Folate administration decreases oxidative status and blood pressure in postmenopausal women

Contribution of serum elements to blood pressure during pregnancy by impacting gut microbiota: A prospective cohort study

Exposure to environmental elements can alter gut microbiota, further affecting host health. Exploring the interrelationships among element exposure, gut microbiota and blood pressure (BP) during pregnancy, as well as the mediating roles of gut microbiota, is warranted, which holds implications for maternal and offspring health. In a prospective cohort study between 2017-2018, 733 pregnant women were included. The serum elements and gut microbiota during the second trimester were assessed, and BP was collected during the second and third trimester and before delivery. Fourteen associations were identified between serum elements and BP, including positive associations of zinc (Zn) and thallium (Tl) with systolic BP during the second trimester. Rubidium (Rb) showed a positive association with Pielou's evenness. Serum elements, such as Tl and Rb, were significantly associated with the relative abundance of bacteria and co-abundance groups (CAGs). Alpha diversity was negatively associated with BP levels and trajectories. Moreover, 15 associations between gut microbiota and BP were shown. Finally, mediation analysis confirmed that CAG2 and Pielou's evenness mediated the associations of Tl and Rb with BP, respectively. We concluded that serum elements can contribute to BP changes during pregnancy through gut microbiota, suggesting gut microbiota-targeted approach as a potential intervention.

The Effect of Vitamin B12 Supplementation on Leukocyte Telomere Length in Mildly Stunted Nepalese Children: A Secondary Outcome of a Randomized Controlled Trial

BACKGROUND

Vitamin B12 is essential for deoxyribonucleic acid synthesis and genome stability. A deficiency of vitamin B12 is associated with telomere shortening, genomic aging, and increased risk of chronic disease and mortality.

OBJECTIVES

The study aims to determine the effect of vitamin B12 supplementation on leukocyte telomere length (LTL) in infants at risk of vitamin B12 deficiency.

METHODS

The study was a predefined secondary analysis of a randomized controlled trial enrolling 600 Nepalese infants aged 6 -11 mo, who were supplemented with 2 μg (2-3 recommended daily allowances) vitamin B12 or placebo daily for 1 y. At the end of the study, LTL was measured in 497 participants. Mean LTL was compared between the treatment arms in the full sample and predefined subgroups based on markers of vitamin B12 status, hemoglobin, sex, and growth indices.

RESULTS

LTL at end-study did not differ between the vitamin B12 and placebo arm with a standardized mean difference (95% confidence interval) of 0.04 (-0.14, 0.21). There was no effect of vitamin B12 on LTL in any of the subgroups.

CONCLUSIONS

Providing daily vitamin B12 for 1 y during infancy in a population at risk of vitamin B12 deficiency does not affect LTL. This trial was registered at clinicaltrials.gov as NCT02272842.

Systemic Oxidative Stress in Women with Ovarian and Pelvic Endometriosis: Role of Hormonal Therapy

This study was performed to evaluate the systemic oxidative stress balance in women with either ovarian or deep infiltrating endometriosis (DIE) and any alterations of the same during hormone therapy. Free oxygen radicals (FORT) and free oxidant radical defense (FORD) were measured in the capillary blood of 24 women without endometriosis, 26 women with endometrioma, and 26 women with DIE with or without endometrioma. Endometriosis was diagnosed by clinical and ultrasound assessment. Dietary factors, lifestyle habits, and intake of any substances interfering with the oxidative status were recorded. Women were prescribed contraceptive hormones, and the baseline assessments were repeated at the 3rd month of use, revealing a higher oxidative stress balance (FORT/FORD) in women with endometriosis than in controls (4.75 ± 4.4 vs. 2.79 ± 2.2; p = 0.05). The highest values were found in women with DIE (5.34 ± 4.6; p = 0.028 vs. controls). Regression analysis revealed an independent link between FORT/FORD and endometrioma (b 2.874, 95% CI 0.345, 5.403; p = 0.027) and DIE (b 4.419, 95% CI 1.775, 7.064; p = 0.001) but a negative correlation with HDL-cholesterol (b -0.063, 95% CI -0.125, -0.002; p = 0.043). In controls, the hormone therapy increased FORT (p = 0.003), but also FORD (p = 0.012), with the FORT/FORD balance remaining stable (2.72 ± 2.2 vs. 2.73 ± 1.8; p = 0.810). In women with endometriosis, FORT remained unchanged, but FORD increased (p = 0.004), and the FORT/FORD ratio significantly decreased (4.75 ± 4.4 vs. 2.57 ± 1.76; p = 0.002) to values similar to the control levels. These data indicate that systemic oxidative stress balance increased in women with endometriosis, particularly in those with DIE. The hormonal therapy did not change the oxidative stress balance in control women but significantly improved it in women with endometriosis, particularly those suffering from DIE.

Serum Folate Related to Five Measurements of Obesity and High-Sensitivity C-Reactive Protein in Korean Adults

This study investigated the effects of folic acid on obesity and high-sensitivity C-reactive protein (CRP) levels. Using data from the Korea National Health and Nutrition Examination Survey (KNHANES VII 2016–2018), 6394 adults (aged 19–80 years) who met the study criteria were identified and divided into young, middle-aged, and older adult groups. The analysis assessed associations using logistic regression for complex samples. Obesity was measured using body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), a body shape index (ABSI), and body roundness index (BRI). The odds ratio (OR) of obesity based on BMI were statistically significant for young adults and older participants with low levels of folic acid compared to those with high levels (OR: 1.33 and 1.58, respectively). The OR of obesity based on BMI, WC, WHtR, ABSI, and BRI was significant with low levels of folic acid in middle-aged individuals (OR: 1.36, 1.32, 1.41, 1.29, and 1.47, respectively). Low folate levels were related to higher high-sensitivity CRP levels in middle-aged patients. In conclusion, folate level showed a significant inverse association with obesity and inflammatory biomarkers, especially in the middle-aged group. Further longitudinal or randomized controlled trials are needed to confirm and expand our results.

Dietary factors that affect the risk of pre-eclampsia

Pre-eclampsia affects 3%–5% of pregnant women worldwide and is associated with a range of adverse maternal and fetal outcomes, including maternal and/or fetal death. It particularly affects those with chronic hypertension, pregestational diabetes mellitus or a family history of pre-eclampsia. Other than early delivery of the fetus, there is no cure for pre-eclampsia. Since diet or dietary supplements may affect the risk, we have carried out an up-to-date, narrative literature review to assess the relationship between nutrition and pre-eclampsia. Several nutrients and dietary factors previously believed to be implicated in the risk of pre-eclampsia have now been shown to have no effect on risk; these include vitamins C and E, magnesium, salt, ω-3 long-chain polyunsaturated fatty acids (fish oils) and zinc. Body mass index is proportionally correlated with pre-eclampsia risk, therefore women should aim for a healthy pre-pregnancy body weight and avoid excessive gestational and interpregnancy weight gain. The association between the risk and progression of the pathophysiology of pre-eclampsia may explain the apparent benefit of dietary modifications resulting from increased consumption of fruits and vegetables (≥400 g/day), plant-based foods and vegetable oils and a limited intake of foods high in fat, sugar and salt. Consuming a high-fibre diet (25–30 g/day) may attenuate dyslipidaemia and reduce blood pressure and inflammation. Other key nutrients that may mitigate the risk include increased calcium intake, a daily multivitamin/mineral supplement and an adequate vitamin D status. For those with a low selenium intake (such as those living in Europe), fish/seafood intake could be increased to improve selenium intake or selenium could be supplemented in the recommended multivitamin/mineral supplement. Milk-based probiotics have also been found to be beneficial in pregnant women at risk. Our recommendations are summarised in a table of guidance for women at particular risk of developing pre-eclampsia.

Inverse Association of Serum Folate Level with Metabolic Syndrome and Its Components in Korean Premenopausal Women: Findings of the 2016–2018 Korean National Health Nutrition Examination Survey

Research on the association of serum folate levels with metabolic syndrome (MetS) in premenopausal women is lacking. This study was aimed to investigate this association in 1730 premenopausal women using the 2016 to 2018 Korean National Health and Nutrition Examination Survey data. Participants’ mean age and BMI were 35.9 years and 22.7 kg/m2, respectively. Participants were divided into three groups according to serum folate tertiles. Odds ratios (OR) and 95% confidence intervals (CIs) for abdominal obesity, elevated blood pressure (BP), high fasting plasma glucose (FPG), high triglycerides (TG), low high-density lipoprotein cholesterol (HDL-C), and MetS were calculated in multiple logistic regression models adjusted for possible confounders, by serum folate level tertiles. Prevalence of MetS (14.9, 11.0, and 8.6%); abdominal obesity (17.8, 16.0, and 11.4%); high TG (17.5, 14.0, and 11.1%); and low HDL-C (50.3, 44.6, and 42.5%) decreased with increasing folate level tertile. Prevalence of elevated BP (14.3, 12.0, and 11.7%) and high FPG (11.9, 15.8, and 13.0%) showed no significant differences according to serum folate level tertiles. The multivariate-adjusted ORs (95% CIs) for MetS, abdominal obesity, elevated BP, high TG, and low HDL-C in the highest folate level tertile were 2.17 (1.46–3.22), 1.80 (1.25–2.60), 1.77 (1.16–2.70), 1.90 (1.35–2.67), and 1.49 (1.14–1.94), respectively. The ORs for high FPG did not show significant differences according to serum folate level tertiles. In conclusion, serum folate levels were inversely associated with an increased risk of MetS in Korean premenopausal women. These results suggest that MetS can be prevented and managed by improving the serum folate levels in premenopausal women.

The significance of homocysteine in patients with hypertension

Cardiovascular disease is the most common cause of death in developed countries. Important factors leading to ischemic heart disease and strokes are hypertension and high levels of homocysteine in blood serum. The coexistence of these two factors significantly increases the risk of these diseases and premature deaths. Many studies indicate that patients with hypertension are significantly more likely to demonstrate increased blood serum homocysteine levels than those with normal blood pressure. This may be caused by a higher incidence of overweight, high intake of salt and increased uric acid levels. It has been shown that both these factors increase the prevalence of hypertension and lead to higher homocysteine levels. However, the results of some studies indicate that arterial hypertension and homocysteinemia are causally related. It was shown, among other things, that high homocysteine levels damage the endothelium and reduce nitric oxide synthesis, which may directly lead to hypertension. Serum homocysteine levels are slightly higher in patients with white coat hypertension than they are in healthy individuals and may therefore also increase the risk of cardiovascular diseases. Several authors have also shown that the levels of homocysteine in blood serum are higher in so-called non-dippers, i.e., patients with no night-time pressure drop. The lack of a 10%–20% decrease in blood pressure at night is associated with increased cardiovascular complications. Strokes occur especially frequently in older people with arterial hypertension and hyperhomocysteinemia. The administration of B vitamins and folic acid significantly reduces serum homocysteine levels. The administration of this acid also slightly, but statistically significantly, increases the effectiveness of hypotensive drugs. Large meta-analyses meta-analysis indicate that the increased supply of folic acid in patients with hypertension significantly reduces the risk of stroke. Such management is particularly effective in patients with hypertension and hyperhomocysteinemia.

Folic acid supplementation and blood pressure: a GRADE-assessed systematic review and dose-response meta-analysis of 41,633 participants

Hypertension is a predisposing factor for cardiovascular disease (CVD). The extant literature regarding the effects of folic acid supplementation on blood pressure (BP) is inconsistent. Therefore, this systematic review and meta-analysis of randomized controlled trials was conducted to summarize the effects of folic acid supplementation on BP. A systematic search was carried out in PubMed, Scopus, ISI Web of Science, and Cochrane library, from database inception to August 2021. Data were pooled using the random-effects method and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). The pooled results of 22 studies, including 41,633 participants, showed that folic acid supplementation significantly decreased systolic BP (SBP) (WMD: -1.10 mmHg; 95% CI: -1.93 to -0.28; p = 0.008). Subgroup analysis showed that the results remained significant when baseline SBP was ≥120 mmHg, intervention duration was ≤6 weeks, intervention dose was ≥5 mg/d, in patients with CVD, males and females, and overweight participants, respectively. Furthermore, the changes observed in diastolic BP (DBP) (WMD: -0.24 mmHg; 95% CI: -0.37 to -0.10; p < 0.001) were also statistically significant. However, subgroup analysis showed that the results remained significant in subject with elevated DBP, long term duration of intervention (>6 weeks), low dose of folic acid (<5 mg/day), CVD patients, both sexes and male, and participants with normal BMI. Dose-response analysis showed that folic acid supplementation changed SBP and DBP significantly based on dose and duration. However, meta-regression analysis did not reveal any significant association between dose and duration of intervention with changes in SBP. The present study demonstrates the beneficial effects of folic acid supplementation on BP by decreasing both SBP and DBP.

Folic Acid Supplementation Improves Glycemic Control for Diabetes Prevention and Management: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

Background: There is a growing interest in the considerable benefits of dietary supplementations, such as folic acid, on the glycemic profile. We aimed to investigate the effects of folic acid supplementation on glycemic control markers in adults. Methods: Randomized controlled trials examining the effects of folic acid supplementation on glycemic control markers published up to March 2021 were detected by searching online databases, including Scopus, PubMed, Embase, and ISI web of science, using a combination of related keywords. Mean change and standard deviation (SD) of the outcome measures were used to estimate the mean difference between the intervention and control groups at follow-up. Meta-regression and non-linear dose-response analysis were conducted to evaluate the association between pooled effect size and folic acid dosage (mg/day) and duration of the intervention (week). From 1814 detected studies, twenty-four studies reported fasting blood glucose (FBG), fasting insulin, hemoglobin A1C (HbA1C), and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) as an outcome measure. Results: Results revealed significant reductions in FBG (weighted mean difference (WMD): −2.17 mg/dL, 95% CI: −3.69, −0.65, p = 0.005), fasting insulin (WMD: −1.63 pmol/L, 95% CI: −2.53, −0.73, p < 0.001), and HOMA-IR (WMD: −0.40, 95% CI: −0.70, −0.09, p = 0.011) following folic acid supplementation. No significant effect was detected for HbA1C (WMD: −0.27%, 95% CI: −0.73, 0.18, p = 0.246). The dose-response analysis showed that folic acid supplementation significantly changed HOMA-IR (r = −1.30, p-nonlinearity = 0.045) in non-linear fashion. However, meta-regression analysis did not indicate a linear relationship between dose, duration, and absolute changes in FBG, HOMA-IR, and fasting insulin concentrations. Conclusions: Folic acid supplementation significantly reduces some markers of glycemic control in adults. These reductions were small, which may limit clinical applications for adults with type II diabetes. Further research is necessary to confirm our findings.

Oxidative Stress Is Increased in Combined Oral Contraceptives Users and Is Positively Associated with High-Sensitivity C-Reactive Protein

Information concerning the mechanisms underlying oxidative stress and low-grade inflammation in young healthy women predisposing eventually to future diseases is scarce. We investigated the relationship of oxidative stress and high-sensitivity C-reactive protein (hsCRP) in fertile-age women by oral combined contraceptive (OC) use. Caucasian Italian healthy non-obese women (n = 290; 100 OC-users; 190 non-OC-users; mean age 23.2 ± 4.7 years) were analyzed. Blood hydroperoxides, as oxidative stress biomarkers, were assessed by Free Oxygen Radical Test (FORT). Serum hsCRP was determined by an ultra-sensitive method (hsCRP). Markedly elevated oxidative stress (≥400 FORT Units) was found in 77.0% of OC-users and 1.6% of non-OC-users, odds ratio (OR) = 209, 95% CI = 60.9–715.4, p < 0.001. Elevated hsCRP levels ≥ 2.0 mg/L, considered risky for cardiovascular diseases (CVDs), were found in 41.0% of OC-users and 9.5% of non-OC-users, OR = 6.6, 95%CI 3.5–12.4, p < 0.001. Hydroperoxides were strongly positively correlated to hsCRP in all women (r_s = 0.622, p < 0.001), in OC-users (r_s = 0.442, p < 0.001), and in non-OC-users (r_s = 0.426, p < 0.001). Women with hydroperoxides ≥ 400 FORT Units were eight times as likely to have hsCRP ≥ 2 mg/L. In non-OC-users only, hydroperoxides values were positively correlated with weight and body mass index, but negatively correlated with red meat, fish and chocolate consumption. Our research is the first finding a strong positive correlation of serum hydroperoxides with hsCRP, a marker of low-grade chronic inflammation, in young healthy women. Further research is needed to elucidate the potential role of these two biomarkers in OC-use associated side-effects, like thromboembolism and other CVDs.

The effect of folate on ischemia/reperfusion injury in a rat adnexal torsion model

PURPOSE

The ischemia/reperfusion (I/R) injury of ovaries in adnexal torsion may have inadvertent consequences. Many agents have been studied in terms of their ability to prevent reperfusion damage to ovaries in suspected cases. In this study, folic acid, known to have antioxidative properties, was investigated to determine whether it played a role in the prevention of I/R damage in a rat ovarian torsion model.

METHODS

In this experimental study, 40 female adult Wistar-Albino rats were randomly divided into five groups as control, ischemia, I/R, Fol2 (2 mg/kg folic acid), and Fol4 (4 mg/kg folic acid). In the Fol2 and Fol4 groups, folic acid was intraperitonelly administered 30 min before reperfusion. Blood samples were obtained from the tails of each rat at the second hour of reperfusion.

RESULTS

The total oxidant status (TOS), total antioxidant status, cystatin C and folic acid levels of the five groups were investigated. Folic acid in 2 mg/kg dose could moderately increase the serum folic acid concentration (15.75-19.95 ng/ml, p < 0.05), reduce the level of cystatin C (0.18-0.12 μg/L, p < 0.05), and had a tendency to improve the oxidative stress injury (OSI: 76.05-33.06, p > 0.05), although there was no statistical difference in TOS levels (p = 0.07). Folic acid in 4 mg/kg dose, could significantly increase the serum folic acid concentration (15.75-37.65 ng/ml). However, it did not significantly reduce the level of cystatin C (0.18-0.19 μg/L, p > 0.05), and did not improve oxidative stress injury (76.05-130.58, p > 0.05).

CONCLUSION

Folic acid in 2 mg/kg dose might improve the ovarian I/R injury though this was not statistically significant. Further studies are required to reach a definitive conclusion about the protective effect of folic acid in I/R injury.

Intakes of Folate, Vitamin B6, and Vitamin B12 in Relation to Diabetes Incidence Among American Young Adults: A 30-Year Follow-up Study

OBJECTIVE

To prospectively examine intakes of folate, vitamin B₆, and vitamin B₁₂ in relation to diabetes incidence in a large U.S. cohort.

RESEARCH DESIGN AND METHODS

A total of 4,704 American adults aged 18-30 years and without diabetes were enrolled in 1985-1986 and monitored until 2015-2016 in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Dietary assessment was conducted by a validated dietary history questionnaire at baseline, in 1992-1993, and in 2005-2006. The cumulative average intakes of folate, vitamin B₆, and vitamin B₁₂ were used in the analyses. Incident diabetes was ascertained by plasma glucose levels, oral glucose tolerance tests, hemoglobin A_1c concentrations, and/or antidiabetic medications.

RESULTS

During 30 years (mean 20.5 ± 8.9) of follow-up, 655 incident cases of diabetes occurred. Intake of folate, but not vitamin B₆ or vitamin B₁₂, was inversely associated with diabetes incidence after adjustment for potential confounders. Compared with the lowest quintile of total folate intake, the multivariable-adjusted hazard ratios (95% CI) in quintiles 2-5 were 0.85 (0.67-1.08), 0.78 (0.60-1.02), 0.82 (0.62-1.09), and 0.70 (0.51-0.97; P _trend = 0.02). Higher folate intake was also associated with lower plasma homocysteine (P _trend < 0.01) and insulin (P _trend < 0.01). Among supplement users, folate intake was inversely associated with serum C-reactive protein levels (P _trend < 0.01).

CONCLUSIONS

Intake of folate in young adulthood was inversely associated with diabetes incidence in midlife among Americans. The observed association may be partially explained by mechanisms related to homocysteine level, insulin sensitivity, and systemic inflammation.

Serum and Dietary Folate and Vitamin B12 Levels Account for Differences in Cellular Aging: Evidence Based on Telomere Findings in 5581 U.S. Adults

Folate and vitamin B₁₂ are essential for a variety of metabolic processes. Both micronutrients have been shown to reduce oxidative stress significantly. The present cross-sectional investigation evaluated the association between serum and dietary folate and vitamin B₁₂ levels and leukocyte telomere length, an index of cellular aging influenced by oxidative stress. The study included 5581 adults from the National Health and Nutrition Examination Survey (NHANES). Because participants were randomly selected, results are generalizable to all civilian, noninstitutionalized U.S. adults. A blood draw provided DNA and serum folate and B₁₂ information. The quantitative polymerase chain reaction method was used to measure telomere length. The Bio-Rad Quantaphase II folate and vitamin B₁₂ radioassay kit was used to quantify levels of folate and vitamin B₁₂. Dietary folate and vitamin B₁₂ were assessed using a multipass 24 h recall. In some models, age, race, smoking pack-years, alcohol use, body mass index, total physical activity, hours fasted before the blood draw, and diabetes status were employed as covariates to minimize their influence. Findings showed that for each additional year of chronological age, telomeres were 15.6 base pairs shorter, on average (F = 378.8, p < 0.0001). Men had shorter telomeres than women after adjusting for all the covariates (F = 6.8, p = 0.0146). Serum (F = 10.5, p = 0.0030) and dietary (F = 5.0, p = 0.0325) folate concentrations were each linearly related to telomere length in women, but not in men, after controlling for age and race. Serum vitamin B₁₂ and telomere length had a nonsignificant, inverse relationship in women, with age and race controlled (F = 2.8, p = 0.1056), but no relation in men. Dietary vitamin B₁₂ was linearly related to telomere length in women, after adjusting for age and race (F = 4.3, p = 0.0468), but not in men. Overall, evidence indicates that folate and vitamin B₁₂ levels, especially folate, account for meaningful differences in cell aging in women, but not in men.

The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Observationally, homocysteine is associated with higher risk of diabetes. Folate, which reduces homocysteine, is promising for the prevention and treatment of diabetes. Previous meta-analysis of three trials suggested folate might lower hemoglobin A1c (HbA1c).

METHODS

An updated systematic review and meta-analysis of placebo-controlled randomized trials was conducted. We searched PubMed using ("folate" or "folic acid") and trial and ("glucose" or "diabetes" or "insulin" or "hemoglobin A1c" or "HbA1c") in any field until February 3, 2017. We also conducted a bibliographic search of selected studies and relevant reviews. Relative risk of diabetes and mean differences in indicators of glucose metabolism between folate and placebo were summarized in a meta-analysis using inverse variance weighting with random effects. Heterogeneity, publication bias, and risk of bias were also assessed.

RESULTS

Eighteen trials of 21,081 people with/without diabetes were identified. Folate decreased fasting glucose (-0.15 mmol/L, 95% confidence interval [CI] -0.29 to -0.01), homeostatic model assessment-insulin resistance (-0.83, 95% CI -1.31 to -0.34), and insulin (-1.94 μIU/mL, 95% CI -3.28 to -0.61) but had no clear effect on diabetes or HbA1c.

CONCLUSIONS

Our study suggests a potential benefit of folate on insulin resistance and glycemic control; the latter requires examination in more high-quality trials.

Plasma Homocysteine Levels Are Associated With Circadian Blood Pressure Variation in Chinese Hypertensive Adults

BACKGROUND

Homocysteine-lowering intervention with folate was recently shown to be able to increase day-night difference of blood pressure (BP) in humans indicating a potential relationship between homocysteine and circadian BP variation. We thus sought to investigate the association between plasma total homocysteine level (tHcy) and circadian BP variation in hypertensive adults.

METHODS

We enrolled 244 eligible dipping and 249 nondipping BP status adults from 560 adults who were randomly sampled from 5,233 Chinese hypertensive adults who received ambulatory BP monitoring (ABPM). We further enrolled 390 adults with CC/CT genotypes of the methylenetetrahydrofolate reductase (MTHFR) and 79 TT genotype who received ABPM at the same time from 1858 hypertensive adults with MTHFR polymorphisms detection.

RESULTS

Plasma tHcy in nondippers was significantly higher than dippers (P < 0.001). Simple linear analysis revealed that tHcy significantly correlated with nocturnal systolic BP fall (r = -0.145, P = 0.001) and diastolic BP fall (r = -0.141, P = 0.002). Multivariate logistic regression analysis further identified tHcy as an independent factor correlated with the presence of nondipping BP status in hypertensive adults (odds ratio: 1.873, 95% confidence interval: 1.171-2.996, P = 0.009). The percentage of dipping BP status was 19.49% or 8.86% and the percentage of nondipping BP status was 80.51% or 91.14% in CC/CT or TT genotypes, respectively. The above different between CC/CT and TT genotypes was significant (P = 0.024).

CONCLUSIONS

These results indicated that high homocysteine levels associate with disturbed circadian BP variation in Chinese hypertensive adults.

Role of folic acid in nitric oxide bioavailability and vascular endothelial function

Folic acid is a member of the B-vitamin family and is essential for amino acid metabolism. Adequate intake of folic acid is vital for metabolism, cellular homeostasis, and DNA synthesis. Since the initial discovery of folic acid in the 1940s, folate deficiency has been implicated in numerous disease states, primarily those associated with neural tube defects in utero and neurological degeneration later in life. However, in the past decade, epidemiological studies have identified an inverse relation between both folic acid intake and blood folate concentration and cardiovascular health. This association inspired a number of clinical studies that suggested that folic acid supplementation could reverse endothelial dysfunction in patients with cardiovascular disease (CVD). Recently, in vitro and in vivo studies have begun to elucidate the mechanism(s) through which folic acid improves vascular endothelial function. These studies, which are the focus of this review, suggest that folic acid and its active metabolite 5-methyl tetrahydrofolate improve nitric oxide (NO) bioavailability by increasing endothelial NO synthase coupling and NO production as well as by directly scavenging superoxide radicals. By improving NO bioavailability, folic acid may protect or improve endothelial function, thereby preventing or reversing the progression of CVD in those with overt disease or elevated CVD risk.

Folic acid and diseases - supplement it or not?

INTRODUCTION

folic acid is a water soluble vitamin, which is synthetically-produced and found in fortified foods and supplements. Folate is found naturally in plants, such as the dark green leafy vegetables. Folate is not synthesized de novo by humans, therefore the daily requirements are met from the dietary intake of folic acid supplements or food rich in this vitamin. Folate deficiency could lead to numerous common health problems. Hyperhomocysteinemia and the possibility of malignancy developments are the long term consequences of this deficit albeit contradictory findings on these claims.

METHODS

the articles included in this review focused on recent updated evidence-based reports and meta-analyses on the associations of the serum folate/folic acid and the various diseases found globally.

RESULTS

the benefit of folic acid supplementation in the pre-conception period for the prevention of neural tube defects (NTDs) was well established and it was suggested that counseling sessions should be given to women with previous pregnancies affected by NTDs. However, supplementation of folic acid and its medicinal effects in the treatment of other diseases were contradictory and unclear.

CONCLUSION

more detailed investigations into the health benefits of folic acid are needed before it could be recommended for supplementation, treatment or prevention of some of the diseases discussed in this review.

Novel Approaches to Investigate One-Carbon Metabolism and Related B-Vitamins in Blood Pressure

Hypertension, a major risk factor for heart disease and stroke, is the world's leading cause of preventable, premature death. A common polymorphism (677C→T) in the gene encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR) is associated with increased blood pressure, and there is accumulating evidence demonstrating that this phenotype can be modulated, specifically in individuals with the MTHFR 677TT genotype, by the B-vitamin riboflavin, an essential co-factor for MTHFR. The underlying mechanism that links this polymorphism, and the related gene-nutrient interaction, with hypertension is currently unknown. Previous research has shown that 5-methyltetrahydrofolate, the product of the reaction catalysed by MTHFR, appears to be a positive allosteric modulator of endothelial nitric oxide synthase (eNOS) and may thus increase the production of nitric oxide, a potent vasodilator. Blood pressure follows a circadian pattern, peaking shortly after wakening and falling during the night, a phenomenon known as 'dipping'. Any deviation from this pattern, which can only be identified using ambulatory blood pressure monitoring (ABPM), has been associated with increased cardiovascular disease (CVD) risk. This review will consider the evidence linking this polymorphism and novel gene-nutrient interaction with hypertension and the potential mechanisms that might be involved. The role of ABPM in B-vitamin research and in nutrition research generally will also be reviewed.

Serum Folate Shows an Inverse Association with Blood Pressure in a Cohort of Chinese Women of Childbearing Age: A Cross-Sectional Study

Background

It has been reported that higher folate intake from food and supplementation is associated with decreased blood pressure (BP). The association between serum folate concentration and BP has been examined in few studies. We aim to examine the association between serum folate and BP levels in a cohort of young Chinese women.

Methods

We used the baseline data from a pre-conception cohort of women of childbearing age in Liuyang, China, for this study. Demographic data were collected by structured interview. Serum folate concentration was measured by immunoassay, and homocysteine, blood glucose, triglyceride and total cholesterol were measured through standardized clinical procedures. Multiple linear regression and principal component regression model were applied in the analysis.

Results

A total of 1,532 healthy normotensive non-pregnant women were included in the final analysis. The mean concentration of serum folate was 7.5 ± 5.4 nmol/L and 55% of the women presented with folate deficiency (< 6.8 nmol/L). Multiple linear regression and principal component regression showed that serum folate levels were inversely associated with systolic and diastolic BP, after adjusting for demographic, anthropometric, and biochemical factors.

Conclusions

Serum folate is inversely associated with BP in non-pregnant women of childbearing age with high prevalence of folate deficiency.

Potential role of folate in pre-eclampsia

Dietary deficiencies of folate and other B vitamin cofactors involved in one-carbon metabolism, together with genetic polymorphisms in key folate-methionine metabolic pathway enzymes, are associated with increases in circulating plasma homocysteine, reduction in DNA methylation patterns, and genome instability events. All of these biomarkers have also been associated with pre-eclampsia. The aim of this review was to explore the literature and identify potential knowledge gaps in relation to the role of folate at the genomic level in either the etiology or the prevention of pre-eclampsia. A systematic search strategy was designed to identify citations in electronic databases for the following terms: folic acid supplementation AND pre-eclampsia, folic acid supplementation AND genome stability, folate AND genome stability AND pre-eclampsia, folic acid supplementation AND DNA methylation, and folate AND DNA methylation AND pre-eclampsia. Forty-three articles were selected according to predefined selection criteria. The studies included in the present review were not homogeneous, which made pooled analysis of the data very difficult. The present review highlights associations between folate deficiency and certain biomarkers observed in various tissues of women at risk of pre-eclampsia. Further investigation is required to understand the role of folate in either the etiology or the prevention of pre-eclampsia.