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

Betaine and B12 Intake, Glutathione Concentration, and MTHFR, PEMT, and MTHFD1 Genotypes Are Associated with Diabetes-Related Parameters in Polish Adults

BACKGROUND

There is a growing body of evidence on associations between one-carbon metabolism (OCM) and diabetes-related parameters. For this reason, we aimed to examine the associations of plasma choline, betaine, trimethylamine N-oxide (TMAO), glutathione (GSH), serum folate, vitamin B12, dihydrofolate reductase (rs70991108) genotype, methylenetetrahydrofolate reductase (MTHFR) (rs180113) genotype, methylenetetrahydrofolate dehydrogenase (MTHFD1) (rs2236225) genotype, and phosphatidylethanolamine N-methyltransferase (rs7946 and rs12325817) genotype with fasting glucose level, insulin level, and diabetes-related indices.

METHODS

The study group consisted of 421 Polish adults aged 20-40 y. Food intake was assessed using a 3-d food diary. Plasma concentrations of choline, betaine, and TMAO were determined by ultra-high-performance liquid chromatography-electrospray ionization mass spectrometry. The total plasma GSH level was measured by high-performance liquid chromatography. Insulin, folate, and vitamin B12 concentrations were estimated by enzyme-linked immunosorbent assay method. Genotyping was performed with TaqMan probes.

RESULTS

GSH level was negatively associated with insulin (β = -0.11, P < 0.05) and gamma-glutamyl transferase (GGTP) (β = -0.12, P < 0.05), and positively associated with fasting glucose (β = 0.11, P < 0.05). Betaine intake was negatively associated with serum insulin concentration (β = -0.13, P < 0.05) and HOMA-IR (β = -0.12, P < 0.05). Choline intake was negatively associated with insulin (β = -0.17, P < 0.01). Serum folate level was negatively associated with GGTP (β = -0.11; P < 0.05). The methylenetetrahydrofolate reductase (MTHFR) CC genotype was associated with higher serum insulin levels (β = 0.15; P < 0.01) and higher HOMA-IR (β = 0.15, P < 0.01), whereas the MTHFD1 AA genotype was negatively associated with Quantitative Insulin Sensitivity Check Index (β = -0.11, P < 0.05).

CONCLUSIONS

Our findings suggest that higher GSHL and higher intake of betaine, B12, and choline, as well as the TT genotype of MTHFR and the AA genotype of MTHFD1, are associated with lower diabetes-related parameters among adults.

Association between serum pyridoxal 5'-phosphate levels and all-cause, cardiovascular mortality, and cardiovascular disease in adults: a population-based cohort study

Background

The association between pyridoxal 5'-phosphate (PLP) and cardiovascular disease (CVD) remains a topic of discussion.

Objectives

This study aimed to explore the relationship between serum PLP levels and the incidence of all-cause mortality, cardiovascular mortality, and the risk of CVD among the US population.

Design

A population-based cohort study.

Methods

This study analyzed data from the National Health and Nutrition Examination Survey. Adjusted hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were calculated using weighted Cox proportional hazards regression models to assess the risk associated with all-cause and cardiovascular mortality. Weighted binary logistic regression was utilized to assess the relationship between serum PLP levels and the risk of CVD. Nonlinear associations were evaluated using multivariable-adjusted restricted cubic splines.

Results

There were 2546 cases of all-cause mortality and 867 cases of cardiovascular mortality over a mean follow-up of 11.36 years. In the fully adjusted model, the adjusted HRs with 95% CIs for all-cause mortality associated with increases in serum PLP levels corresponding to the interquartile ranges were 0.83 (0.74-0.93), 0.71 (0.63-0.80), and 0.64 (0.56-0.74), respectively. Similarly, cardiovascular mortality decreased by 0.78 (0.62-0.97), 0.63 (0.49-0.81), and 0.62 (0.50-0.77) with each quartile increase in serum PLP levels. Higher serum PLP levels confer protection against CVD risk (odds ratio: 0.87, 95% CI: 0.79-0.96). Serum PLP levels showed nonlinear relationships with risk of all-cause mortality, cardiovascular mortality, and CVD.

Conclusion

The results of this study provide evidence that serum PLP serves as a protective factor against all-cause mortality, cardiovascular mortality, and CVD in US adults, with dose-response relationships.

Oxidative balance score as a useful predictive marker for new-onset type 2 diabetes mellitus in Korean adults aged 60 years or older: The Korean Genome and Epidemiologic Study-Health Examination (KoGES-HEXA) cohort

BACKGROUND

The oxidative balance score (OBS) is a comprehensive pro- and anti-oxidative marker for assessing the risk of various metabolic diseases and cancers. However, it is not well established whether OBS is related to type 2 diabetes mellitus (T2DM), particularly in elderly populations. Therefore, our objective was to investigate the longitudinal effect of OBS on T2DM in a large cohort of Korean adults aged 60 years and older.

METHODS

We assessed the data for 3516 participants aged 60 years and older without diabetes mellitus from the Health Examinees cohort of the Korean Genome and Epidemiology Study. We classified the participants into three groups according to OBS tertiles. We prospectively assessed hazard ratios (HRs) with 95 % confidence intervals (CIs) for new-onset T2DM using multivariable Cox proportional-hazard regression models during the mean 3.5 years following the baseline survey.

RESULTS

A total of 109 participants (3.1 %) developed T2DM during a mean follow-up of 3.5 years. The incidence rates per 1000 person-years were 11.73 for the lowest OBS tertile (T1), 8.19 for the second tertile (T2), and 6.23 for the highest tertile (T3). Adjusting for all confounding factors, compared with the referent T1, the HR (95 % CI) of new-onset T2DM was not significant in T2 (0.71 [0.47-1.07]) but was significant in T3 at (0.47 [0.30-0.75]) (p for trend = 0.002).

CONCLUSIONS

The study suggests that a OBS could serve as a valuable predictive marker for new-onset T2DM in older adults. Our study suggests that maintaining an appropriate body weight through healthy lifestyle modification has the potential to lower T2DM incidence in elderly. This implies that the OBS may be a useful tool for assessing the incidence of T2DM even in older individuals.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Vitamin B6 and diabetes and its role in counteracting advanced glycation end products

Naturally occurring forms of vitamin B6 include six interconvertible water-soluble compounds: pyridoxine (PN), pyridoxal (PL), pyridoxamine (PM), and their respective monophosphorylated derivatives (PNP, PLP, and PMP). PLP is the catalytically active form which works as a cofactor in approximately 200 reactions that regulate the metabolism of glucose, lipids, amino acids, DNA, and neurotransmitters. Most of vitamers can counteract the formation of reactive oxygen species and the advanced glycation end-products (AGEs) which are toxic compounds that accumulate in diabetic patients due to prolonged hyperglycemia. Vitamin B6 levels have been inversely associate with diabetes, while vitamin B6 supplementation reduces diabetes onset and its vascular complications. The mechanisms at the basis of the relation between vitamin B6 and diabetes onset are still not completely clarified. In contrast more evidence indicates that vitamin B6 can protect from diabetes complications through its role as scavenger of AGEs. It has been demonstrated that in diabetes AGEs can destroy the functionality of macromolecules such as protein, lipids, and DNA, thus producing tissue damage that result in vascular diseases. AGEs can be in part also responsible for the increased cancer risk associated with diabetes. In this chapter the relationship between vitamin B6, diabetes and AGEs will be discussed by showing the acquired knowledge and questions that are still open.

One-Carbon Metabolism Nutrients, Genetic Variation, and Diabetes Mellitus

Diabetes mellitus (DM) affects about 9.3% of the population globally. Hyperhomocysteinemia (HHcy) has been implicated in the pathogenesis of DM, owing to its promotion of oxidative stress, β-cell dysfunction, and insulin resistance. HHcy can result from low status of one-carbon metabolism (OCM) nutrients (e.g., folate, choline, betaine, vitamin B6, B12), which work together to degrade homocysteine by methylation. The etiology of HHcy may also involve genetic variation encoding key enzymes in OCM. This review aimed to provide an overview of the existing literature assessing the link between OCM nutrients status, related genetic factors, and incident DM. We also discussed possible mechanisms underlying the role of OCM in DM development and provided recommendations for future research and practice. Even though the available evidence remains inconsistent, some studies support the potential beneficial effects of intakes or blood levels of OCM nutrients on DM development. Moreover, certain variants in OCM-related genes may influence metabolic handling of methyl-donors and presumably incidental DM. Future studies are warranted to establish the causal inference between OCM and DM and examine the interaction of OCM nutrients and genetic factors with DM development, which will inform the personalized recommendations for OCM nutrients intakes on DM prevention.

Biological Pathways Associated with Vitamins in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is characterized by early-appearing social communication deficits, with genetic and environmental factors potentially playing a role in its etiology, which remains largely unknown. During pregnancy, certain deficiencies in critical nutrients are mainly associated with central nervous system impairment. The vitamin B9 (folate) is primarily related to one-carbon and methionine metabolism, participating in methyl donor generation. In addition, supplementation with folic acid (FA) is recommended by the World Health Organization (WHO) in the first three gestational months to prevent neural tube defects. Vitamin B12 is related to folate regeneration, converting it into an active form. Deficiencies in this vitamin have a negative impact on cognitive function and brain development since it is involved in myelin synthesis. Vitamin D is intimately associated with Ca2+ levels, acting in bone development and calcium-dependent signaling. This vitamin is associated with ASD at several levels since it has a relation with ASD genes and oxidative stress environment. This review carries the recent literature about the role of folate, vitamin B12, and vitamin D in ASD. In addition, we discuss the possible impact of nutrient deficiency or hypersupplementation during fetal development. On the other hand, we explore the biases of vitamin supplementation studies such as the loss of participants in retrospective studies, as well as multiple variants that are not considered in the conclusion, like dietary intake or auto-medication during pregnancy. In this regard, we aim to contribute to the discussion about the role of vitamins in ASD currency, but also in pregnancy and fetal development as well. Furthermore, stress during pregnancy can be an ASD predisposition, with cortisol as a regulator. In this view, we propose that cortisol is the bridge of susceptibility between vitamin disorders and ASD prevalence.

A Narrative Review on Strategies for the Reversion of Prediabetes to Normoglycemia: Food Pyramid, Physical Activity, and Self-Monitoring Innovative Glucose Devices

In 2019, "Nutrition Therapy for Adults with Diabetes or Prediabetes: A Consensus Report" was published. This consensus report, however, did not provide an easy way to illustrate to subjects with prediabetes (SwPs) how to follow a correct dietary approach. The purpose of this review is to evaluate current evidence on optimum dietary treatment of SwPs and to provide a food pyramid for this population. The pyramid built shows that everyday consumption should consist of: whole-grain bread or potatoes eaten with their skins (for fiber and magnesium) and low glycemic index carbohydrates (GI < 55%) (three portions); fruit and vegetables (5 portions), in particular, green leafy vegetables (for fiber, magnesium, and polyphenols); EVO oil (almost 8 g); nuts (30 g, in particular, pistachios and almonds); three portions of dairy products (milk/yogurt: 300-400 g/day); mineral water (almost 1, 5 L/day for calcium intake); one glass of wine (125 mL); and three cups of coffee. Weekly portions should include fish (four portions), white meat (two portions), protein plant-based food (four portions), eggs (egg portions), and red/processed meats (once/week). At the top of the pyramid, there are two pennants: a green one means that SwPs need some personalized supplementation (if daily requirements cannot be satisfied through diet, vitamin D, omega-3, and vitamin B supplements), and a red one means there are some foods and factors that are banned (simple sugar, refined carbohydrates, and a sedentary lifestyle). Three to four times a week of aerobic and resistance exercises must be performed for 30-40 min. Finally, self-monitoring innovative salivary glucose devices could contribute to the reversion of prediabetes to normoglycemia.

Maternal folate and metabolic programming of the offspring: A systematic review of the literature

There is emerging evidence suggesting that folate status during pregnancy may play a role in fetal programming of metabolic disease. Therefore, this systematic review aims to summarize and systematize the current evidence surrounding the relationship between maternal folate status during pregnancy and offspring metabolic programming, focusing on both animal and human studies. PubMed, Web of Science and Scopus databases were searched in order to identify studies conducted on pregnant women or in animals studying the association between maternal folate exposure and at least one metabolic syndrome outcome in offspring after birth (weight, blood pressure, glucose regulation parameters, triglycerides and high-density lipoprotein cholesterol (HDL-C) levels). The quality of included studies was assessed using SYRCLE Risk of Bias Tools for animal studies and NHLBI Study Quality Assessment Tools for observational studies and randomized controlled trials. Among the 10 "good" or "fair" studies that investigated excessive folate exposure during the perigestational period, 7 animal studies and 1 human study reported a positive association with development of metabolic outcomes in offspring. On the other hand, 6 of the 7 "good" or "fair" included human studies compared adequate versus low folate exposure, showing a lack of association (n = 3) or a protective effect (n = 3) regarding offspring's dysmetabolism. In conclusion, there is strong evidence from animal trials suggesting that excessive folate intake in early phases of development programs for metabolic dysfunction. While human evidence regarding excessive maternal folate exposure is currently scarce, human studies suggest that folate adequacy in pregnancy is not detrimental for metabolic function of the offspring.

Associations Between Serum Folate Level and HOMA-IR in Chinese Patients with Type 2 Diabetes Mellitus

Background

Adequate intake of folic acid (FA) has been proven essential for metabolism, cellular homeostasis, and antioxidant effects in diabetic patients. Our aim was to evaluate the association between serum folate levels and the risk of insulin resistance in patients with type 2 diabetes mellitus (T2DM) and to provide new ideas and approaches for reducing the risk of T2DM.

Methods

This was a case-control study involving 412 participants (206 with T2DM). Anthropometric parameters, islet function, biochemical parameters and body composition of T2DM group and control group were determined. Correlation analysis and logistic regression were used to evaluate the risk factors associated with the onset of insulin resistance in T2DM.

Results

The folate levels in type 2 diabetic patients with insulin resistance were significantly lower than those in patients without insulin resistance. Logistic regression showed that FA and high-density lipoprotein were independent influencing factors for insulin resistance in diabetic patients (P < 0.05). After adjusting for confounding factors, the degree of insulin resistance in diabetic patients was in a significant inverse relationship with folate levels (P< 0.05). We also found that below the serum FA threshold of 7.09 ng/mL insulin resistance was significantly more elevated.

Conclusion

Our findings suggest that the risk of insulin resistance increases with the decrease in serum FA levels in T2DM patients. Monitoring folate levels in these patients and FA supplementation are warranted preventive measures.

Dietary patterns explaining variations in blood biomarkers in young adults are associated with the 30-year predicted cardiovascular disease risks in midlife: A follow-up study

BACKGROUND AND AIMS

To examine a combined effect of dietary intakes, blood lipid and insulin resistance in young adulthood on the risk of predicted CVD through midlife.

METHODS AND RESULTS

Data of young adults from a birth cohort study in Australia were used. Reduced rank regression (RRR) and partial least squares (PLS) methods identified dietary patterns rich in meats, refined grains, processed and fried foods, and high-fat dairy and low in whole grains and low-fat dairy from dietary intakes obtained at 21-years, and blood lipids and measures of insulin resistance measured at 30-years of age. Using standard CVD risk factors measured at 30-years of age, the Framingham Heart Study risk-prediction algorithms were used to calculate the 30-year predicted Framingham CVD risk scores. The scores represent Hard CVD events; coronary death, myocardial infarction and stroke and Full CVD events; Hard CVD plus coronary insufficiency and angina pectoris, transient ischaemic attack, intermittent claudication, and congestive heart failure in midlife. Sex-specific upper quartiles of CVD risk scores were used to define high-risk groups. Modified Poisson regression models were used to estimate relative risks (RRs) with 95% CI. Greater adherence to the diet identified applying RRR in young adulthood was associated with higher risks of predicted Hard CVD (RR: 1.60; 1.14, 2.25) and Full CVD (RR: 1.46; 1.04, 2.05) events in midlife. The diet from PLS showed similar trend of association for the risk of predicted Hard CVD events (RR: 1.49; 1.03, 2.16) in adjusted models.

CONCLUSION

Dietary patterns associated with variations in blood lipids and insulin resistance in young adulthood are associated with increased risks of predicted CVD events in midlife. The findings suggest that diet induced altered blood lipids and insulin resistance in the life course of young adulthood could increase the risks of CVD events in later life.

Daily folate consumption is associated with reduced all-cause and cardiovascular disease mortality among US adults with diabetes, prediabetes, or insulin resistance

We hypothesized that daily folate consumption may have a beneficial effect on mortality among adults with dysglycemia. This prospective cohort study was conducted on 9266, 12,601, and 16,025 US adults with diabetes, prediabetes, and insulin resistance (IR; homeostasis model assessment of IR >2.6), respectively, from the National Health and Nutrition Examination Survey Ⅲ and 1999-2018. Daily folate consumption was obtained from dietary recall. All-cause, cardiovascular disease (CVD), and cancer mortality were obtained by linking to the National Death Index Mortality Data. During 117,746.00, 158,129.30, and 210,896.80 person-years of follow-up, 3356 (1053 CVD and 672 cancer), 3796 (1117 CVD and 854 cancer), and 4340 (1286 CVD and 928 cancer) deaths occurred among participants with diabetes, prediabetes, and IR, respectively. After multivariate adjustment, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 7.1% (hazard ratio [HR], 0.929; 95% confidence interval [CI], 0.914-0.945), 12.4% (HR, 0.886; 95% CI, 0.860-0.912), and 6.4% (HR, 0.936; 95% CI, 0.903-0.972) decreases in risk of all-cause, CVD, and cancer mortality, respectively, among participants with diabetes. Among participants with prediabetes, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 3.6% (HR, 0.964; 95% CI, 0.949-0.980), 7.8% (HR, 0.922; 95% CI, 0.895-0.949), and 3.6% (HR, 0.964; 95% CI, 0.932-0.997) decreases in risk of all-cause, CVD, and cancer mortality, respectively. Among participants with IR, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 5.7% (HR, 0.943; 95% CI, 0.929-0.956) and 9.0% (HR, 0.910; 95% CI, 0.885-0.933) decreases in risk of all-cause and CVD mortality, respectively. Increased daily folate consumption may be beneficial in reducing all-cause and CVD mortality of adults with dysglycemia. More research is needed to explore the underlying mechanisms.

Dose-response association between dietary folate and niacin intakes with diabetes among Chinese adults: a cross-sectional study

BACKGROUND

The aim of this study was to examine the relationship between dietary intake of folate and niacin and diabetes risk in Chinese adults.

METHODS

This is a cross-sectional study. Demographic and anthropometric data along with information on dietary intake of vitamins were collected, and eligible participants were recruited to complete the questionnaire. A binary logistic regression analysis was conducted to examine the association between dietary intake of vitamins and diabetes risk, with adjustment for potential confounders. Non-linear dose-response relationships between dietary intake of folate and niacin and diabetes risk were also evaluated using adjusted restricted cubic splines.

RESULTS

Of the 3106 eligible participants, 15.9% had diabetes. Median folate was significantly higher in diabetic patients than in controls (32.030 vs. 27.600 gμ), while median niacin was significantly lower (7.000 vs. 7.900 mg). After controlling for potential confounders, binary logistic regression analysis showed that each unit increase in folate intake was associated with a 1.002-fold increase in the risk of developing diabetes (odds ratio (OR) = 1.002; 95% confidence interval (CI) 1.000-1.004; P = 0.022), while each unit increase in niacin intake was associated with a 3.5% reduction in diabetes risk (OR = 0.965; 95% CI 0.944-0.986; P = 0.001). The plots of restricted cubic splines presented an atypical inverted U-shaped association between dietary intake of folate and diabetes risk.

CONCLUSIONS

Diabetic patients had a low intake of vitamins, especially the B vitamins. Dietary intake of folate and niacin tended to be independently associated with the risk of diabetes. Nevertheless, this study is observational and a large-scale randomized controlled trial is yet to be conducted, which will add to the evidence of the study results.

Folate, Vitamin B6, and Vitamin B12 Status in Association With Metabolic Syndrome Incidence

IMPORTANCE

The associations of B vitamin status with metabolic syndrome (MetS) incidence among the US population remain unclear.

OBJECTIVE

To investigate intakes and serum concentrations of folate, vitamin B6, and vitamin B12 in association with MetS risk in a large US cohort.

DESIGN, SETTING, AND PARTICIPANTS

This prospective study included Black and White young adults in the US who were enrolled from 1985 to 1986 and studied until 2015 to 2016. Diet was assessed using a validated diet history at examination years 0, 7, and 20. Serum concentrations of folate, vitamin B6, and vitamin B12 were assayed at examination years 0, 7, and 15 in a subset of 1430 participants. MetS was ascertained by clinic and laboratory measurements and self-reported medication use. Data were analyzed between January and July 2021.

EXPOSURES

Intakes and serum levels of folate, vitamin B6, and vitamin B12.

MAIN OUTCOMES AND MEASURES

Multivariable Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% CIs for the associations of energy-adjusted B vitamin intakes or serum B vitamin levels with incident MetS.

RESULTS

The study included 4414 participants, with 2225 Black individuals (50.4%) and 2331 women (52.8%). The mean (SD) age at baseline was 24.9 (3.6) years. A total of 1240 incident MetS cases occurred during the 30 years (mean [SD], 22.1 [9.5] years) of follow-up. Compared with the lowest quintile of each energy-adjusted B vitamin intake, the HRs for incident MetS in the highest quintile were 0.39 (95% CI, 0.31-0.49) for folate (P for trend < .001), 0.61 (95% CI, 0.46-0.81) for vitamin B6 (P for trend = .002), and 0.74 (95% CI, 0.58-0.95) for vitamin B12 (P for trend = .008) after adjustment for potential confounders. Similarly, significant inverse associations were observed in the subset with serum data on these B vitamins (folate: HR, 0.23; 95% CI, 0.17-0.33; P for trend < .001; vitamin B6: HR, 0.48; 95% CI, 0.34-0.67; P for trend < .001; and vitamin B12: HR, 0.70; 95% CI, 0.51-0.96; P for trend = .01).

CONCLUSIONS AND RELEVANCE

This prospective cohort study found that intakes and serum concentrations of folate, vitamin B6, and vitamin B12 were inversely associated with incident MetS among Black and White young adults in the US.

Associations of Telomere Length and Change With Cognitive Decline Were Modified by Sex and Race: The REGARDS Study

INTRODUCTION

We examined the associations of baseline telomere length (TL) and TL change with cognitive function over time in older US adults, as well as differences by sex and race.

METHODS

A total of 1820 cognitively healthy individuals (median baseline age: 63 years) were included. Telomere length was measured using qPCR-based method at baseline and among 614 participants in the follow-up examination 10 years later. Cognitive function was assessed by a four-test battery every 2 years.

RESULTS

In multivariable-adjusted linear mixed models, longer baseline TL and smaller attrition/lengthening of TL over time were associated with better Animal Fluency Test score. Longer baseline TL was also linearly associated with better Letter Fluency Test score. The observed associations were consistently more pronounced in women than men and in Black compared to White participants.

DISCUSSION

Telomere length may be a biomarker that predicts long-term verbal fluency and executive function, particularly in women and Black Americans.

The Association between Maternal B Vitamins in Early Pregnancy and Gestational Diabetes Mellitus: A Prospective Cohort Study

Background: This study evaluated the association between maternal B vitamins in early pregnancy and gestational diabetes mellitus (GDM) risk. Methods: A cohort of 1265 pregnant women was recruited at 8−15 weeks of gestation in 2021−2022 (Shanghai, China). Pregnancies with both serum B vitamin measurements at recruitment and glucose measurements at 24−28 weeks of gestation were included in the final analysis. Results: Of the 1065 pregnancies, in the final analysis, GDM occurred in 121 women (11.36%). In multivariate logistic models, an increased risk trend across serum vitamin B1 quartiles with GDM was observed (p-Trend = 0.001). Compared with women in the lowest quartile of serum vitamin B6, those in the upper two quartiles had approximately twofold higher odds of GDM. Moreover, compared with women with vitamin B12 levels < 150 pmol/L, those with vitamin B12 levels > 150 pmol/L had lower odds of GDM (p = 0.005). The restricted cubic spline regression models also revealed that serum vitamin B6 and vitamin B12 were associated with an increased risk of GDM in a nonlinear fashion. Conclusions: Our study shows that higher maternal serum vitamin B1 and B6 levels in early pregnancy are associated with increased GDM risk, while sufficient vitamin B12 status is associated with lower GDM risk.

Flavin Adenine Dinucleotide (FAD) and Pyridoxal 5'-Phosphate (PLP) Bind to Sox9 and Alter the Expression of Key Pancreatic Progenitor Transcription Factors

Cofactor flavin adenine dinucleotide (FAD), a compound with flavin moiety and a derivative of riboflavin (vitamin B₂), is shown to bind to Sox9 (a key transcription factor in early pancreatic development) and, subsequently, induce a large increase in markers of pancreatic development, including Ngn3 and PTF1a. Pyridoxal 5'-phosphate (PLP), the active form of vitamin B₆, also binds to Sox9 and results in a similar increase in pancreatic development markers. Sox9 is known to be specifically important for pancreatic progenitors. Previously, there was no known link between FAD, PLP, or other co-factors and Sox9 for function. Thus, our findings show the mechanism by which FAD and PLP interact with Sox9 and result in the altered expression of pancreatic progenitor transcription factors involved in the pancreas development.

Circulating homocysteine and folate concentrations and risk of type 2 diabetes: A retrospective observational study in Chinese adults and a Mendelian randomization analysis

Background

The relation between circulating homocysteine (hcy) and folate concentrations and risk of type 2 diabetes mellitus (T2DM) has been evaluated in several observational studies with inconsistent results; and it is unclear about their causal relationships. Our aim was to assess the causality association between circulating hcy or folate concentrations and the development of T2DM using Mendelian randomization (MR) analysis, based on results of an observational study in Chinese adults.

Methods

We conducted an observational study of 370 patients with T2DM and 402 controls after routine physical examination who consulted at the Zhongnan Hospital of Wuhan University between March 2021 and December 2021. Correlations between hcy and folate and the incidence of T2DM were quantified using logistic regression models. Two-sample MR analysis was conducted using summary statistics of genetic variants gained from 2 genome-wide association studies (GWAS) on circulating hcy and folate concentrations in individuals of European ancestry and from an independent GWAS study based on DIAMANTE meta-analysis.

Results

In the observational study, after logistic regression with multiple adjustment, lower hcy and higher folate levels were identified to be associated with the risk of T2DM, with OR (95% CI) for hcy of 1.032 (1.003–1.060); while 0.909 (0.840–0.983) for folate. In the MR analysis, the OR for T2DM was 1.08 (95% CI: 0.95, 1.21; P = 0.249) for each SD unit increase in genetically predicted homocysteinemia and the OR for T2DM per SD increase in genetically predicted folate elevation was 0.80 (95% CI: 0.60, 1.00, P = 0.026).

Conclusions

We discovered that high circulating hcy and low folate concentrations were related with an increased risk of developing T2DM in Chinese adults. Moreover, MR analysis provided genetic evidence for a possible causal relationship between serum folate and the risk of T2DM.

Vitamin B6 Inhibits High Glucose-Induced Islet β Cell Apoptosis by Upregulating Autophagy

Vitamin B6 may alleviate diabetes by regulating insulin secretion and increasing insulin sensitivity, but its mechanism remains to be explored. In this study, vitamin B6-mediated autophagy and high glucose-induced apoptosis were tested to investigate the mechanism by which vitamin B6 regulates insulin release. The results showed that 20 mM glucose increased the apoptosis rate from 10.39% to 22.44%. Vitamin B6 reduced the apoptosis rate of RIN-m5F cells from 22.44% to 11.31%. Our data also showed that the vitamin B6 content in processed eggs was decreased and that the hydrothermal process did not affect the bioactivity of vitamin B6. Vitamin B6 increased the number of autophagosomes and the ratio of autophagosome marker protein microtubule associated protein 1 light chain 3 beta to microtubule associated protein 1 light chain 3 alpha (LC3-II/LC3-I). It also decreased the amount of sequetosome 1 (SQSTM1/p62) and inhibited the phosphorylation of p70 ribosomal protein S6 kinase (p70S6K) under normal and high glucose stress. Another study showed that vitamin B6 inhibited the apoptosis rate, whereas the autophagy inhibitor 3-methyladenine (3-MA) blocked the protective effect of vitamin B6 against apoptosis induced by high glucose. The hydrothermal process decreased the vitamin B6 content in eggs but had no effect on the cytoprotective function of vitamin B6 in RIN-m5f cells. In conclusion, we demonstrated that vitamin B6-mediated autophagy protected RIN-m5f cells from high glucose-induced apoptosis might via the mTOR-dependent pathway. Our data also suggest that low temperatures and short-term hydrothermal processes are beneficial for dietary eggs.

Associations of folate intake with all-cause and cause-specific mortality among individuals with diabetes

Background and aims

The evidence regarding folate intake and mortality risk among patients with type 2 diabetes (T2D) remains unclear. This study aimed to investigate the association of folate intake with the risk of mortality among individuals with T2D.

Methods

A total of 9,196 participants with T2D from the Third National Health and Nutrition Examination Survey (NHANES III) and NHANES 1999–2014 were included. The data of survival were obtained by the cohort database linked with the national death index up to 31 December 2015. The Cox proportional hazard model was used to evaluate the relationship between dietary folate with all-cause and cause-specific mortality.

Results

Among patients with T2D, dietary folate intake was negatively correlated with all-cause mortality, cardiovascular mortality, and cancer mortality in men, and for women with all-cause mortality and cardiovascular mortality. The multivariate adjustment hazard ratio (HR) (95% CIs) for men of highest vs. lowest quartile was 0.77 (0.66–0.90), 0.61 (0.45–0.83), and 0.70 (0.49–0.99) for all-cause, cardiovascular, and cancer mortality, respectively. Among women, the multivariate adjustment HR (95% CIs) of highest vs. lowest quartile was 0.77 (0.64–0.92), 0.52 (0.33–0.83), and 0.78 (0.50–1.22) for all-cause, cardiovascular, and cancer mortality, respectively.

Conclusion

Higher dietary intake of folate was significantly associated with lower all-cause and cardiovascular mortality. This cohort study suggested that increasing the dietary folate intake may reduce mortality risk among U.S. adults with T2D.

Association between dietary intake of one-carbon metabolism nutrients and hyperglycemia in coal-burning fluorosis areas of Guizhou, China

Background and aims

There are limited studies describing the association between dietary intake of one-carbon metabolism nutrients and hyperglycemia. The present study aimed to investigate the association of habitual dietary intake of one-carbon metabolism nutrients with hyperglycemia in a fluorosis area in China, and explored the interaction between these nutrients and fluorosis related to hyperglycemia.

Method

In a cross-sectional study, we recruited 901 villagers, ages ranging from 18–75, in Guizhou Province. Dietary data and other covariate data were obtained through an interviewer-administered questionnaire. We collected venous blood samples from participants who had fasted for one night to obtain fasting blood glucose levels and we categorized dietary intake of betaine, total choline, methionine, folate, vitamins B₆ and B₁₂, and choline subclasses into quartiles (Q1–Q4). The lowest quartile (Q1) served as the reference group. An unconditional logistic regression model was used to evaluate the protective effects of a dietary intake of one-carbon nutrients against hyperglycemia. We calculated Odds Ratios (ORs) with 95% confidence intervals (CIs). A presence or absence of fluorosis subgroup analysis was performed to determine the potential effect of fluorosis on hyperglycemia.

Result

After adjusting for potential confounding factors, we found that a greater intake of dietary vitamin B₆, total choline and methyl-donor index was inversely associated with the occurrence of hyperglycemia (P-trend <0.05). However, there were no significant associations between hyperglycemia and the dietary intake of folate, vitamin B₁₂, methionine, and betaine. As for the choline subgroups, it showed that the dietary intake of free choline, phosphatidylcholine, and glycerol phosphatidylcholine was negatively correlated with the occurrence of hyperglycemia (P < 0.05). In contrast, there was no statistical association between dietary phosphatidylcholine and sphingomyelin and hyperglycemia (all P > 0.05). The results of subgroup analysis showed that dietary intake of folate, vitamin B₆, total choline, free choline, glycerol phosphorylcholine, and phosphocholine had a protective effect against the occurrence of hyperglycemia in the non-fluorosis subgroup, although no effects were observed in the fluorosis subgroup. There were significant interactions between these nutrients and fluorosis (P = 0.010–0.048).

Conclusion

The study demonstrated that higher dietary intake of vitamin B₆, total choline, methyl-donor index, free choline, glycerol phosphorylcholine, and phosphocholine in choline compounds were associated with a lower incidence of hyperglycemia. Moreover, the associations were modified by the presence or absence of fluorosis. Further investigation is needed to test the association in large-scale follow-up studies.

Association of Homocysteine Levels With Medial Temporal Lobe Atrophy Among Carriers and Non-carriers of APOE ε4 in MCI Subjects

Background

Different clinical subtypes of mild cognitive impairment (MCI) involve heterogeneous underlying etiologies. This study investigated the association between demographics, neuropsychological performance, apolipoprotein E (APOE) genotype and magnetic resonance imaging (MRI) measures in patients with MCI (amnestic [aMCI] and non-amnestic [naMCI]).

Methods

This case-control study included 130 aMCI patients, 58 naMCI patients, and 1,106 healthy controls (HCs). APOE genotypes, medial temporal lobe atrophy (MTA), neurological evaluation results, and white matter hyperintensities (WMH) were investigated. Serum folate and vitamin B12 concentrations were analyzed by radioimmunoassay, and plasma hyperhomocysteinemia (Hcy) was assessed by a high-performance liquid chromatography-fluorescence method.

Results

Serum folate levels were significantly lower, but plasma Hcy levels were higher, in patients with aMCI and naMCI than in healthy controls. There were significantly higher MTA scores in the aMCI group than the healthy control group. Multiple linear regression showed that serum Hcy and folate concentrations were positively associated with MTA (p < 0.05), while APOE4 showed a significant negative association with MTA in the aMCI group (p < 0.01). In addition, moderate/severe WMH showed a significant negative association with MTA in the naMCI and HC groups (p < 0.01).

Conclusion

The combined presence of APOE4 and Hcy is associated with aMCI in elderly individuals, while moderate/severe WMH is related to naMCI, which suggests etiological differences across MCI subtypes.

Associations of Serum Folate and Vitamin B12 Levels With Cardiovascular Disease Mortality Among Patients With Type 2 Diabetes

Importance

The associations of serum folate and vitamin B12 levels with cardiovascular outcomes among patients with type 2 diabetes (T2D) remain unclear.

Objective

To investigate the associations of serum folate and vitamin B12 levels with risk of cardiovascular disease (CVD) mortality among individuals with T2D.

Design, Setting, and Participants

This prospective cohort study included 8067 patients with T2D who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2014 and NHANES III (1988-1994). American Diabetes Association criteria were used to define T2D. Data were analyzed between October 1, 2020, and April 1, 2021.

Exposures

Serum folate and vitamin B12 levels.

Main Outcomes and Measures

Multivariable Cox proportional hazards regression models were used to compute hazard ratios and 95% CIs for the associations of serum folate and vitamin B12 levels with risks of CVD and all-cause mortality. Two multivariable models were constructed. Restricted cubic spline analyses were used to examine the nonlinear association of serum folate levels and vitamin B12 levels with CVD mortality, and nonlinearity was assessed using the likelihood ratio test.

Results

This cohort study included data from 7700 participants in the folate analysis (mean [SE] age, 57.8 [0.3] years; 3882 men [weighted, 50.5%]; median serum folate level, 12.1 ng/mL [IQR, 7.1-19.5 ng/mL]) and 4860 participants for the vitamin B12 analysis (mean [SE] age, 57.8 [0.3] years; 2390 men [weighted, 50.7%]; median serum vitamin B12 level, 506.1 pg/mL [IQR, 369.1-703.5 pg/mL]). During 72 031 person-years of follow-up, 799 CVD deaths were documented for the folate analysis, and during 43 855 person-years of follow-up, 467 CVD deaths were reported for the vitamin B12 analysis. Nonlinear associations were observed for serum levels of folate (P = .04 for nonlinearity) and vitamin B12 (P = .04 for nonlinearity) with risk of CVD mortality among patients with T2D. Compared with participants in the second quartile of serum folate levels (7.1-12.1 ng/mL), the hazard ratios for CVD mortality were 1.43 (95% CI, 1.04-1.98) for participants in the lowest serum folate level quartile (<7.1 ng/mL) and 1.03 (95% CI, 0.74-1.44) for participants in the highest quartile (≥19.5 ng/mL). In addition, compared with participants in the second quartile of serum vitamin B12 levels (369.1-506.0 pg/mL), the hazard ratios for CVD mortality were 1.74 (95% CI, 1.20-2.52) for participants in the lowest quartile (<369.1 pg/mL) and 2.32 (95% CI, 1.60-3.35) for participants in the highest quartile (≥703.5 pg/mL). Similar patterns of association were observed for all-cause mortality (nonlinearity: P = .01 for folate and P = .02 for vitamin B12).

Conclusions and Relevance

This cohort study found that both low and high serum levels of vitamin B12 as well as low serum levels of folate were significantly associated with higher risk of CVD mortality among individuals with T2D.

Nutrients and Dietary Approaches in Patients with Type 2 Diabetes Mellitus and Cardiovascular Disease: A Narrative Review

Cardiovascular disease (CVD) is the most common cause of morbidity and mortality in developed countries. The prevalence of CVD is much higher in patients with type 2 diabetes mellitus (T2DM), who may benefit from lifestyle changes, which include adapted diets. In this review, we provide the role of different groups of nutrients in patients with T2DM and CVD, as well as dietary approaches that have been associated with better and worse outcomes in those patients. Many different diets and supplements have proved to be beneficial in T2DM and CVD, but further studies, guidelines, and dietary recommendations are particularly required for patients with both diseases.