Excess Folic Acid Research Articles

Supplementation practices among pregnant women and those trying to conceive: a population-representative survey in Vancouver, Canada.

Dietary supplements including vitamins, minerals, and natural health products are commonly consumed by those aiming to optimize fertility and pregnancy outcomes. The aim of this survey was to describe supplementation practices among individuals who were pregnant or trying to conceive in Vancouver, Canada. An online survey was conducted among 500 individuals who were pregnant (n=250) or trying to conceive (n=250). Participants met a substantial proportion of vitamin and mineral recommendations through supplements alone. Exceptions included calcium, magnesium, and choline, with median (interquartile range (IQR)) supplementation doses reported by those who were pregnant and trying to conceive, respectively, of: 250 (200 and 250mg) and 250 (200 and 250mg), 50 (50 and 75mg) and 50 (50 and 90mg), and 53 (10 and 150mg) and 55 (10 and 100mg), as compared to perinatal recommendations of 1000mg/day (calcium), 350mg/day (magnesium), and 450mg/day (choline). Conversely, median (IQR) doses of folate reported by those who were pregnant and trying to conceive, respectively, were: 1000 (780 and 1000µg) and 1000 (800 and 1000µg), with ∼70% overall (337/471) reporting doses ≥1000µg (the tolerable upper intake level). Most participants (451/500; 90%) reported supplementation with a prenatal multivitamin; of these, 83% reported that supplementation occurred daily. Overall, as diet was not considered, we cannot ascertain whether recommendations for calcium, magnesium, and choline were met through the combination of supplements and foods; however, we believe that additional supplementation with choline may be required to meet recommendations in pregnancy. Excessive folate supplementation has been previously identified as a concern throughout North America; here, we provide further evidence for excessively high doses consumed via supplements.

Excess Folic Acid Exposure Increases Uracil Misincorporation into DNA in a Tissue-Specific Manner in a Mouse Model of Reduced Methionine Synthase Expression

BackgroundFolate and vitamin B12 (B12) are cofactors in folate-mediated 1-carbon metabolism (FOCM), a metabolic network that supports synthesis of nucleotides (including thymidylate [dTMP]) and methionine. FOCM impairments such as a deficiency or imbalance of cofactors can perturb dTMP synthesis, causing uracil misincorporation into DNA. ObjectiveThe purpose of this study was to determine how reduced expression of the B12-dependent enzyme methionine synthase (MTR) and excess dietary folic acid interact to affect folate distribution and markers of genome stability in mouse tissues. MethodsHeterozygous Mtr knockout mice (Mtr+/–) model the FOCM-specific effects of B12 deficiency. Folate accumulation and vitamer distribution, genomic uracil concentrations, and phosphorylated histone H2AX (γH2AX) immunostaining were measured in male Mtr+/+ and Mtr+/− mice weaned to either a folate-sufficient control (C) diet (2 mg/kg folic acid) or a high folic acid (HFA) diet (20 mg/kg folic acid) for 7 wk. ResultsExposure to the HFA diet led to tissue-specific patterns of folate accumulation, with plasma, colon, kidney, and skeletal muscle exhibiting increased folate concentrations compared with control. Liver total folate did not differ. Although unmetabolized folic acid (UMFA) increased 10-fold in mouse plasma with HFA diet, UMFA accounted for <0.2% of total folate in liver and colon tissue. Exposure to HFA diet resulted in a shift in folate distribution in colon tissue with higher 5-methyl-THF and lower formyl-THF than in control mice. Mtr heterozygosity did not impact folate accumulation or distribution in any tissue. Mice on HFA diet exhibited higher uracil in genomic DNA and γH2AX foci in colon. Similar differences were not seen in liver. ConclusionsThis study demonstrates that folic acid, even when consumed at high doses, does not meaningfully accumulate in mouse tissues, although high-dose folic acid shifts folate distribution and increases uracil accumulation in genomic DNA in colon tissue.

Excess folic acid mimics deficiency in human placenta in vitro

Excess folic acid mimics deficiency in human placenta in vitro

Integrating fruit by-products and whey for the design of folate-bioenriched innovative fermented beverages safe for human consumption

Global concerns over folate deficiency, the risks of excessive synthetic folic acid consumption, and food loss implications for environmental sustainability and food security drive needs of innovative approaches that align food by-product valorisation with folate bio-enrichment. This study explored the use of three fruit by-products extracts (grape, passion fruit, and pitaya) and whey to develop a folate bio-enriched fermented whey-based beverage. Three strains (Lacticaseibacillus rhamnosus LGG, Bifidobacterium infantis BB-02, and Streptococcus thermophilus TH-4) were tested for folate production in different fermentation conditions in modified MRS medium and in a whey-based matrix prepared with water extracts of these fruit by-products. B. infantis BB-02 and S. thermophilus TH-4, alone and in co-culture, were the best folate producers. The selection of cultivation conditions, including the presence of different substrates and pH, with grape by-product water extract demonstrating the most substantial effect on folate production among the tested extracts, was crucial for successfully producing a biofortified fermented whey-based beverage (FWBB). The resulting FWBB provided 40.7 μg of folate per 100 mL after 24 h of fermentation at 37 °C, effectively leveraging food by-products. Moreover, the beverage showed no cytotoxicity in mouse fibroblast cells tests. This study highlights the potential for valorising fruit by-products and whey for the design of novel bioenriched foods, promoting health benefits and contributing to reduced environmental impact from improper disposal.

Spatial Transcriptomics and Single-Nucleus Multi-omics Analysis Revealing the Impact of High Maternal Folic Acid Supplementation on Offspring Brain Development.

Folate, an essential vitamin B9, is crucial for diverse biological processes including neurogenesis. Folic acid (FA) supplementation during pregnancy is a standard practice for preventing neural tube defects (NTDs). However, concerns are growing over the potential risks of excessive maternal FA intake. Here, we employed mouse model and spatial transcriptomics and single-nucleus multi-omics approaches to investigate the impact of high maternal FA supplementation during the periconceptional period on offspring brain development. Maternal high FA supplementation affected gene pathways linked to neurogenesis and neuronal axon myelination across multiple brain regions, as well as gene expression alterations related to learning and memory in thalamic and ventricular regions. Single-nucleus multi-omics analysis revealed that maturing excitatory neurons in the dentate gyrus (DG) are particularly vulnerable to high maternal FA intake, leading to aberrant gene expressions and chromatin accessibility in pathways governing ribosomal biogenesis critical for synaptic formation. Our findings provide new insights into specific brain regions, cell types, gene expressions and pathways that can be affected by maternal high FA supplementation.

Managing Normal Tension Glaucoma with Dietary Folate

Normal-Tension Glaucoma (NTG) is the most prevalent form of glaucoma among individuals in Asian countries. While lowering intraocular pressure (IOP) remains the standard of care, this approach is insufficient for most NTG patients. Recent evidence documents the role of ischemia and oxidative stress as critical factors affecting the optic nerve in NTG. Consequently, addressing these factors has been recommended as a neuroprotective strategy. While conventional treatment strategies primarily target the reduction of IOP, this yields limited efficacy and eventual blindness in many NTG cases. Recent studies document another crucial parameter: Retinal Venous Pressure (RVP). Elevated RVP impedes retinal perfusion, resulting in oxidative stress and localized ischemia, and exacerbating optic nerve damage in NTG. Elevated RVP also appears to be a contributing factor in small vessel ischemia associated with diabetic retinopathy and macular degeneration. The underlying cause of elevated RVP is small vessel endotheliopathy, which may result from alterations in methylation and B-vitamin metabolism, leading to changed microcirculation. This metabolic disruption can arise from dietary inadequacies, malabsorption, or genetic polymorphisms affecting the methylation pathways. Restoring plasma levels of folate and B-12 can be achieved through supplementation with natural forms of these vitamins, specifically L-methylfolate, and methylcobalamin. Unlike oxidized folate (folic acid), which must be enzymatically converted to methylfolate to penetrate the blood-retinal barrier, L-methylfolate can be directly utilized. Excess unmetabolized folic acid can impede methyl folate absorption into the retina, underscoring the necessity of using methyl folate for effective supplementation. We propose integrating RVP screening into NTG risk assessments and consider a targeted vitamin supplement, such as Ocufolin®, as a viable adjunct approach to manage elevated RVP and potentially mitigate NTG progression.

Epigenetic regulation by TET1 in gene-environmental interactions influencing susceptibility to congenital malformations.

The etiology of neural tube defects (NTDs) involves complex gene-environmental interactions. Folic acid (FA) prevents NTDs, but the mechanisms remain poorly understood and at least 30% of human NTDs resist the beneficial effects of FA supplementation. Here, we identify the DNA demethylase TET1 as a nexus of folate-dependent one-carbon metabolism and genetic risk factors post-neural tube closure. We determine that cranial NTDs in Tet1 -/- embryos occur at two to three times higher penetrance in genetically heterogeneous than in homogeneous genetic backgrounds, suggesting a strong impact of genetic modifiers on phenotypic expression. Quantitative trait locus mapping identified a strong NTD risk locus in the 129S6 strain, which harbors missense and modifier variants at genes implicated in intracellular endocytic trafficking and developmental signaling. NTDs across Tet1 -/- strains are resistant to FA supplementation. However, both excess and depleted maternal FA diets modify the impact of Tet1 loss on offspring DNA methylation primarily at neurodevelopmental loci. FA deficiency reveals susceptibility to NTD and other structural brain defects due to haploinsufficiency of Tet1. In contrast, excess FA in Tet1 -/- embryos drives promoter DNA hypermethylation and reduced expression of multiple membrane solute transporters, including a FA transporter, accompanied by loss of phospholipid metabolites. Overall, our study unravels interactions between modified maternal FA status, Tet1 gene dosage and genetic backgrounds that impact neurotransmitter functions, cellular methylation and individual susceptibilities to congenital malformations, further implicating that epigenetic dysregulation may underlie NTDs resistant to FA supplementation.

Nanopore sequencing demonstrates the roles of spermatozoal DNA N6-methyladenine in mediating transgenerational lipid metabolism disorder induced by excessive folate consumpton

Increased consumption of folic acid is prevalent due to its beneficial effects, but growing evidence emphasizes the side effects pointing to excessive dietary folate intake. The effects of excessive paternal folic acid consumption on offspring and its transgenerational inheritance mechanism have not been elucidated. We hypothesize that excessive folic acid consumption will alter sperm DNA N6-methyladenine (6mA) and 5-methylcytosine (5mC) methylation and heritably influence offspring metabolic homeostasis. Here, we fed roosters either folic acid-control or folic acid-excess diet throughout life. Paternal chronic folic acid excessive supplementation increased hepatic lipogenesis and lipid accumulation but reduced lipolysis both in the roosters and their offspring, which was further confirmed to be induced by one-carbon metabolism inhibition and gene expression alteration associated with the Peroxisome proliferator-activated receptor pathway. Based on the spermatozoal genome-wide DNA methylome identified by Nanopore sequencing, multi-omics association analysis of spermatozoal and hepatic DNA methylome, transcriptome, and metabolome suggested that differential spermatozoal DNA 6mA and 5mC methylation could be involved in regulating lipid metabolism-related gene expression in offspring chickens. This model suggests that sperm DNA N6-methyladenine and 5-methylcytosine methylation were involved in epigenetic transmission and that paternal dietary excess folic acid leads to hepatic lipid accumulation in offspring.

Excess Folic Acid and Vitamin B12 Deficiency: Clinical Implications?

In the 1940s to 1950s, high-dose folic acid supplements (>5 mg/d) were used clinically to reverse the megaloblastic anemia of vitamin B12 deficiency caused by pernicious anemia. However, this treatment strategy masked the underlying B12 deficiency and possibly exacerbated its neuropathological progression. The issue of masking and exacerbating B12 deficiency has recently been rekindled with the institution of folic acid fortification and the wide-spread use of folic acid supplements. The objectives of this review are to describe clinical and epidemiological evidence that excess folic acid exacerbates B12 deficiency, to summarize a hypothesis to explain this phenomenon, and to provide guidance for clinicians. Cognitive function test scores are lower and blood homocysteine and methylmalonic acid concentrations are higher in people with low B12 and elevated folate than in those with low B12 and nonelevated folate. High-dose folic acid supplementation in patients with pernicious anemia or epilepsy cause significant reductions in serum B12. It is hypothesized that high-dose folic acid supplements cause depletion of serum holotranscobalamin and thus exacerbate B12 deficiency. The evidence for excess folic acid exacerbating B12 deficiency is primarily correlative or from uncontrolled clinical observations, and the hypothesis to explain the phenomenon has not yet been tested. Nonetheless, the evidence is sufficiently compelling to warrant increased vigilance for identifying B12 deficiency in at risk individuals, including older adults and others with low B12 intake or conditions that are associated with B12 malabsorption, who also ingest excessive folic acid or are prescribed folic acid in high doses.

Maternal serum unmetabolized folic acid concentration following multivitamin and mineral supplementation with or without folic acid after 12 weeks gestation: A randomized controlled trial.

Pregnant women are advised to take folic acid (FA) supplements before conception and during the first trimester of pregnancy. Many women continue FA supplementation throughout pregnancy, and concerns have been raised about associations between excessive FA intake and adverse maternal and child health outcomes. Unmetabolized folic acid (UMFA) is found in serum after high FA intakes and is proposed as a biomarker for excessive FA intake. We aimed to determine if removing FA from prenatal micronutrient supplements after 12 weeks of pregnancy reduces serum UMFA concentrations at 36 weeks gestation. In this double-blind, randomized controlled trial conducted in South Australia, 103 women with a singleton pregnancy were randomly assigned at 12-16 weeks gestation to take a micronutrient supplement containing noFA or 800 µg/day FA from enrollment until 36 weeks gestation. Ninety women (0 µg/day FA n = 46; 800 µg/day FA n = 44) completed the study. Mean, UMFA concentration was lower in the women randomized to the 0 µg/day group compared to the 800 µg/day FA group, 0.6 ± 0.7 and 1.4 ± 2.7 nmol/L, respectively. The adjusted mean difference (95% CI) in UMFA between the groups was [-0.85 (-1.62, -0.08) nmol/L, p = 0.03]. Maternal serum and red blood cell folate concentrations were lower in the 0 µg/day FA group than in the 800 µg/day group (median 23.2 vs. 49.3 and1335 vs. 1914 nmol/L, respectively; p < 0.001). Removing FA at 12-16 weeks gestation from prenatal micronutrient supplements reduced the concentration of UMFA at 36 weeks gestation.

Impact of varying maternal dietary folate intake on cerebellar cortex histomorphology and cell density in offspring rats.

The cerebellum has a long, protracted developmental period that spans from the embryonic to postnatal periods; as a result, it is more sensitive to intrauterine and postnatal insults like nutritional deficiencies. Folate is crucial for foetal and early postnatal brain development; however, its effects on cerebellar growth and development are unknown. The aim of this study was to examine the effects of maternal folate intake on the histomorphology and cell density of the developing cerebellum. Twelve adult female rats (rattus norvegicus) were randomly assigned to one of four premixed diet groups: standard (2mg/kg), folate-deficient (0mg/kg), folate-supplemented (8mg/kg) or folate supra-supplemented (40 mg/kg). The rats started their diets 14 days before mating and consumed them throughout pregnancy and lactation. On postnatal days 1, 7, 21 and 35, five pups from each group were sacrificed, and their brains were processed for light microscopic analysis. Histomorphology and cell density of the external granule, molecular, Purkinje and internal granule layers were obtained. The folate-deficient diet group had smaller, dysmorphic cells and significantly lower densities of external granule, molecular, Purkinje and internal granule cells. Although the folate-enriched groups had greater cell densities than the controls, the folate-supplemented group had considerably higher cell densities than the supra-supplemented group. The folate supra-supplemented group had ectopic Purkinje cells in the internal granule cell layer. These findings imply that a folate-deficient diet impairs cellular growth and reduces cell density in the cerebellar cortex. On the other hand, folate supplementation increases cell densities, but there appears to be an optimal dose of supplementation since excessive folate levels may be detrimental.

DTYMK is an essential gene in mice and heterozygosity does not cause neural tube defects

Regulation of nucleotide biosynthesis is necessary for maintaining cellular processes including DNA replication and repair. A key enzyme in this process is deoxythymidylate kinase (dTYMK), which catalyzes the initial step in the production of dTTP from dTMP. This gene constitutes the first merged step of dTTP synthesis from the de novo and salvage pathways which regulate dTMP biosynthesis. Decreased de novo dTMP biosynthesis causes dysregulated dTTP:dUTP pools, and leads to increased uracil in DNA and neural tube closure defect (NTD) development in mice. The goal of this research was to investigate if dTYMK, the downstream enzyme in dTTP production, is an essential gene in mice and if impairments in dTYMK play a causal role in development including NTD pathology in mice. Dtymk+/− C57BL/6J females were weaned onto either a control, excess folic acid, or folic acid deficient diet and timed breeding was performed after 8 weeks on diet. The offspring were analyzed for NTDs and other reproductive outcomes at embryonic day 12.5 (E12.5). Dtymk–/– mice were confirmed to be embryonic lethal before E12.5, and Dtymk+/− mice on all three experimental diets did not show the presence of open neural tube defects, spina bifida or exencephaly. However, the expression of dTYMK in Dtymk+/− mouse embryos was confirmed to be decreased by approximately 3-fold compared to Dtymk+/+ embryos. Although dTYMK was demonstrated to be an essential gene in mice and is required for the regulation of nucleotide pools in vitro, there was no evidence of increased risk of NTDs because of a reduction in expression of this enzyme during embryonic development. It is possible that a further reduction in expression may be required to see developmental anomalies in C57BL/6J mice.

Folate-mediated Transport of Nanoparticles across the Placenta.

In this study, a prototype of a targeted nanocarrier for drug delivery for prenatal therapy of the developing fetus was developed and examined in vitro and ex vivo. The folate transport mechanism in the human placenta was utilized as a possible pathway for the transplacental delivery of targeted nanoparticles. Several types of folic acid-decorated polymeric nanoparticles were synthesized and characterized. During transport studies of targeted and non-targeted fluorescent nanoparticles across the placental barrier, the apparent permeability values, uptake, transfer indices, and distribution in placental tissue were determined. The nanoparticles had no effect on BeWo b30 cell viability. In vitro, studies showed significantly higher apparent permeability of the targeted nanoparticles across the cell monolayers as compared to the nontargeted nanoparticles (Pe = 5.92 ± 1.44 ×10-6 cm/s for PLGA-PEG-FA vs. 1.26 ± 0.31 ×10-6 cm/s for PLGA-PEG, P < 0.05), and the transport of the targeted nanoparticles was significantly inhibited by excess folate. Ex vivo placental perfusion showed significantly greater accumulation of the targeted nanoparticles in the placental tissue (4.31 ± 0.91%/g for PLGA-PEG-FA vs. 2.07 ± 0.26%/g for PLGA-PEG). The data obtained suggested different mechanisms for the uptake and transplacental transfer of targeted versus nontargeted nanoparticles. This targeted nanoformulation may be a promising strategy for fetal drug therapy.

Risk of Excess Maternal Folic Acid Supplementation in Offspring.

Folate, also known as vitamin B9, facilitates the transfer of methyl groups among molecules, which is crucial for amino acid metabolism and nucleotide synthesis. Adequate maternal folate supplementation has been widely acknowledged for its pivotal role in promoting cell proliferation and preventing neural tube defects. However, in the post-fortification era, there has been a rising concern regarding an excess maternal intake of folic acid (FA), the synthetic form of folate. In this review, we focused on recent advancements in understanding the influence of excess maternal FA intake on offspring. For human studies, we summarized findings from clinical trials investigating the effects of periconceptional FA intake on neurodevelopment and molecular-level changes in offspring. For studies using mouse models, we compiled the impact of high maternal FA supplementation on gene expression and behavioral changes in offspring. In summary, excessive maternal folate intake could potentially have adverse effects on offspring. Overall, we highlighted concerns regarding elevated maternal folate status in the population, providing a comprehensive perspective on the potential adverse effects of excessive maternal FA supplementation on offspring.

The gut microbiome regulates the clinical efficacy of sulfasalazine therapy for IBD-associated spondyloarthritis

Sulfasalazine is a prodrug known to be effective for the treatment of inflammatory bowel disease (IBD)-associated peripheral spondyloarthritis (pSpA), but the mechanistic role for the gut microbiome in regulating its clinical efficacy is not well understood. Here, treatment of 22 IBD-pSpA subjects with sulfasalazine identifies clinical responders with a gut microbiome enriched in Faecalibacterium prausnitzii and the capacity for butyrate production. Sulfapyridine promotes butyrate production and transcription of the butyrate synthesis gene but in F. prausnitzii invitro, which is suppressed by excess folate. Sulfasalazine therapy enhances fecal butyrateproduction and limits colitis in wild-type and gnotobiotic mice colonized with responder, but not non-responder, microbiomes. F. prausnitzii is sufficient to restore sulfasalazine protection from colitis in gnotobiotic mice colonized with non-responder microbiomes. These findings reveal a mechanistic link between the efficacy of sulfasalazine therapy and the gut microbiome with the potential to guide diagnostic and therapeutic approaches for IBD-pSpA.

Association of serum folic acid levels in response to fasting blood glucose in early pregnancy with the risk of gestational diabetes mellitus: A retrospective cohort study

ObjectiveWith increasingly prevalent folic acid consumption in early pregnancy, concerns about its potentially negative effect on maternal metabolism have been raised. Recent findings regarding folic acid levels in the first trimester and the risk of gestational diabetes mellitus have been inconclusive. The aim of this study was to investigate the association of folic acid status in early pregnancy with gestational diabetes mellitus as well as examine whether glucose levels can be modulated by folic acid status during the same first trimester. MethodsThis was a retrospective cohort study based on 27 128 Chinese pregnant women who registered during their first prenatal visit from January 2015 to December 2019. Serum folic acid and fasting blood glucose concentrations were measured during the 9th to 13th gestational weeks. Binary logistic regression was applied to estimate the odds ratios of gestational diabetes mellitus by using the serum folic acid levels quartiles with adjustment for major confounders. To investigate the potential effect of modifying key risk factors for gestational diabetes mellitus, we established subgroups, in which analyses were stratified by age (<25, 25–29, 30–34, and ≥35 y), parity (nulliparous and parous), prepregnancy body mass index (< 18.5, 18.5–23.9, and ≥ 24 kg/m2), and family history of diabetes (yes and no). ResultsThe positive association between maternal folate concentrations and fasting blood glucose was observed: the risk for hyperglycemia was higher in those in the middle (Q3) and higher (Q4) quartiles compared with those in Q1 and Q2. A higher risk for gestational diabetes mellitus was found in hyperglycemia of early pregnant women with high folate concentrations (Q3: odds ratio = 5.63; 95% CI, 4.56–6.95, and Q4: odds ratio = 5.57; 95% CI, 4.68–6.64) compared with normal fasting glucose mothers with folate concentrations in Q1 and Q2 after accounting for multiple covariables. Similar patterns were observed for different subgroups. Restricted cubic spline plots had a positive correlation of serum folic acid level with fasting blood glucose concentration as well as risk of gestational diabetes mellitus in a nonlinear pattern, with 32.5 nmol/L as the cutoff point for folic acid level. ConclusionsOur findings underscore the importance of maintaining an appropriate folic acid concentration for preserving a lower risk of gestational diabetes mellitus, especially in women with relatively higher blood glucose in early pregnancy. Additionally, folic acid concentration > 32.5 nmol/L may be considered a risk factor for gestational diabetes mellitus. This research suggested that folic acid levels should be monitored during the first trimester from the first prenatal checkup to prevent adverse effects of excessive folic acid intake.

Relationship of dietary natural folate and synthetic folic acid co-exposure patterns with biological aging: findings from NHANES 2003-2018.

Background: The mandatory folic acid fortification program in the United States has inevitably exposed most Americans to both natural folate and synthetic folic acid. We aim to examine the association of dietary folate co-exposure patterns with biological aging indicators. Methods: A total of 18 889 participants were enrolled from 2003 to 2018. Dietary intake of folate from diverse sources was evaluated by 24-hour dietary recall. Biological aging indicators were developed based on age-related clinical indicators, including the phenotypic age (PA), Klemera-Doubal method (KDM), homeostatic dysregulation (HD), and allostatic load (AL). The unsupervised K-means clustering method, logistic regression model, and restricted cubic spline (RCS) regression model were used to explore the relationship of natural folate and synthetic folic acid co-exposure with biological aging indicators. Results: The results indicated that higher intake of total folate, dietary folate, and food natural folate was associated with lower PA [OR = 0.75 (0.64, 0.88); OR = 0.79 (0.70, 0.90); OR = 0.65 (0.57, 0.75)], KDM [OR = 0.63 (0.53, 0.75); OR = 0.80 (0.65, 0.98); OR = 0.62 (0.49, 0.77)], HD [OR = 0.69 (0.56, 0.84); OR = 0.78 (0.67, 0.92); OR = 0.78 (0.68, 0.90)], and AL [OR = 0.69 (0.58, 0.82); OR = 0.73 (0.63, 0.85); OR = 0.74 (0.62, 0.90)], consistently. Four co-exposure patterns were generated based on the intake of folate from diverse sources, as follows: "low folate exposure group" to cluster 1, "dietary folate exposure group" to cluster 2, "mixed source high folate exposure group" to cluster 3, and "mixed source excessive folate exposure group" to cluster 4. Compared with cluster 1, participants in cluster 2 are associated with lower biological age indicators (ORPA = 0.82 [0.72, 0.93]; ORKDM = 0.58 [0.47, 0.70]; ORHD = 0.85 [0.75, 0.97]; ORAL = 0.87 [0.77, 0.98]), while participants in cluster 3 and cluster 4 are not. Conclusion: For individuals subjected to folic acid fortification programs, a higher intake of dietary folate, especially natural folate, coupled with a lower consumption of folic acid supplements, was found to be associated with lower biological age indicators.

Fructooligosaccharide feeding during gestation to pregnant mice provided excessive folic acid decreases maternal and female fetal oxidative stress by increasing intestinal microbe-derived hydrogen gas

Fructooligosaccharide (FOS) is fermented by intestinal microbes to generate intestinal microbe-derived hydrogen gas (IMDH). Oxidative stress increases during gestation, whereas hydrogen gas has antioxidant effects with therapeutic benefits. We have previously reported that the offspring from a pregnant, excessive folic acid mouse model (PEFAM) had abnormal glucose metabolism after growth. We hypothesized that IMDH by FOS feeding during gestation in PEFAM would suppress maternal and fetal oxidative stress. C57BL/6J mice on day 1 of gestation were divided into 3 groups and dissected at gestational day 18. The control (CONT) diet was AIN-93G containing folic acid 2 mg/kg diet; PEFAM was fed with an excessive folic acid (EFA) diet containing folic acid 40 mg/kg diet, and the EFA-FOS diet was replaced half of the sucrose in the EFA diet. Hydrogen gas concentrations in maternal livers and whole fetuses in EFA-FOS were significantly higher than those in CONT and EFA, respectively (P < .05). Maternal and fetal 8-hydroxy-2′-deoxyguanosine in EFA-FOS were not significantly different from those in the CONT group, whereas those in the EFA group were significantly increased compared with CONT and EFA-FOS (P < .05). In EFA-FOS, expression of protein and mRNA of superoxide dismutase and heme oxygenase 1 in mothers and superoxide dismutase in fetuses were not significantly different from those in CONT, whereas those in EFA were significantly increased (P < .05). The protein expression of Nrf2 in mothers and fetuses were not significantly different between EFA-FOS and CONT. Therefore, FOS feeding to PEFAM during gestation decreases maternal and fetal oxidative stress through IMDH.

Prenatal folic acid and vitamin B12 imbalance alter neuronal morphology and synaptic density in the mouse neocortex

Previous reports have provided evidence that insufficient or excessive maternal folic acid (FA) intake during pregnancy can alter neurodevelopment of the offspring by modulating prenatal neurogenesis. Furthermore, our earlier work in a mouse model confirmed long-term structural changes at the cellular level of either deficient or excessive FA supply by comparably reducing dendritic arborization of cortical projection neurons. Here, we report that excessive amounts of FA decrease arborization of deep layer projection neurons, but not upper layer neurons and that reduced complexity of deep layer neurons is not observed when folic acid is replaced by folinic acid, a stable reduced form of folate. In addition, deficiency of B12, a vitamin that critically regulates folate metabolism, causes even more marked decreases in neuronal arborization in both deep and upper layer neurons and particularly in combination with FA excess. Furthermore, both FA excess and B12 deficiency affect synaptic density and morphology. Our findings point to neurodevelopmental risks associated with insufficient amounts of prenatal B12, particularly in association with high levels of FA intake, suggesting that the neurodevelopmental program is sensitive to an imbalance in the status of these interacting micronutrients.

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.