaffected children (n = 50) were recruited an average of 1.4 years after birth of the index child and plasma vitamin B₁₂, methylmalonic acid (MMA), total homocysteine (tHcy), and folate were measured at that time. Logistic regression analyses estimated associations between nutrient biomarkers and case-control status.

RESULTS

Odds ratios (ORs) contrasting biomarker levels showed associations between case-mothers and low versus high plasma vitamin B₁₂ (OR = 2.48, 95% CI, 1.02-6.01) and high versus low plasma MMA, an indicator of poor B₁₂ status (OR = 3.65 95% CI, 1.21-11.05). Case-control status was not consistently associated with folate or tHcy levels. Low vitamin B₁₂ status, when defined by a combination of both plasma vitamin B₁₂ and MMA levels, had an even stronger association with case-mothers (OR = 6.54, 95% CI, 1.33-32.09).

CONCLUSIONS

Mothers of CL±P children in southern India were 6.5 times more likely to have poor vitamin B₁₂ status, defined by multiple biomarkers, compared to control-mothers. Further studies in populations with diverse nutritional backgrounds are required to determine whether poor maternal vitamin B₁₂ or folate levels or their interactions are causally related to CL±P.

Vitamin B12 and Folate Status in Cognitively Healthy Older Adults and Associations with Cognitive Performance

OBJECTIVES

To determine prevalence of vitamin B12 and folate deficiency and associations with cognitive performance in participants recruited for the Cognitive Health in Ageing Register: Investigational, Observational, and Trial Studies in Dementia Research: Prospective Readiness cOhort Study (CHARIOTPRO) SubStudy (CPRO-SS).

DESIGN

Cross-sectional analysis of data collected in the screening phase for the CPRO-SS.

SETTING

Participants were recruited from the Chariot Register at Imperial College London comprising approximately 39,000 community dwelling volunteers.

PARTICIPANTS

Community dwelling individuals aged 60-85 years with B vitamin biomarker measures available were included (n=1946). After medical history and other exclusions, 1347 cognitively healthy participants were included for analysis of cognitive data.

MEASUREMENTS

Cognitive status was assessed with the Repeatable Battery for Neuropsychological Status (RBANS). Assays included vitamin B12 and folate, followed by serum methylmalonic acid and homocysteine levels for those with low vitamin B12. Gender-specific linear regression analysis was performed for associations between cognition and biomarkers. Non-gender specific regression for groups graded by B vitamin deficiency severity were also performed.

RESULTS

Vitamin B12 deficiency (<148pmol/L) was found in 17.2% of individuals and folate deficiency (<10nmol/L) in 1% of our participants. Low vitamin B12 was associated with poorer memory (p<0.03) in men. A high BMI predicted poorer attention and visuospatial indices (p<0.05). A regression analysis by B12 level revealed associations with poorer attention (β -6.46; p=0.004) for the deficient group and with immediate memory (β -2.99; p=0.019) for those categorised as severely deficient.

CONCLUSION

Older men and women are prone to vitamin B12 deficiency with associated subtle and different domain-specific disruptive effects in measures of memory and attention. Elevated homocysteine and methylmalonic acid contributed to poorer cognitive performance. Novel groups at particular risk of cognitive deficit were identified for future interventional studies in this field.

Association of Maternal Folate and Vitamin B12 in Early Pregnancy With Gestational Diabetes Mellitus: A Prospective Cohort Study

OBJECTIVE

To investigate the association of folate and vitamin B₁₂ in early pregnancy with gestational diabetes mellitus (GDM) risk.

RESEARCH DESIGN AND METHODS

The data of this study were from a subcohort within the Shanghai Preconception Cohort Study. We included pregnancies with red blood cell (RBC) folate and vitamin B₁₂ measurements at recruitment (between 9 and 13 gestational weeks) and those with three samples available for glucose measurements under an oral glucose tolerance test. GDM was diagnosed between 24 and 28 weeks' gestation. Odds ratio (OR) and 95% CI of having GDM was used to quantify the association.

RESULTS

A total of 1,058 pregnant women were included, and GDM occurred in 180 (17.01%). RBC folate and vitamin B₁₂ were significantly higher in pregnancies with GDM than those without GDM (P values were 0.045 and 0.002, respectively) and positively correlated with 1-h and 2-h serum glucose. Daily folic acid supplementation in early pregnancy increases the risk of GDM; OR (95% CI) was 1.73 (1.19-2.53) (P = 0.004). Compared with RBC folate <400 ng/mL, pregnancies with RBC folate ≥600 ng/mL were associated with ∼1.60-fold higher odds of GDM; the adjusted OR (95% CI) was 1.58 (1.03-2.41) (P = 0.033). A significant trend of risk effect on GDM risk across categories of RBC folate was observed (P _trend = 0.021). Vitamin B₁₂ was significantly associated with GDM risk (OR 1.14 per 100 pg/mL; P = 0.002). No significant association of serum folate and percentile ratio of RBC folate/vitamin B₁₂ with GDM was observed.

CONCLUSIONS

Higher maternal RBC folate and vitamin B₁₂ levels in early pregnancy are significantly associated with GDM risk, while the balance of folate/vitamin B₁₂ is not significantly associated with GDM.

B Vitamins and Their Role in Immune Regulation and Cancer

B group vitamins represent essential micronutrients for myriad metabolic and regulatory processes required for human health, serving as cofactors used by hundreds of enzymes that carry out essential functions such as energy metabolism, DNA and protein synthesis and other critical functions. B vitamins and their corresponding vitamers are universally essential for all cellular life forms, from bacteria to humans. Humans are unable to synthesize most B vitamins and are therefore dependent on their diet for these essential micronutrients. More recently, another source of B vitamins has been identified which is derived from portions of the 10¹³ bacterial cells inhabiting the gastrointestinal tract. Here we review the expanding literature examining the relationship between B vitamins and the immune system and diverse cancers. Evidence of B vitamin’s role in immune cell regulation has accumulated in recent years and may help to clarify the disparate findings of numerous studies attempting to link B vitamins to cancer development. Much work remains to be carried out to fully clarify these relationships as the complexity of B vitamins’ essential functions complicates an unequivocal assessment of their beneficial or detrimental effects in inflammation and cancers.

Knowledge gaps in understanding the metabolic and clinical effects of excess folates/folic acid: a summary, and perspectives, from an NIH workshop

Folate, an essential nutrient found naturally in foods in a reduced form, is present in dietary supplements and fortified foods in an oxidized synthetic form (folic acid). There is widespread agreement that maintaining adequate folate status is critical to prevent diseases due to folate inadequacy (e.g., anemia, birth defects, and cancer). However, there are concerns of potential adverse effects of excess folic acid intake and/or elevated folate status, with the original concern focused on exacerbation of clinical effects of vitamin B-12 deficiency and its role in neurocognitive health. More recently, animal and observational studies have suggested potential adverse effects on cancer risk, birth outcomes, and other diseases. Observations indicating adverse effects from excess folic acid intake, elevated folate status, and unmetabolized folic acid (UMFA) remain inconclusive; the data do not provide the evidence needed to affect public health recommendations. Moreover, strong biological and mechanistic premises connecting elevated folic acid intake, UMFA, and/or high folate status to adverse health outcomes are lacking. However, the body of evidence on potential adverse health outcomes indicates the need for comprehensive research to clarify these issues and bridge knowledge gaps. Three key research questions encompass the additional research needed to establish whether high folic acid or total folate intake contributes to disease risk. 1) Does UMFA affect biological pathways leading to adverse health effects? 2) Does elevated folate status resulting from any form of folate intake affect vitamin B-12 function and its roles in sustaining health? 3) Does elevated folate intake, regardless of form, affect biological pathways leading to adverse health effects other than those linked to vitamin B-12 function? This article summarizes the proceedings of an August 2019 NIH expert workshop focused on addressing these research areas.

Safety and efficacy of supplements in pregnancy

Pregnancy is a time where expectant mothers often focus on their diet to improve their own health and to preserve the future health of their children. There is much conflicting information in the public domain about the safety and/or efficacy of nutritional supplements during pregnancy. Despite this, the market for supplements is growing. This review discusses the roles of critical nutrients in pregnancy and the available evidence on the use of supplements to reduce risks and improve maternal and fetal outcomes. Recommendations are made for pregnant women, taking into account safety data and tolerable upper intakes set for pregnant women. It is important for dieticians, nutritionists, physicians, and other healthcare providers to be able to offer accurate and evidence-based advice on supplement use in pregnancy. Routine supplementation may not be necessary for all, but individuals at risk are identified.

Dynamics and interactions of cobalamin and folate status during advanced aging - a longitudinal study in a community-dwelling cohort with multiple follow-ups

BACKGROUND

Older people are reported to be prone to imbalances between cobalamin and folate status with possible adverse effects on health. This longitudinal study investigates dynamics and interactions of cobalamin and folate status in a cohort of community-dwelling older adults by considering possible influencing factors.

METHODS

In total, 332 subjects ≥ 60 years were investigated over a mean observation period of 12 years. Data collection included serum cobalamin, folate and creatinine, dietary intakes of cobalamin, folate and alcohol, use of supplements, body composition, smoking behavior, and diseases. Linear mixed-effects models with repeated measurements were used to investigate the influence of variables on serum cobalamin and folate.

RESULTS

At baseline, median cobalamin intake exceeded the dietary reference value (DRV), while median folate intake was considerably below DRV. In most subjects, serum concentrations of both vitamins were within reference ranges. For serum cobalamin, apart from supplement use (Parameter estimate [95% confidence interval]: 130.17 [53.32, 207.01]), the main positive predictor was serum folate (4.63 [2.64, 6.62]). For serum folate, serum creatinine (10.85 [4.85, 16.86]), use of supplements (7.86 [5.05, 10.67]), serum cobalamin (0.01 [< 0.01, 0.01]), and dietary folate intake (0.02 [0.01, 0.03]) were positive predictors. No main effects of age, sex, body composition, alcohol intake or smoking were found after adjusting for simultaneous inference.

CONCLUSIONS

Advancing age, per se, is no risk factor for a decline in serum concentrations of cobalamin or folate in subjects ≥ 60 years. Suboptimal folate intake may limit the function of folate regarding the supply of methyl groups for methylation of cobalamin and subsequent creatine biosynthesis. The positive association of serum creatinine with folate deserves further exploration with regard to its possible relevance for maintaining energy dependent functional integrity in the course of ageing.

Valproate and folate: Congenital and developmental risks

Increasing awareness of the congenital and developmental risks associated with the use of sodium valproate (VPA) has led to recent European guidelines designed to avoid the use of this drug in pregnancy if effective alternative treatments are available. In the general population, it is well established that periconceptual folic acid reduces the risk of neural tube defects (NTDs) and possibly other congenital abnormalities. We here review the evidence 1) that VPA interferes with one-carbon metabolism, including the transport of methylfolate into the brain and the placenta by targeting folate receptors; 2) that VPA effects on the folate metabolic system contribute to congenital and developmental problems associated with VPA exposure; and 3) that genetic factors, notably polymorphisms related to one-carbon metabolism, contribute to the vulnerability to these VPA-induced risks. Based on these facts, we propose that the standard periconceptual use of 400 μg of folic acid may not adequately protect against VPA or other antiepileptic drug (AED)-induced congenital or developmental risks. Pending definitive studies to determine appropriate dose, we recommend up to 5 mg of folic acid periconceptually in at-risk women with the caveat that the addition of supplementary vitamin B12 may also be prudent because vitamin B12 deficiency is common in pregnancy in some countries and is an additional risk factor for developmental abnormalities.

The effect of the systemic folic acid intake as an adjunct to scaling and root planing on clinical parameters and homocysteine and C-reactive protein levels in gingival crevicular fluid of periodontitis patients: A randomized placebo-controlled clinical trial

AIM

To evaluate clinical and biochemical effects of adjunctive systemic folic acid (FA) intake with scaling and root planing (SRP) in periodontitis treatment.

MATERIALS AND METHODS

Sixty periodontitis subjects (30 per group) were randomly assigned into study groups and treated with either SRP + placebo (SRP + P) or SRP + folic acid (SRP + F). In addition to clinical parameters (plaque index [PI], gingival index [GI], probing pocket depth [PPD], clinical attachment level [CAL] and gingival recession [GR]), gingival crevicular fluid (GCF) samples were obtained at baseline and post-treatment (PT) periods (one (PT-1), three (PT-3) and six (PT-6) months) for C-reactive protein (CRP) and homocysteine (Hcy) evaluation.

RESULTS

Significant time-dependent reduction was detected at all clinical parameters for both groups (p < .001). Compared to SRP + P, CAL was lower in SRP + F at PT-1 (p = .004) and PT-3 (p = .035), whereas GR was lower at only PT-1 (p = .015). GCF volume and CRP did not show inter-group differences, whereas Hcy was higher in SRP + F at PT-3 (p = .044) and PT-6 (p = .041). GCF volume and Hcy showed reduction after treatment in both groups (p < .001).

CONCLUSION

Both modalities exhibited clinical improvement and change in biochemical parameters. Adjunctive systemic FA intake may be recommended adjunctive to periodontitis treatment to reveal better outcomes. However, its impact mechanisms should be further enlightened.

Fatty acid and lipid metabolism in liver of pregnant mice and their offspring is influenced by unbalanced folates/vitamin B12 diets

Micronutrients (folates and vitamin B12) and long chain polyunsaturated fatty acids (LC-PUFAs) are linked through the one carbon cycle. We studied the effects of pre and postnatal high FA/low B12 diets (HFLB12) on hepatic fatty acid metabolism. Pregnant C57BL/6 mice were divided in two groups: control (2 mg folic acid: FA/25 µg vitamin B12/Kg food) and HFLB12 diets (8 mg FA/5 µg vitamin B12/Kg food). Offspring continued on the same diets until 60 days old. We determined hepatic fatty acid profile in dams and offspring and the expression of PPARα, Cpt-1, Acox-1 and Fas and the enzymatic activity of desaturases, all involved in lipid metabolism. In liver of dams, the HFHB12 diet decreased total fatty acids and desaturase activities; in offspring, effects were opposite, being more noticeable in females. Prenatal and postnatal unbalanced folic acid/B12 diets play a crucial role in regulating genes and enzymes involved in lipid metabolism in liver of dams and their offspring in adulthood.

Maternal blood folate status during early pregnancy and occurrence of autism spectrum disorder in offspring: a study of 62 serum biomarkers

BACKGROUND

Autism spectrum disorder (ASD) evolves from an interplay between genetic and environmental factors during prenatal development. Since identifying maternal biomarkers associated with ASD risk in offspring during early pregnancy might result in new strategies for intervention, we investigated maternal metabolic biomarkers in relation to occurrence of ASD in offspring using both univariate logistic regression and multivariate network analysis.

METHODS

Serum samples from 100 women with an offspring diagnosed with ASD and 100 matched control women with typically developing offspring were collected at week 14 of pregnancy. Concentrations of 62 metabolic biomarkers were determined, including amino acids, vitamins (A, B, D, E, and K), and biomarkers related to folate (vitamin B₉) metabolism, lifestyle factors, as well as C-reactive protein (CRP), the kynurenine-tryptophan ratio (KTR), and neopterin as markers of inflammation and immune activation.

RESULTS

We found weak evidence for a positive association between higher maternal serum concentrations of folate and increased occurrence of ASD (OR per 1 SD increase: 1.70, 95% CI 1.22-2.37, FDR adjusted P = 0.07). Multivariate network analysis confirmed expected internal biochemical relations between the biomarkers. Neither inflammation markers nor vitamin D₃ levels, all hypothesized to be involved in ASD etiology, displayed associations with ASD occurrence in the offspring.

CONCLUSIONS

Our findings suggest that high maternal serum folate status during early pregnancy may be associated with the occurrence of ASD in offspring. No inference about physiological mechanisms behind this observation can be made at the present time because blood folate levels may have complex relations with nutritional intake, the cellular folate status and status of other B-vitamins. Therefore, further investigations, which may clarify the potential role and mechanisms of maternal blood folate status in ASD risk and the interplay with other potential risk factors, in larger materials are warranted.

Folate and vitamin B-12 deficiencies additively impaired memory function and disturbed the gut microbiota in amyloid-β infused rats

Folate and vitamin B12(V-B12) deficiencies are associated with metabolic diseases that may impair memory function. We hypothesized that folate and V-B12 may differently alter mild cognitive impairment, glucose metabolism, and inflammation by modulating the gut microbiome in rats with Alzheimer's disease (AD)-like dementia. The hypothesis was examined in hippocampal amyloid-β infused rats, and its mechanism was explored. Rats that received an amyloid-β(25-35) infusion into the CA1 region of the hippocampus were fed either control(2.5 mg folate plus 25 μg V-B12/kg diet; AD-CON, n = 10), no folate(0 folate plus 25 μg V-B12/kg diet; AD-FA, n = 10), no V-B12(2.5 mg folate plus 0 μg V-B12/kg diet; AD-V-B12, n = 10), or no folate plus no V-B12(0 mg folate plus 0 μg V-B12/kg diet; AD-FAB12, n = 10) in high-fat diets for 8 weeks. AD-FA and AD-VB12 exacerbated bone mineral loss in the lumbar spine and femur whereas AD-FA lowered lean body mass in the hip compared to AD-CON(P < 0.05). Only AD-FAB12 exacerbated memory impairment by 1.3 and 1.4 folds, respectively, as measured by passive avoidance and water maze tests, compared to AD-CON(P < 0.01). Hippocampal insulin signaling and neuroinflammation were attenuated in AD-CON compared to Non-AD-CON. AD-FAB12 impaired the signaling (pAkt→pGSK-3β) and serum TNF-α and IL-1β levels the most among all groups. AD-CON decreased glucose tolerance by increasing insulin resistance compared to Non-AD-CON. AD-VB12 and AD-FAB12 increased insulin resistance by 1.2 and 1.3 folds, respectively, compared to the AD-CON. AD-CON and Non-AD-CON had a separate communities of gut microbiota. The relative counts of Bacteroidia were lower and those of Clostridia were higher in AD-CON than Non-AD-CON. AD-FA, but not V-B12, separated the gut microbiome community compared to AD-CON and AD-VB12(P = 0.009). In conclusion, folate and B-12 deficiencies impaired memory function by impairing hippocampal insulin signaling and gut microbiota in AD rats.

Association of maternal folate status in the second trimester of pregnancy with the risk of gestational diabetes mellitus

Interest in the high folate status of pregnant women has increased due to its role in the prevention of neural tube defects (NTDs). The effect of increased red blood cell (RBC) folate status during the second trimester of pregnancy on gestational diabetes mellitus (GDM) remains unclear. We measured RBC folate concentrations by competitive protein-binding assay and obtained clinical information from electronic medical records. Logistic regression analysis was used to explore the associations of RBC folate concentrations with risks of gestational diabetes mellitus (GDM). We further assessed the potential nonlinear relations between continuous log-transformed RBC folate concentrations and GDM risk by using the restricted cubic splines. We observed high RBC folate concentrations in GDM patients compared to control group [median (interquartile range, IQR), GDM vs. controls: 1,554.03 (1,240.54-1,949.99) vs. 1,478.83 (1,124.60-1,865.71) nmol/L, p = .001]. Notably, high folate concentrations were significantly associated with an increased risk of GDM [RR per 1-SD increase: 1.16 (1.03, 1.30), p = .012] after adjustment for maternal age, parity, and body mass index (BMI) at enrollment. In the restricted cubic spline model, a test of the null hypothesis of the linear relationship was rejected (p = .001). Our study firstly showed that maternal RBC folate concentrations during the second trimester of pregnancy increase the risk of GDM in a Chinese population. Further randomized clinical trials (RCTs) are warranted to confirm the adverse effect.

Diet in Early Pregnancy: Focus on Folate, Vitamin B12, Vitamin D, and Choline

Purpose: Prenatal multivitamins are recommended in pregnancy. This study assessed food and supplement intakes of folate, vitamin B12 (B12), vitamin D, and choline in pregnant women living in Southern Ontario in comparison with current recommendations. Methods: Women recruited to the Be Healthy in Pregnancy RCT (NCT01693510) completed 3-day diet/supplement records at 12-17 weeks gestation. Intakes of folate, B12, vitamin D, and choline were quantified and compared with recommendations for pregnant women. Results: Folate intake (median (min, max)) was 1963 μg/day dietary folate equivalents (153, 10 846); 90% of women met the Estimated Average Requirement (EAR) but 77% exceeded the Tolerable Upper Intake Level (UL) (n = 232). B12 intake was 12.1 μg/day (0.3, 2336); 96% of women met the EAR with 7% exceeding the EAR 100-fold (n = 232). Vitamin D intake was 564 IU/day (0.0, 11 062); 83% met the EAR, whereas 1.7% exceeded the UL (n = 232). Choline intake was 338 mg/day (120, 1016); only 18% met the Adequate Intake and none exceeded the UL (n = 158). Conclusion: To meet the nutrient requirements of pregnancy many women rely on prenatal vitamins. Reformulating prenatal multivitamin supplements to provide doses of vitamins within recommendations to complement a balanced healthy diet would ensure appropriate micronutrient intakes for pregnant women.

Voluntary fortification is ineffective to maintain the vitamin B12 and folate status of older Irish adults: evidence from the Irish Longitudinal Study on Ageing (TILDA)

Mandatory fortification of staple grains with folic acid and/or vitamin B12 (B12) is under debate in many countries including Ireland, which has a liberal, but voluntary, fortification policy. Older adults can be at risk of both deficiency and high folate status, although little is known on the actual prevalence and the major predictors. Population prevalence estimates from older adults (n 5290 ≥50 years) from the Irish Longitudinal Study on Ageing (TILDA) (Wave 1) are presented here. Measures included plasma total vitamin B12 and folate, whereas predictors included detailed demographic, socio-economic, geographic, seasonal and health/lifestyle data. The prevalence of deficient or low B12 status (45 nmol/l) was observed in 8·9 %, whereas high B12 status was observed in 3·1 % (>601 pmol/l). The largest positive predictor of B12 concentration was self-reported B12 injection and/or supplement use (coefficient 51·5 pmol/; 95 % CI 9·4, 93·6; P=0·016) followed by sex and geographic location. The largest negative predictor was metformin use (-33·6; 95 % CI -51·9, -15·4; P<0·0001). The largest positive predictor of folate concentration was folic acid supplement use (6·0; 95 % CI 3·0, 9·0 nmol/l; P<0·001) followed by being female and statin medications. The largest negative predictor was geographic location (-5·7; 95 % CI -6·7, -4·6; P<0·0001) followed by seasonality and smoking. B-vitamin status in older adults is affected by health and lifestyle, medication, sampling period and geographic location. We observed a high prevalence of low B12 and folate status, indicating that the current policy of voluntary fortification is ineffective for older adults.

Joint effects of folate and vitamin B12 imbalance with maternal characteristics on gestational diabetes mellitus

BACKGROUND

This study examined whether folate and vitamin B₁₂ imbalance is associated with gestational diabetes mellitus (GDM) and explored interactions between B vitamin imbalance and maternal risk factors for GDM.

METHODS

A cross-sectional study was performed in 406 Chinese pregnant women. Serum folate, vitamin B₁₂ , and blood glucose concentrations were measured at 24 to 28 weeks gestation during GDM screening. A diagnosis of GDM was made based on International Association of Diabetes and Pregnancy Study Groups criteria (fasting plasma glucose [FPG] ≥5.1 mM, 1-hour plasma glucose ≥10.0 mM, or 2-hour plasma glucose ≥8.5 mM). Binary logistic regression was used to obtain odds ratios (ORs) after controlling for different confounders.

RESULTS

Higher folate levels were associated with higher glucose concentrations and a higher risk of GDM (OR 1.98; 95% confidence interval [CI] 1.00-3.90), whereas higher vitamin B₁₂ levels were associated with lower FPG and a lower risk of GDM (OR 0.30; 95% CI 0.15-0.60). A higher folate: vitamin B₁₂ ratio was associated with higher glucose and a higher risk of GDM (OR 3.08; 95% CI 1.63-5.83). The presence of both a higher folate: vitamin B₁₂ ratio and advanced age further increased the OR to 2.13 (95% CI 1.09-4.15) with a significant additive interaction. Furthermore, a higher folate: vitamin B₁₂ ratio and a higher prepregnancy body mass index (pp-BMI) were synergistically associated with an increased risk of GDM (OR 3.03; 95% CI 1.40-6.57).

CONCLUSIONS

An imbalance between folate and vitamin B₁₂ , represented by a higher folate: vitamin B₁₂ ratio, was highly associated with GDM risk, and this association could be further modified by maternal age and pp-BMI.

Folic acid – role in the body, recommendations and clinical significance

Introduction. Folic acid is a compound classified as B group vitamins. In the body it is subject to processes that transfer its inactive form into a form responsible for biological effects of folic acid, i.e. 5-methyltetrahydrofolate (5-MTHF). It is, in particular, responsible for processes of the correct biosynthesis of purine and pyridine bases present in the formation of DNA and RNA molecules. Humans do not synthesize the endogenous form of folic acid; therefore, it is vital to supplement this vitamin in its natural form or multivitamin preparations. The most folic acid is found in the green leafy vegetables (spinach, peas, asparagus) and in offal (liver). An adequate supply of folic acid is especially indicated in pregnant women with a reduced amount of folic acid due to its use by an intensively developing foetus. The recommended dose of folic acid during this period is 0.4 mg/24h and this dose varies depending on the patient’s and her family’s medical history. The updated state of knowledge on the role of vitamin B9 in the body has been presented. The importance of its supplementation in specific clinical cases was analyzed.

Summary. Many studies indicate an important role of the folic acid in the prevention of congenital defects of the nervous, cardiovascular and urogenital systems. Its deficiency increases the risk of complications in pregnancy, such as recurrent miscarriages, pre-eclampsia or postpartum haemorrhage. For this reason, a prophylactic folic acid supplementation is recommended, in women with increased risk of its deficiency, in particular.

Etiology and clinico-hematological profile of pancytopenia: experience of a Mexican Tertiary Care Center and review of the literature

BACKGROUND

Pancytopenia is a frequent entity in clinical practice as a feature of a myriad of conditions, ranging from benign to malignant diseases. Since the cause of pancytopenia depends on environmental factors, it is important to know the common etiologies of pancytopenia, however, few studies address this.

OBJECTIVES

To identify the etiology of pancytopenia in our population and compare them with what is reported elsewhere.

METHODS

We conducted an observational study of patients with pancytopenia in a Mexican Tertiary Care Center. Clinical, hematological and bone marrow studies were performed in all patients.

RESULTS

Of 109 cases included, the mean age at diagnosis was 49.4 years, with a slightly higher female incidence (53.2%). The most common causes of pancytopenia were: MDS (20.2%), megaloblastic anemia (18.3%) and AML (12.8%).

DISCUSSION

We found a complex picture of pancytopenia in Mexico and compared it with what is reported elsewhere in the literature.

CONCLUSION

The sociocultural context in which the patients develop helps narrowing the possible etiology of pancytopenia, and therefore hasten the diagnostic process. Of all the studies available, bone marrow aspiration seems the most useful.

Excess Folic Acid Supplementation Before and During Pregnancy and Lactation Activates Fos Gene Expression and Alters Behaviors in Male Mouse Offspring

Periconceptional folic acid (FA) supplementation is recommended to prevent neural tube defects and other birth defects. After 20 years mandate food fortification with FA, serum concentration of folate and unmetabolized FA increased significantly in the North American population. But whether excess FA intake impairs neurodevelopment and behavior is still controversial. Here, we treated mice with approximately 2.5-fold (moderate dose of FA, MFA) or 10-fold (high dose of FA, HFA) the dietary requirement of FA 1 week before mating and throughout pregnancy and lactation, and examined behaviors in adult male offspring using open field test, three-chamber sociability and social novelty test, elevated plus maze, rotarod and Morris water maze. We found that early life MFA supplementation increased long-term body weight gain in adults, elevated anxiety-like behavior, and impaired social preference, motor learning and spatial learning ability without modifying motor ability and spatial memory. In contrast, HFA supplementation only induced mild behavioral abnormality. RNA sequencing revealed that FA supplementation altered the expression of brain genes at weaning, among which Fos and related genes were significantly up-regulated in MFA mice compared with control and HFA mice. Quantitative real time-PCR (qRT-PCR) and western blots confirmed the increase of these genes. Our results suggested that FA supplementation during early life stage affected gene expression in weaning mice, and exhibited long-term impairments in adult behaviors in a dose-sensitive manner.

Serum folate and vitamin B12 status in young Brazilian children

OBJECTIVE

To assess the nutritional status of folate and vitamin B12 with anaemia in young children.

DESIGN

A cross-sectional study was conducted at the primary health-care centres of four Brazilian cities. Folate and vitamin B12 were assessed by fluoroimmunoassay. Multilevel Poisson regression models were used to explore the association of folate and vitamin B12 status in relation to anaemia in young children.

SETTING

Brazil.ParticipantsChildren (n 460) aged 11 to 15 months.

RESULTS

The median (interquartile range) of serum folate was 39·7 (28·8-55·3) nmol/l and only four children presented with folate deficiency (&lt;10 nmol/l). Surprisingly, 30·9 % of children presented with serum folate concentrations above the upper limit of detectable values by the commercial kit used for analysis. The frequency of vitamin B12 deficiency (&lt;148 pmol/l) was 15 % and it was inversely associated with the highest tertile of serum folate concentrations (P&lt;0·001). Having high serum folate concentration (≥50·1 nmol/l) and vitamin B12≥148 pmol/l was associated with lower frequency of anaemia in these children (prevalence ratio=0·53; 95% CI 0·30, 0·92).

CONCLUSIONS

High frequency of elevated serum concentration of folate was found among young Brazilian children and 15 % of them had vitamin B12 deficiency. The combination of high serum folate and normal vitamin B12 status was associated with a lower frequency of anaemia in these children. Improvements in the current strategies to promote healthy food-based complementary feeding along with prevention and control of micronutrient deficiencies are recommended to improve children's health.

The Vitamine Source, Usual Food Intake at Students

INTRODUCTION

Inadequate vitamin B 12, folate status and B6 are associated with an increased risk for chronic diseases that may have a negative impact on the health.

AIM

The aim of our study was to investigate dietary intake of vitamin B12, B6 and folates from various foods among the university students.

METHODS

Dietary intake of foods having vitamins B12, B6 and folate was assessed among the students of University of Sarajevo, 19-22 years old, from 2017 to 2018. The participants were interviewed to collect information regarding age, socioeconomic status, B12, folate, B6 vitamin, and usual food intake during one week.

RESULTS

The main sources of vitamin B12 and B6 in the students' diet were chicken white meat (51.8-53.7 %), beef (45-63 %), cream (62.2 -72.1 %), sardines in oil (47.9-52.2 %), tuna (55.2 -60.4 %), cheese edamer (80.1%) and cheese feta (67.4%-73%). The foods with a high source of vitamin B12 and B6 but rarely consumed were fish, shellfish, salmon, roasted trout and mackerel. Sufficient folate intake was mainly achieved through dietary intake of beans (48.5-57.2%) and oatmeal (46.3-48.2%), while folate-insufficient diet resulted from intake of spinach (30.9-35 %), turkey (26.2-33.4 %), lentils (16.9-19.7 %) and soy (9.4-15.5%).

CONCLUSION

Our results show that there is an important percentage of the students in Canton Sarajevo that do not meet the recommended intakes for vitamin B12 and B6 and folate. Additional research is needed to establish the best cost-effective public health approach to achieve sufficient intake of these vitamins.

An appraisal of folates as key factors in cognition and ageing-related diseases

Folic acid (FA) is often consumed as a food supplement and can be found in fortified staple foods in various western countries. Even though FA supplementation during pregnancy is known to prevent severe congenital anomalies in the developing child (e.g., neural tube defects), much less is known about its influence on cognition and neurological functioning. In this review, we address the advances in this field and situate how folate intake during pregnancy, postnatal life, adulthood and in the elderly affects cognition. In addition, an association between folate status and ageing, dementia and other neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis is discussed. While its role in the incidence and severity of these diseases is becoming apparent, the underlying action of folates and related metabolites remains elusive. Finally, the potential of FA as a nutraceutical has been proposed, although the efficacy will highly depend on the interplay with other micronutrients, the disease stage and the duration of supplementation. Hence, the lack of consistent data urges for more animal studies and (pre)clinical trials in humans to ascertain a potential beneficial role for folates in the treatment or amelioration of cognitive decline and ageing-related disorders.

Neuropathology of vitamin B12 deficiency in the Cd320-/- mouse

In humans, vitamin B12 deficiency causes peripheral and CNS manifestations. Loss of myelin in the peripheral nerves and the spinal cord (SC) contributes to peripheral neuropathy and motor deficits. The metabolic basis for the demyelination and brain disorder is unknown. The transcobalamin receptor-knockout mouse ( Cd320-/-) develops cobalamin (Cbl) deficiency in the nervous system, with mild anemia. A decreased S-adenosylmethionine: S-adenosylhomocysteine ratio and increased methionine were seen in the brain with no significant changes in neurotransmitter metabolites. The structural pathology in the SC presented as loss of myelin in the axonal tracts with inflammation. The sciatic nerve (SN) showed increased nonuniform, internodal segments suggesting demyelination, and remyelination in progress. Consistent with these changes, the Cd320-/- mouse showed an increased latency to thermal nociception. Further, lower amplitude of compound action potential in the SN suggested that the functional capacity of the heavily myelinated axons were preferentially compromised, leading to loss of peripheral sensation. Although the metabolic basis for the demyelination and the structural and functional alterations of the nervous system in Cbl deficiency remain unresolved, the Cd320-/- mouse provides a unique model to investigate the pathologic consequences of vitamin B12 deficiency. -Arora, K., Sequeira, J. M., Alarcon, J. M., Wasek, B., Arning, E., Bottiglieri, T., Quadros, E. V. Neuropathology of vitamin B12 deficiency in the Cd320-/- mouse.