Folate, homocysteine and the ovarian cycle among healthy regularly menstruating women

Impact of Prevalent Dietary Pattern on Serum Vitamin B12 Status and Its Association With Inflammation Among Reproductive Age Women

SCOPE

Association between vitamin B12 deficiency (VB12D) and dietary patterns being well documented has bearing on obstetrics and neonatal outcomes. However, relationship between VB12D and serum inflammatory markers (IMs), particularly in vegetarian diet and Polycystic ovary syndrome (PCOS), remains elusive. This cross-sectional study assesses VB12D and IMs among reproductive age women consuming different diets.

METHODS AND RESULTS

Nonvegetarian (PCOS, n = 104; healthy, n = 148) and vegetarian women (PCOS n = 112; healthy, n = 186) are for evaluated clinical, biochemical, hormonal assessment, inflammatory, and four vitamin B 12 (VB12) markers. VB12D is defined by Fedosov's wellness quotient (4cB12). Using 4cB12, prevalence of VB12D is discerned in 54.4% (PCOS: 72.1%; healthy 36.5%) and 93.4% (PCOS: 95.9%; healthy: 91.9%) among nonvegetarians and vegetarians, respectively. Vegetarian PCOS women depict lowest median (interquartile range [IQR]) of serum B12 76.2(72.6) pg mL-1, holotranscobalamine (HTC) 37.9(11.3) and highest homocysteine (HCY) 40.32(6.0) µmol L-1, methylmalonic acid (MMA) 352.26(156.7) nmol L-1 with highest Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and IMs (Monocyte chemoattractant protein 1 (MCP-1), High sensitivity C-reactive protein (hs-CRP), Tumour Necrosis Factor alpha (TNF-α) and Interleukin 6 (IL-6)). Significant correlation of serum hs-CRP, TNF-α, and IL-6 with VB12 markers is observed.

CONCLUSION

The VB12D is rampant among reproductive age women that gets exacerbated by PCOS or vegetarian diet. It is directly correlated with magnitude of proinflammatory markers. The results carry substantial implications for public health policies aimed at improving preconception maternal VB12 status for better future pregnancy and offspring outcomes.

The Role of One-Carbon Metabolism and Methyl Donors in Medically Assisted Reproduction: A Narrative Review of the Literature

One-carbon (1-C) metabolic deficiency impairs homeostasis, driving disease development, including infertility. It is of importance to summarize the current evidence regarding the clinical utility of 1-C metabolism-related biomolecules and methyl donors, namely, folate, betaine, choline, vitamin B12, homocysteine (Hcy), and zinc, as potential biomarkers, dietary supplements, and culture media supplements in the context of medically assisted reproduction (MAR). A narrative review of the literature was conducted in the PubMed/Medline database. Diet, ageing, and the endocrine milieu of individuals affect both 1-C metabolism and fertility status. In vitro fertilization (IVF) techniques, and culture conditions in particular, have a direct impact on 1-C metabolic activity in gametes and embryos. Critical analysis indicated that zinc supplementation in cryopreservation media may be a promising approach to reducing oxidative damage, while female serum homocysteine levels may be employed as a possible biomarker for predicting IVF outcomes. Nonetheless, the level of evidence is low, and future studies are needed to verify these data. One-carbon metabolism-related processes, including redox defense and epigenetic regulation, may be compromised in IVF-derived embryos. The study of 1-C metabolism may lead the way towards improving MAR efficiency and safety and ensuring the lifelong health of MAR infants.

Plasma homocysteine level, estradiol level, and brain atrophy: a Mendelian randomization study

OBJECTIVES

Observational studies link elevated plasma homocysteine (Hcy) with vascular disease. Our aim was to assess the gender difference in the association between the plasma tHcy level and brain atrophy and identify the possible influencer. We employed Mendelian randomization (MR) to explore the causal relationship between plasma tHcy level, estradiol level, and brain atrophy.

METHODS

A total of 687 patients with brain atrophy were included, and gender-specific subgroup analyses in association between tHcy and brain atrophy are conducted. From genome-wide association studies, we selected genetic variants (P < 5 × 10-8) for the plasma tHcy level and estradiol level. We investigated the degree of brain atrophy (including gray matter volume and total brain volume) in the UK biobank (n = 7,916). The inverse variance-weighted and several sensitivity MR regression analyses were carried out.

RESULTS

The plasma tHcy level was significantly associated with brain atrophy for females, but not for males. An MR study showed that there was little evidence of the causal link between elevated plasma tHcy and brain atrophy. On the other hand, we found evidence to support causality for genetically decreased estradiol with higher risk of brain atrophy. Furthermore, genetic predisposition to elevated plasma tHcy was associated with a lower estradiol level.

CONCLUSIONS

The influence of estradiol on the association between tHcy and brain atrophy deserves further investigation.

Management of a Patient With Premenstrual Syndrome Using Acupuncture, Supplements, and Meditation: A Case Report

Objective

The purpose of this case report was to describe a multimodal approach for the treatment of premenstrual syndrome (PMS).

Clinical Features

A 36-year-old nulliparous woman presented to a free clinic for veterans and their spouses. She received a PMS diagnosis at age 18. She was previously prescribed hormonal birth control and nonsteroidal anti-inflammatory drugs, which minimally affected her condition. She stopped using conventional medicine therapies at age 27. Laboratory results showed that her progesterone was below 0.5 ng/mL. Her symptom score was 50 out of 60 on the Treatment Strategies for PMS assessment tool. During her menses, she experienced low back pain and stiffness, bloating, swelling, weight gain, breast tenderness, swelling, and pain, and she felt overwhelmed and stressed.

Intervention and Outcome

Traditional Chinese medicine acupuncture was administered in conjunction with 100 mg of coenzyme Q10 (ubiquinol) and a B-100 complex once a day and 400 mg of magnesium citrate, 1000 mg of flaxseed oil (Linum usitatissimum), and 1000 mg of turmeric (Curcuma longa) twice a day. Five days before the onset of her menstrual period, she was to ingest a B-100 complex twice a day and 400 mg of magnesium citrate, 1000 mg of flaxseed oil, and 1000 mg of turmeric 3 times a day. Mindfulness meditation was encouraged twice a day for 10 minutes to reduce stress. After 12 treatments over 3 months, her symptom score decreased to 18 out of 60 and remained below 20 for an additional 32 weeks.

Conclusion

This patient with PMS symptoms positively responded to a multimodal approach using traditional Chinese medicine-style acupuncture, dietary supplements, and mindfulness meditation.

Variability in Sleep Duration and Biomarkers of Cardiovascular Disease Across the Menstrual Cycle

Variability in sleep duration and cardiovascular health have been infrequently investigated, particularly among reproductive-age women. We examined these associations across the menstrual cycle among a cohort of 250 healthy premenopausal women, aged 18-44 years. The BioCycle study (New York, 2005-2007) collected cardiovascular biomarkers (serum high- and low-density lipoprotein (HDL, LDL), total cholesterol, triglycerides, and C-reactive protein (CRP)) at key time points along the menstrual cycle (follicular, ovulatory, and luteal phases). Women also recorded sleep duration in daily diaries. From these data, we computed L-moments, robust versions of location, dispersion, skewness, and kurtosis. We fitted linear mixed models with random intercepts and inverse probability weighting to estimate associations between sleep variability and cardiovascular biomarkers, accounting for demographic, lifestyle, health, and reproductive factors. Sleep dispersion (any deviation from mean duration) was associated with lower mean LDL for nonshift workers and non-White women. Skewed sleep duration was associated with higher mean CRP and lower mean total cholesterol. Sleep durations with extreme short and long bouts (kurtosis) were associated with a lower mean HDL, but not mean CRP, LDL, or triglycerides. Sleep duration modified associations between sleep dispersion and LDL, HDL, and total cholesterol. Even in young and healthy women, sleep duration variability could influence cardiovascular health.

The Influence of Diet on Ovulation Disorders in Women—A Narrative Review

Female infertility is commonly due to ovulation disorders. They are mostly related to polycystic ovary syndrome, which is currently viewed as one of the most common endocrine disorders in women of reproductive age. Ovulation-related female fertility is influenced by multiple factors which may include: age, smoking cigarettes, stress, use of psychoactive substances, and physical activity. Moreover, diet-related factors play an important role in the regulation of ovulation. Dietary components that exert a positive influence on ovulation include: carbohydrate products with low glycemic index, plant protein, monounsaturated and polyunsaturated fatty acids, folic acid, vitamin D, antioxidants, and iron. A diet based on the structure of the Mediterranean diet also seems beneficial. Components that have a negative influence mostly include high glycemic index carbohydrates, large amounts of animal protein, saturated fatty acids, and trans fatty acids, which are typically found in the Western model of nutrition. Due to the paucity of studies that presented a direct link between nutrition and the risk of anovulatory infertility, this study aimed to summarize the most recent research on the influence of dietary factors on ovulation disorders and indicate the possibilities of future research.

The Problem of Malnutrition Associated with Major Depressive Disorder from a Sex-Gender Perspective

Major depressive disorder (MDD) is an incapacitating condition characterized by loss of interest, anhedonia and low mood, which affects almost 4% of people worldwide. With rising prevalence, it is considered a public health issue that affects economic productivity and heavily increases health costs alone or as a comorbidity for other pandemic non-communicable diseases (such as obesity, cardiovascular disease, diabetes, inflammatory bowel diseases, etc.). What is even more noteworthy is the double number of women suffering from MDD compared to men. In fact, this sex-related ratio has been contemplated since men and women have different sexual hormone oscillations, where women meet significant changes depending on the age range and moment of life (menstruation, premenstruation, pregnancy, postpartum, menopause…), which seem to be associated with susceptibility to depressive symptoms. For instance, a decreased estrogen level promotes decreased activation of serotonin transporters. Nevertheless, sexual hormones are not the only triggers that alter neurotransmission of monoamines and other neuropeptides. Actually, different dietary habits and/or nutritional requirements for specific moments of life severely affect MDD pathophysiology in women. In this context, the present review aims to descriptively collect information regarding the role of malnutrition in MDD onset and course, focusing on female patient and especially macro- and micronutrient deficiencies (amino acids, ω3 polyunsaturated fatty acids (ω3 PUFAs), folate, vitamin B12, vitamin D, minerals…), besides providing evidence for future nutritional intervention programs with a sex-gender perspective that hopefully improves mental health and quality of life in women.

Vitamin B12 Supplementation and Vitamin B12 Blood Serum Levels: Evaluation of Effect Modification by Gender and Smoking Status

Research suggests that high intake of supplemental vitamin B₁₂ may be associated with increased risk of cancer, with some evidence that this association may vary by gender and smoking status. This investigation evaluates if similar patterns in association are observed for data for 11,757 adults from the National Health and Nutrition Examination Survey (1999-2006). Survey-weighted multivariable-adjusted linear regression was used to evaluate the association between regular B₁₂ supplement use and log-transformed serum B₁₂ levels. Persons taking vitamin B₁₂ through a multivitamin/multimineral (MVMM) had a median supplemental intake of 12 mcg/day (Q1: 6, Q3: 25), compared to 100 mcg/day (Q1: 22, Q3: 500) for persons reporting supplemental B₁₂ intake through a MVMM-exclusive source. MVMM users had a geometric mean serum B12 26% (95% CI: 23%-30%) higher than nonusers, whereas MVMM-exclusive users' geometric mean was 61% (95% CI: 53%-70%) higher than nonusers (p-trend < 0.001). Although a positive trend (p-trend < 0.001) was observed for both men and women, the association was stronger among women (p-interaction < 0.001). No interaction was observed for smoking status (p-interaction = 0.45). B₁₂ supplementation is associated with higher levels of serum B₁₂, with significant interaction by gender but not smoking. Further work is needed to better understand the interplay of B₁₂ and gender.

Folate intake and ovarian reserve among women attending a fertility center

OBJECTIVE

To examine the association between dietary folate intake and antral follicle count (AFC) among women seeing treatment for infertility.

DESIGN

Cohort study.

SETTING

Academic fertility center.

PATIENTS

A total of 552 women attending the Massachusetts General Hospital Fertility Center (2007-2019) who participated in the Environment and Reproductive Health Study.

INTERVENTIONS

None. Folate intake was measured with a validated food frequency questionnaire at study entry. Multivariable Poisson regression models with robust standard errors were used to estimate the association of folate intake with AFC adjusting for calorie intake, age, body mass index, physical activity, education, smoking status, year of AFC, and intakes of vitamin B₁₂, iron, and vitamin D. Nonlinearity was assessed with restricted cubic splines.

MAIN OUTCOME MEASURE

AFC as measured by transvaginal ultrasonography as part of routine care.

RESULTS

Among the 552 women (median age, 35.0 years; median folate intake, 1,005 μg/d), total and supplemental folate intake had a significant nonlinear relationship with AFC. There was a positive linear association with AFC up to approximately 1,200 μg/d for total folate intake and up to 800 μg/d for supplemental folate intake; however, there was no additional benefit of higher folate intakes. The magnitude of the association was modest; for example, the predicted adjusted difference in AFC between a woman consuming 400 vs. 800 μg/d of supplemental folate was approximately 1.5 follicles.

CONCLUSION

Higher intake of folate, particularly from supplements, was associated with modestly higher ovarian reserve as measured by AFC among women attending a fertility center.

CLINICAL TRIAL REGISTRATION NUMBER

This trial was registered at clinicaltrials.gov as NCT00011713.

One-carbon metabolism during the menstrual cycle and pregnancy

Many enzymes in one-carbon metabolism (OCM) are up- or down-regulated by the sex hormones which vary diurnally and throughout the menstrual cycle. During pregnancy, estradiol and progesterone levels increase tremendously to modulate physiological changes in the reproductive system. In this work, we extend and improve an existing mathematical model of hepatic OCM to understand the dynamic metabolic changes that happen during the menstrual cycle and pregnancy due to estradiol variation. In particular, we add the polyamine drain on S-adenosyl methionine and the direct effects of estradiol on the enzymes cystathionine β-synthase (CBS), thymidylate synthase (TS), and dihydrofolate reductase (DHFR). We show that the homocysteine concentration varies inversely with estradiol concentration, discuss the fluctuations in 14 other one-carbon metabolites and velocities throughout the menstrual cycle, and draw comparisons with the literature. We then use the model to study the effects of vitamin B12, vitamin B6, and folate deficiencies and explain why homocysteine is not a good biomarker for vitamin deficiencies. Additionally, we compute homocysteine throughout pregnancy, and compare the results with experimental data. Our mathematical model explains how numerous homeostatic mechanisms in OCM function and provides new insights into how homocysteine and its deleterious effects are influenced by estradiol. The mathematical model can be used by others for further in silico experiments on changes in one-carbon metabolism during the menstrual cycle and pregnancy.

Female Fertility and the Nutritional Approach: The Most Essential Aspects

Infertility is an increasing problem that affects couples attempting pregnancy. A growing body of evidence points to a link between diet and female fertility. In fact, data show that a diet high in trans fats, refined carbohydrates, and added sugars can negatively affect fertility. Conversely, a diet based on the Mediterranean dietary patterns, i.e., rich in dietary fiber, omega-3 (ɷ-3) fatty acids, plant-based protein, and vitamins and minerals, has a positive impact on female fertility. An unhealthy diet can disrupt microbiota composition, and it is worth investigating whether the composition of the gut microbiota correlates with the frequency of infertility. There is a lack of evidence to exclude gluten from the diet of every woman trying to become pregnant in the absence of celiac disease. Furthermore, there are no data concerning adverse effects of alcohol on female fertility, and caffeine consumption in the recommended amounts also does not seem to affect fertility. On the other hand, phytoestrogens presumably have a positive influence on female fertility. Nevertheless, there are many unanswered questions with regard to supplementation in order to enhance fertility. It has been established that women of childbearing age should supplement folic acid. Moreover, most people experience vitamin D and iodine deficiency; thus, it is vital to control their blood concentrations and consider supplementation if necessary. Therefore, since diet and lifestyle seem to be significant factors influencing fertility, it is valid to expand knowledge in this area.

Effect of polymorphisms of MTHFR in controlled ovarian stimulation: a systematic review and meta-analysis

OBJECTIVE

Although several studies have reported a potential impact of methylenetetrahydrofolate reductase (MTHFR) polymorphisms on controlled ovarian stimulation (COS), the results remain controversial. The aim of the systematic review and meta-analysis was to evaluate the effect of MTHFR polymorphism on COS outcomes.

METHODS

PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials databases were searched up to December 2, 2020. COS clinical outcomes based on gene polymorphisms were included. Two reviewers independently extracted the data. The primary outcome was the number of oocytes retrieved. The secondary outcomes were the number of metaphase II (MII) oocytes, stimulation duration, basal follicle-stimulating hormone (FSH) level, FSH dosage, positive pregnancy test, ongoing pregnancy rate, clinical pregnancy rate, miscarriage rate, and live birth rate. Meta-analysis was performed using a fixed-effect model or random-effect model with Review Man 5.3.5. Mean difference (MD) with 95% confidence intervals (95%CIs) was calculated for continuous outcomes. The quality assessment of included studies was evaluated by using the Newcastle-Ottawa Scale.

RESULTS

Eleven studies were included in the systematic review, and seven studies with 2015 participants were included in the meta-analysis. Basal FSH level was significantly lower in CC homozygotes than TT homozygotes (four studies, 867 participants, MD - 0.54, 95%CI - 0.85 to - 0.23, P = 0.0006; I² = 0%) of MTHFR (rs1801133). FSH dose was significantly fewer in CC homozygotes compared with CT heterogeneous (three studies, 949 participants, MD - 75.78, 95%CI - 135.23 to - 16.33, P = 0.01; I² = 32%) or CT/TT model (three studies, 1097 participants, MD - 80.18, 95%CI - 135.54 to - 24.81, P = 0.005; I² = 42%). Differences in the oocytes retrieved and stimulation duration were insignificant. Gene variants on MTHFR (rs1801133) and MTHFR (rs1801131) were reported in ongoing pregnancy rate, clinical pregnancy rate, and live birth rate.

CONCLUSION

Studies to date indicate that polymorphisms of MTHFR could influence basal FSH level and FSH dose. The results could be useful to promote clinical practice on COS protocols. Further studies are needed to evaluate the clinical relevance of the multigene combination on COS.

Nutrition, one-carbon metabolism and arsenic methylation in Bangladeshi adolescents

BACKGROUND

Over 57 million people in Bangladesh are chronically exposed to arsenic-contaminated drinking water. Ingested inorganic arsenic (InAs) undergoes hepatic methylation generating monomethyl- (MMAs) and dimethyl- (DMAs) arsenic species in a process that facilitates urinary As (uAs) elimination. One-carbon metabolism (OCM), a biochemical pathway that is influenced by folate and vitamin B12, facilitates the methylation of As. OCM also supports nucleotide and amino acid synthesis, particularly during periods of rapid growth such as adolescence. While folate supplementation increases As methylation and lowers blood As (bAs) in adults, little data is available for adolescents.

OBJECTIVES

To examine the associations between OCM-related micronutrients and As methylation in Bangladeshi adolescents chronically exposed to As-contaminated drinking water.

METHODS

We conducted a cross-sectional study of 679 Bangladeshi adolescents, including 320 boys and 359 girls aged 14-16 years. Nutritional status was assessed by red blood cell (RBC) folate, plasma folate, plasma B12 and homocysteine (Hcys). Arsenic-related outcomes included blood arsenic (bAs), urinary arsenic (uAs), and urinary arsenic metabolites expressed as a percentage of total urinary As: %InAs, %MMAs, %DMAs.

RESULTS

Boys had significantly lower B12, higher Hcys, higher bAs, higher uAs, higher %MMAs, and a trend toward lower RBC folate compared to girls. Therefore, regression analyses controlling for water As and BMI were sex stratified. Among girls, RBC folate was inversely associated with bAs, plasma B12 was inversely associated with uAs, and plasma Hcys was inversely associated with %MMA. Among boys, plasma folate was inversely associated with %InAs and positively associated with %DMA, RBC folate was inversely associated with %InAs and positively associated with %MMA, while Hcys was positively associated with %InAs.

CONCLUSIONS

These findings suggest that associations between OCM nutritional status, bAs, and distribution of As metabolites in adolescents are similar to previously reported observations in adults and in children. The As methylation findings are statistically significant among boys but not among girls; this may be related to estrogen which more strongly influences OCM in females. The inverse association between Hcys and %MMA in girls is somewhat unexpected given that Hcys is known to be an indicator of impaired OCM and low folate/B12 in adults. Overall, these results indicate that the associations between OCM-related micronutrients and arsenic methylation in adolescents are generally similar to prior findings in adults, though these associations may differ by sex. Additionally, these findings suggest that more investigation into the role of Hcys in adolescent physiology is needed, perhaps particularly for girls. Additional studies are needed to evaluate the impact of OCM and As methylation on As-related adverse health outcomes (such as cancer and cardiovascular disease) in people exposed to As during adolescence.

Relationship between intake and plasma concentrations of vitamin B12 and folate in 873 adults with a physically active lifestyle: a cross-sectional study

BACKGROUND

Vitamin B12 and folate function as co-factors in pathways used during physical activity. Physical activity may therefore increase vitamin requirements, leading to a risk of deficient plasma concentrations. We aimed to investigate the relationship between intake and plasma concentrations of vitamin B12 and folate in physically active adults, as well as identify other determinants of vitamin B12 and folate plasma concentrations.

METHODS

The study population consisted of 873 adults (528 men and 345 women), aged 19-78 years, who participated in a 4-day walking event. The relationship between intake and plasma concentrations of vitamin B12 and folate was assessed using correlation and linear regression analyses. In addition, potential other determinants (sex, age, body mass index, energy intake and physical activity) of vitamin plasma concentrations were investigated.

RESULTS

Significant positive correlations were observed between intake and plasma concentrations of vitamin B12 [Pearson's correlation coefficient = 0.15; 95% confidence interval (CI) = 0.08-0.21] and folate (Pearson's correlation coefficient = 0.18; 95% CI = 0.12-0.25). In addition to vitamin intake, sex, age and energy intake were also determinants of both vitamin B12 and folate plasma concentrations in multivariable regression models.

CONCLUSIONS

The results suggest a positive association between intake and plasma concentrations for both vitamin B12 and folate in physically active people. By contrast to our hypothesis, physical activity was not a determinant of vitamin B12 and folate plasma concentrations. However, sex, age and energy intake were found to be determinants. Thus, when studying the relationship between intake and plasma concentrations of vitamin B12 or folate, these factors should be taken into account.

Emerging Trends in Research on Food Compounds and Women’s Fertility: A Systematic Review

Pro-healthy behaviours, including the diet, are significant factors in maintaining women’s fertility health. However, to improve the patient’s nutrition management, it is important to seek food-derived bioactive compounds to support fertility treatment. This review analysed recent studies of food compounds related to fertility, using databases including PubMed, Web of Science and Science Direct as well as PRISMA (preferred reporting items for systematic reviews) to ensure complete and transparent reporting of systematic reviews. This review lists foods associated with a higher birth rate, using original papers from the last five years (2015). The analysis included the impact of food compounds such as caffeine, fatty acids, folates and vitamin D, as well as the intake of fish, whole grains, dairy and soya. In addition, dietary patterns and total diet composition supporting women’s fertility were also analysed. The results will encourage further research on the relationship between food components and fertility.

Dietary Intakes of Vitamin B-2 (Riboflavin), Vitamin B-6, and Vitamin B-12 and Ovarian Cycle Function among Premenopausal Women

BACKGROUND

Riboflavin, vitamin B-6, and vitamin B-12 are key players in one-carbon metabolism as enzymatic cofactors, and deficiency of these nutrients may influence reproductive outcomes possibly through affecting reproductive hormones.

OBJECTIVE

The goal was to investigate associations between dietary intakes of riboflavin, vitamin B-6, and vitamin B-12, and menstrual function among premenopausal women.

DESIGN

This was a secondary analysis of a prospective cohort study conducted at the University at Buffalo during 2005 to 2007.

PARTICIPANTS/SETTING

Participants were 259 healthy, regularly menstruating women (aged 18 to 44 years) with self-reported menstrual cycles between 21 and 35 days, who were not trying to conceive, and who had not used hormonal contraception during the past 3 months.

MAIN OUTCOME MEASURES

Intakes of B vitamins were assessed via 24-hour dietary recalls four times per menstrual cycle for two cycles. Serum reproductive hormones and plasma homocysteine were measured eight and three times, respectively, per cycle for two cycles. Anovulatory cycles were determined by progesterone concentrations ≤5 ng/mL (15.9 nmol/L) and no observed serum luteinizing hormone peak during the mid or late luteal phase visit.

STATISTICAL ANALYSIS

Weighted linear mixed regressions were used to evaluate associations between cycle-averaged B vitamin intakes and hormones and homocysteine, and generalized linear regressions for associations with anovulation. Models were adjusted for age, race, body mass index, physical activity, alternate Mediterranean diet score, intakes of total energy, protein, fiber, and folate, and percentage of energy intake from fat.

RESULTS

Higher intakes of riboflavin (per 0.1 mg increase in intake) were inversely correlated with estradiol (-0.87%, 95% CI -1.67 to -0.06) and homocysteine levels (-0.61%, 95% CI -1.10 to -0.12). Higher vitamin B-6 intakes were suggestive of higher follicle-stimulating hormone, although the results were not statistically significant (0.63% difference, 95% CI -0.03 to 1.29, per 0.1 mg increase in intake; P=0.06). Small increases in testosterone and decreases in homocysteine were found with vitamin B-12 intake. No associations were observed between intake of B vitamins and a risk of sporadic anovulation.

CONCLUSIONS

Higher intakes of riboflavin were associated with a small decrease in serum estradiol among healthy, regularly menstruating women. Higher intakes of riboflavin and vitamin B-12 were associated with lower plasma homocysteine concentrations. Overall, riboflavin, vitamin B-6, and vitamin B-12 that are one-carbon nutrients do not appear to influence the ovarian cycle among premenopausal women.

Preconception folate status and reproductive outcomes among a prospective cohort of folate-replete women

BACKGROUND

Most studies of folate metabolism and reproduction have been conducted after pregnancy and in folate-deficient populations. However, measurement of maternal folate status preconceptionally may be most relevant to certain folate-linked early processes preceding a successful pregnancy, and there has been a major increase in folate concentrations in women of childbearing age in high resource settings.

OBJECTIVE

To examine associations between preconceptional biomarkers of maternal folate status (folate and homocysteine) and reproductive outcomes in folate-replete women.

STUDY DESIGN

Cohort nested within the Effects of Aspirin in Gestation and Reproduction trial, a block-randomized, double-blind, placebo-controlled trial whereby women were randomized to daily low-dose aspirin (81 mg/day) or placebo and all women received folic acid (400 μg/day). In total, 1228 women with 1-2 previous pregnancy losses and no documented infertility were recruited from 4 clinical sites in the United States (2006-2012) and were attempting pregnancy for up to 6 menstrual cycles. Log-binomial regression models were used to estimate relative risks and 95% confidence intervals between preconception serum folate and plasma homocysteine for anovulation, pregnancy, and pregnancy loss.

RESULTS

Greater plasma homocysteine was nonlinearly associated with greater risks of pregnancy loss only among women with 2 previous losses: a relative risk of 1.43 (95% confidence interval, 1.08-1.89) was found for plasma homocysteine concentrations at the study median of 8.0 μmol/L compared with a US population median of 6.0 μmol/L. No meaningful relationships were found between serum folate and any reproductive outcome or between plasma homocysteine and anovulation or becoming pregnant.

CONCLUSION

These data justify further study of the role of folate and homocysteine metabolism in normal and abnormal early pregnancy.

Dietary intake of nutrients involved in folate-mediated one-carbon metabolism and risk for endometrial cancer

BACKGROUND

Studies disagree as to whether intakes of folate-mediated one-carbon metabolism nutrients are associated with endometrial cancer.

METHODS

Using data from the large, prospective NIH-AARP Diet and Health Study, we used Cox proportional hazards models to evaluate endometrial cancer risk associated with calorie-adjusted dietary intake of several B vitamins and methionine. All models accounted for age, race, body mass index (BMI), smoking, oral-contraceptive use, menopausal hormone therapy use and caloric intake. We estimated associations by time from baseline (≤3 or >3 years) and stratified models by BMI (<25 or ≥25 kg/m2). During 16 years of follow-up, we identified 2329 endometrial cancer cases among 114 414 participants.

RESULTS

After adjustment for confounding, we observed increased risk for endometrial cancer with greater consumption of dietary total folate, natural folate, B2, B6 and B12 [hazard ratios (HRs) ranging from 1.14 to 1.24 for the highest quintile (Q5) vs the lowest (Q1)]. Higher intakes of total folate, natural folate, B6 and B12 continued to be associated with increased risk when limiting follow-up to >3 years from baseline. We observed risks for the highest intakes of B2 [Q5 vs Q1: HR 1.27 95% confidence interval (CI) 1.07-1.50], B12 (Q5 vs Q1: HR 1.38 CI 1.17-1.63) and methionine (Q5 vs Q1: HR 1.26 CI 1.07-1.48) among women who were overweight/obese, but not among normal/underweight women.

CONCLUSIONS

Our findings indicate that one-carbon metabolism plays a role in endometrial carcinogenesis and exploration of this role in tissue and cellular biology studies is warranted.

Comparison of ESI-MS/MS and APCI-MS methods for the quantification of folic acid analogs in C. elegans

Folic acid (FA) plays a vital role in central metabolism, including the one carbon cycle, nucleotide, and amino acid biosynthesis. The development of sensitive, accurate analytical methods to measure FA intermediates in tissues is critical to understand their biological roles in diverse physiological and pathological contexts. Here, we developed a highly sensitive method for the simultaneous quantification of FA intermediates in the nematode Caenorhabditis elegans as a model to dissect metabolic networks. The method was further validated by analyzing the worm folate pool upon RNAi knockdown of the dihydrofolate reductase gene dhfr-1. Comparative mass spectrometry behavior of the FA analogs using two different ion sources, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), revealed ESI-MS/MS to be more sensitive, but APCI-MS provided more detailed structure inferences, which can elucidate chemical investigation and synthesis of FA analogs. Finally, we report on the use of in vitro oxidation coupled with high-resolution mass spectrometry as a tool to discover new endogenous FA derivatives in the nematode.

One-Carbon Metabolism: Linking Nutritional Biochemistry to Epigenetic Programming of Long-Term Development

One-carbon (1C) metabolism comprises a series of interlinking metabolic pathways that include the methionine and folate cycles that are central to cellular function, providing 1C units (methyl groups) for the synthesis of DNA, polyamines, amino acids, creatine, and phospholipids. S-adenosylmethionine is a potent aminopropyl and methyl donor within these cycles and serves as the principal substrate for methylation of DNA, associated proteins, and RNA. We propose that 1C metabolism functions as a key biochemical conduit between parental environment and epigenetic regulation of early development and that interindividual and ethnic variability in epigenetic-gene regulation arises because of genetic variants within 1C genes, associated epigenetic regulators, and differentially methylated target DNA sequences. We present evidence to support these propositions, drawing upon studies undertaken in humans and animals. We conclude that future studies should assess the epigenetic effects of cumulative (multigenerational) dietary imbalances contemporaneously in both parents, as this better represents the human experience.