Effect of folate supplementation on insulin sensitivity and type 2 diabetes: a meta-analysis of randomized controlled trials

Downregulation of NAD Kinase Expression in β-Cells Contributes to the Aging-Associated Decline in Glucose-Stimulated Insulin Secretion

Nicotinamide adenine dinucleotide kinase (NADK) is essential to the generation of nicotinamide adenine dinucleotide phosphate (NADP(H)), an important metabolic coupling factor involved in glucose-stimulated insulin secretion. In the present study, we showed that the expression of Nadk and Nadk2 transcripts and NADP(H) content were lower in islets of 80-week-old (aged) mice than those of 8-week-old (young) mice. This was associated with diminished oral glucose tolerance of old mice and the glucose-stimulated insulin secretion (GSIS) response of islets. Knockdown (KD) of Nadk or Nadk2 gene expression in NIT-1 cells impaired glucose-stimulated insulin secretion. Metabolomic analysis revealed that Nadk KD specifically affected purine metabolism in glucose-stimulated cells. The levels of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) were higher in KD cells than in the non-targeting control (NTC) cells. Phosphorylation of AMP-activated protein kinase (AMPK) was elevated in glucose-treated KD cells compared to that of NTC cells. Increased AICAR level and AMPKα phosphorylation were observed in the glucose-stimulated islets of the aged mice. Genetic and pharmacological inhibition of AMPK promoted glucose-stimulated insulin release by KD cells and the aged mouse islets. It is likely that NADK is modulatory to AMPK activation in pancreatic β-cells and to their GSIS response. Enhanced AICAR formation in KD cells was accompanied by significantly increased conversion from inosine monophosphate (IMP) in a tetrahydrofolate (THF)-dependent manner. Folate supplementation augmented the GSIS response of KD cells and aged mouse islets. Taken together, these findings suggest that the aging-associated decline in NADK expression may underlie the reduced insulin secretory capacity of pancreatic β-cells.

Synergistically effects of n-3 PUFA and B vitamins prevent diabetic cognitive dysfunction through promoting TET2-mediated active DNA demethylation

Diabetic cognitive dysfunction (DCD) refers to the cognitive impairment observed in individuals with diabetes. Epidemiological studies have suggested that supplementation with n-3 polyunsaturated fatty acid (PUFA) or B vitamins may prevent the development of diabetic complications. Post hoc studies indicate a potential synergistic effect of n-3 PUFA and B vitamins in preventing cognitive impairment. However, the precise effect and underlying mechanism of this combination on DCD remain unclear. In case-control study, we compared fatty acid composition of erythrocyte membrane and serum homocysteine levels between diabetic individuals with and without DCD. We found that insufficient levels of n-3 PUFA, along with elevated serum homocysteine, significantly increase the risk of developing DCD. Treatment with a combination of fish oil, folate, and vitamin B12 improved cognitive impairment and aberrant neuronal morphology in streptozotocin-induced DCD mice. Folic acid and vitamin B12 enhanced the efficiency of exogenous docosahexaenoic acid (DHA) transportation to the brain by preventing the accumulation of homocysteine and S-adenosylhomocysteine, thereby inhibiting neuronal apoptosis in diabetic brains. Furthermore, folic acid and vitamin B12 supplementation can provide sufficient 5-methylcytosine for diabetic brains by promoting DNA methylation, while increased DHA levels maintain TET-mediated active DNA demethylation in diabetic brains through enhancing TET2 function. Overall, our study provides novel insights into molecular mechanisms underlying the synergistic preventive effects of the combined supplementation with fish oil, folic acid and vitamin B12 on DCD, suggests that combining n-3 PUFA and B vitamins could be a promising strategy for preventing DCD among individuals with diabetes.

Folic Acid as a Potential Vitamin in Glycemic Control: A Systematic Review

PURPOSE

This systematic review aims to examine the relationship between serum folate level and folic acid supplements with glycemic control parameters (fasting blood glucose (FBG), insulin level, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and Hemoglobin A1C (HbA1c)) in adult individuals with current studies.

METHODS

In this study, which was designed as a systematic review, the searches were performed on Web of Science, Science Direct, Medline, Wiley, and Cochrane Library databases between April 10, 2023, and May 10, 2023, and the searches were updated between October 16, 2023, and November 14, 2023. Of the 1855 studies obtained from the screening, 17 met the criteria and were included in the systematic review. The PROSPERO system registered the study protocol (ID: CRD42023472434).

RECENT FINDINGS

Although no significant correlation was found between serum folate levels and glycemic control parameters in most of the cross-sectional studies included in this systematic review, most of the randomized controlled trials showed that glycemic control parameters (FBG, insulin, HOMA-IR) decreased significantly in the intervention group receiving folic acid supplementation compared to the control group. However, study durations were short, and HbA1c needed to be evaluated in most studies. This makes it difficult to get information about the long-term effects of folic acid supplementation. More comprehensive studies should be conducted to draw more precise conclusions about the relationship between folic acid levels and folic acid supplementation with glycemic control parameters.

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

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

[Polycystic ovary syndrome: new and promising treatment methods]

Polycystic Ovary Syndrome (PCOS) - is a polygenic endocrine disorder caused by genetic, hormonal, and epigenetic factors. The importance of addressing PCOS lies in its prevalence, affecting approximately 10 to 13% of women, as well as the associated health conditions that can have a negative impact on women's lives, including infertility, dermatological manifestations of hyperandrogenism (such as hirsutism and acne), cardiovascular pathologies, metabolic disorders, and psychoemotional disorders. Currently, many theories of the development of this disease have been proposed, and as a consequence of methods of influencing and treating it. According to the clinical recommendations of the Ministry of Health of the Russian Federation, modifying the patient's lifestyle forms the basis of comprehensive therapy. We have analyzed about 60 articles on various dietary approaches to the treatment of PCOS, sourced from PubMed, Nature Reviews, Oxford Academic, Clinical Nutrition, EJOG, ScienceDirect, and MDPI. The Mediterranean diet, the DASH diet, the ketogenic diet and the low-carb diet have proven themselves the best. Also, it's necessary to add vitamin D, E, folic acid, calcium, various pro- and prebiotics to a woman's diet. Currently, the use of inositol and GPP-1 is becoming a promising method of PCOS therapy. According to the results of the analysis, a positive effect of diet therapy on the anthropometric and biochemical parameters was noted. Based on the analysis, a positive effect of diet therapy on anthropometric and biochemical parameters has been observed. It is crucial to consider the individual characteristics of each patient and not rely solely on drug therapy when approaching the treatment of PCOS.

Folic acid supplementation on inflammation and homocysteine in type 2 diabetes mellitus: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The beneficial effects of folate have been observed under different conditions, but the available evidence on inflammation and reduction of cardiovascular disease (CVD) in type 2 diabetes mellitus (T2DM) is limited. The study aimed to explore the effects of folate on inflammation and homocysteine amongst individuals with T2DM.

METHODS

PubMed, Scopus, and Cochrane Library were used to search for evidence. A random-effect model meta-analysis through Review Manager (version 5.4) and metaHun was performed. Results were reported as standardized mean differences (SMD) and 95% confidence intervals graphically using forest and funnel plots.

RESULTS

Data from 9 trials with 426 patients living with T2DM were analyzed. Folic acid supplementation significantly revealed a large effect size on homocysteine levels compared to placebo, SMD = -1.53, 95%CI (-2.14,-0.93), p < 0.05. Additionally, we observed a medium marginal effect size on C-reactive protein (SMD = -0.68, 95%CI (-1.34, -0.01), p = 0.05). However, no significant effect on tumor necrosis factor-α (SMD = -0.86, 95%CI (-2.65, 0.93), p = 0.34), and interleukin-6 (SMD = -0.04, 95%CI (-1.08, 1.01), p = 0.95) was observed.

CONCLUSION

Evidence analyzed in this study suggests that folic acid supplementation in T2DM reduces homocysteine and may mitigate CVDs. However, its effect on inflammation is inconclusive.

Intake of different types of seafood and meat and risk of type 2 diabetes in women: a prospective study supported by a dietary intervention in mice

Detailed knowledge regarding the associations between intake of different types of seafood and meat and the risk of type 2 diabetes (T2D), and insight into possible mechanisms are warranted. In this study we aimed to evaluate the associations between intake of different types of seafood and meat and the subsequent risk of T2D using the Norwegian Mother, Father, and Child Cohort Study (MoBa), and furthermore, by using a mouse model to gain further insight into possible molecular mechanisms contributing to the associated metabolic changes. Women in MoBa who were free of pharmacologically treated diabetes at baseline (n = 60,777) were prospectively evaluated for incident T2D, identified on the basis of medication usages > 90 days after delivery, ascertained by the Norwegian Prescription Database. Dietary intake was obtained with a validated 255-item food frequency questionnaire which assessed habitual diet during the first 4-5 months of pregnancy. Metabolic phenotypes and plasma metabolome were investigated in female mice fed isocaloric diets with different types of seafood and meat mimicking the dietary intake in the human cohort. During maximum 10-year and mean (SD) 7.2 (1.6) years follow-up time, 681 (1.1%) women developed pharmacologically treated T2D. All statistical models identified a higher risk of T2D with increased shellfish intake, whereas no associations were observed for total seafood, fatty fish, total meat and red meat in the adjusted models. In mice, the shellfish-based western diet induced reduced glucose tolerance and insulin secretion compared to the diet based on lean fish, and we identified a number of metabolites elevated in plasma from shellfish-fed mice that correlated with glucose intolerance. Mice fed a western diet based on meat also exhibited reduced glucose tolerance in comparison to lean fish fed mice, whereas mice fed fatty fish, total seafood or red meat did not differ from lean fish fed mice. We observed a diet-specific metabolic signature in plasma demonstrating five distinct metabolite profiles in mice fed shellfish, fatty fish, total seafood/lean fish, a mixed diet and meat. In conclusion, these findings demonstrate that different types of seafood have different outcome on T2D risk. In women, intake of shellfish was associated with higher risk of T2D. In female mice, a shellfish enriched diet reduced glucose tolerance and altered the abundance of several distinct plasma metabolites correlating with glucose tolerance.

Protective Factors and the Pathogenesis of Complications in Diabetes

Chronic complications of diabetes are due to myriad disorders of numerous metabolic pathways that are responsible for most of the morbidity and mortality associated with the disease. Traditionally, diabetes complications are divided into those of microvascular and macrovascular origin. We suggest revising this antiquated classification into diabetes complications of vascular, parenchymal, and hybrid (both vascular and parenchymal) tissue origin, since the profile of diabetes complications ranges from those involving only vascular tissues to those involving mostly parenchymal organs. A major paradigm shift has occurred in recent years regarding the pathogenesis of diabetes complications, in which the focus has shifted from studies on risks to those on the interplay between risk and protective factors. While risk factors are clearly important for the development of chronic complications in diabetes, recent studies have established that protective factors are equally significant in modulating the development and severity of diabetes complications. These protective responses may help explain the differential severity of complications, and even the lack of pathologies, in some tissues. Nevertheless, despite the growing number of studies on this field, comprehensive reviews on protective factors and their mechanisms of action are not available. This review thus focused on the clinical, biochemical, and molecular mechanisms that support the idea of endogenous protective factors, and their roles in the initiation and progression of chronic complications in diabetes. In addition, this review also aimed to identify the main needs of this field for future studies.

A prospective association between dietary mushroom intake and the risk of type 2 diabetes: the Korean Genome and Epidemiology Study-Cardiovascular Disease Association Study

OBJECTIVES

Mushrooms, known for their nutritious and functional components, are considered healthy and medicinal. This study investigated the prospective association between dietary mushroom consumption and the incidence of type 2 diabetes among Korean adults aged ≥40 years.

METHODS

In total, 16,666 participants who were not taking anti-diabetic medication or insulin and had normal fasting blood glucose (FBG; <126 mg/dL) were included. We used the cumulative average dietary consumption of mushrooms as an exposure metric, calculated from food frequency questionnaires at every follow-up, along with covariates collected during a baseline survey. To estimate incidence rate ratios (IRRs) for type 2 diabetes, a modified Poisson regression model with a robust error estimator was applied.

RESULTS

In multivariable models, dietary mushroom consumption was inversely associated with type 2 diabetes incidence in both genders (men: IRR, 0.65; 95% confidence interval [CI], 0.47 to 0.90; plinearity=0.043 in the highest quartile (Q4) vs. the lowest quartile (Q1); women: IRR, 0.70; 95% CI, 0.54 to 0.93; plinearity=0.114 in Q4 vs. Q1). The inverse association remained after adjustment for dietary factors instead of dietary quality index, the baseline FBG, and the exclusion of incidence within the first year. Additionally, no significant interaction was found regarding the risk of type 2 diabetes between dietary mushroom consumption and participants' gender or other factors.

CONCLUSIONS

Dietary mushroom consumption was inversely linked with the risk of type 2 diabetes incidence in both genders, indicating the beneficial role of mushrooms in preventing the disease.

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.

A causal relationship between antioxidants, minerals and vitamins and metabolic syndrome traits: a Mendelian randomization study

BACKGROUND

The available evidence regarding the association of antioxidants, minerals, and vitamins with the risk of metabolic syndrome (MetS) traits is currently limited and inconsistent. Therefore, the purpose of this Mendelian randomization (MR) study was to investigate the potential causal relationship between genetically predicted antioxidants, minerals, and vitamins, and MetS.

METHODS

In this study, we utilized genetic variation as instrumental variable (IV) to capture exposure data related to commonly consumed dietary nutrients, including antioxidants (β-carotene, lycopene, and uric acid), minerals (copper, calcium, iron, magnesium, phosphorus, zinc, and selenium), and vitamins (folate, vitamin A, B6, B12, C, D, E, and K1). The outcomes of interest, namely MetS (n = 291,107), waist circumference (n = 462,166), hypertension (n = 463,010), fasting blood glucose (FBG) (n = 281,416), triglycerides (n = 441,016), and high-density lipoprotein cholesterol (HDL-C) (n = 403,943), were assessed using pooled data obtained from the most comprehensive genome-wide association study (GWAS) available. Finally, we applied the inverse variance weighting method as the result and conducted a sensitivity analysis for further validation.

RESULTS

Genetically predicted higher iron (OR = 1.070, 95% CI 1.037-1.105, P = 2.91E-05) and magnesium levels (OR = 1.130, 95% CI 1.058-1.208, P = 2.80E-04) were positively associated with increased risk of MetS. For each component of MetS, higher level of genetically predicted selenium (OR = 0.971, 95% CI 0.957-0.986, P = 1.09E-04) was negatively correlated with HDL-C levels, while vitamin K1 (OR = 1.023, 95% CI 1.012-1.033, P = 2.90E-05) was positively correlated with HDL-C levels. Moreover, genetically predicted vitamin D (OR = 0.985, 95% CI 0.978-0.992, P = 5.51E-5) had a protective effect on FBG levels. Genetically predicted iron level (OR = 1.043, 95% CI 1.022-1.064, P = 4.33E-05) had a risk effect on TG level.

CONCLUSIONS

Our study provides evidence that genetically predicted some specific, but not all, antioxidants, minerals, and vitamins may be causally related to the development of MetS traits.

Behavioral and biochemical investigations to explore the efficacy of quercetin and folacin in experimental diabetes induced vascular endothelium dysfunction and associated dementia in rats

OBJECTIVES

Vascular dementia (VaD), being strongly associated with metabolic conditions is a major health concern around the world. Diabetes is a major risk factor for the development of VaD. This study investigates the efficacy of quercetin and folacin in diabetes induced vascular endothelium dysfunction and related dementia.

METHODS

Single dose streptozotocin (STZ) (50 mg/kg i.p) was administered to albino Wistar rats (male, 200-250 g) by dissolving in citrate buffer. Morris water maze (MWM) and attentional set shifting tests were used to assess the spatial learning, memory, reversal learning, and executive functioning in animals. Body weight, serum glucose, serum nitrite/nitrate, vascular endothelial function, aortic superoxide anion, brains' oxidative markers (thiobarbituric acid reactive species-TBARS, reduced glutathione-GSH, superoxide dismutase-SOD, and catalase-CAT), mitochondrial enzyme complex (I, II, and IV), inflammatory markers (interleukin-IL-6, IL-10, tumor necrosis factor-TNF-α, and myeloperoxidase-MPO), and acetylcholinesterase activity-AChE were also assessed. Quercetin (30 mg kg-1/60 mg kg-1) and folacin (30 mg kg-1/60 mg kg-1) were used as the treatment drugs. Donepezil (0.5 mg kg-1) was used as a positive control.

RESULTS

STZ administered rats showed reduction in learning, memory, reversal learning, executive functioning, impairment in endothelial function, increase in brains' oxidative stress; inflammation; AChE activity, and decrease in mitochondrial complex (I, II, and IV) activity. Administration of quercetin and folacin in two different doses, significantly attenuated the STZ induced diabetes induced impairments in the behavioral, endothelial, and biochemical parameters.

CONCLUSIONS

STZ administration caused diabetes and VaD which was attenuated by the administration of quercetin and folacin. Therefore, these agents may be studied further for the assessment of their full potential in diabetes induced VaD conditions.

Folate deficiency may increase the risk for elevated TSH in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) and thyroid dysfunction (TD) are two common chronic endocrine disorders that often coexist. Folate deficiency has been reported to be related with the onset and development of T2DM. However, the relationship between folate deficiency and TD remains unclear. This study aims to investigate the association of serum folate with TD in patients with T2DM.

METHODS

The study used data on 268 inpatients with T2DM in the Beijing Chao-yang Hospital, Capital Medical University from October 2020 to February 2021. Thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), and serum folate were measured with chemiluminescence immunoassay (CLIA), and folate deficiency was defined as a serum folate concentration < 4.4 ng/mL. Ordinary least squares regression models were used to assess the association of serum folate with TSH concentration. Multivariable logistic regression models were performed to explore the correlation of folate deficiency and the risk for elevated TSH.

RESULTS

15.3% of T2DM patients had TD. Among those patients with TD, 80.5% had elevated TSH. Compared with the normal-TSH and low-TSH groups, the prevalence of folate deficiency was significantly higher in the elevated-TSH group (P < 0.001). Serum folate level was negatively associated with TSH (β=-0.062, 95%CI: -0.112, -0.012). Folate deficiency was associated with the higher risk for elevated TSH in patients with T2DM (OR = 8.562, 95%CI: 3.108, 23.588).

CONCLUSIONS

A low serum folate concentration was significantly associated with a higher risk for elevated TSH among T2DM patients.

Can Nutrition Contribute to a Reduction in Sarcopenia, Frailty, and Comorbidities in a Super-Aged Society?

Many countries are facing the advent of super-aging societies, where sarcopenia and frailty will become pertinent problems. The prevalence of comorbidities is a major problem in countries with aged populations as elderly people suffer from various diseases, such as diabetes, heart failure, chronic kidney disease and dementia. All of these diseases are associated with sarcopenia and frailty, and they frequently cause falls, fractures, and a decline in activities of daily living. Fractures in the elderly people are associated with bone fragility, which is influenced by diabetes and chronic kidney disease. Nutritional support for chronic disease patients and sarcopenic individuals with adequate energy and protein intake, vitamin D supplementation, blood glucose level management for individuals with diabetes, obesity prevention, nutritional education for healthy individuals, and the enlightenment of society could be crucial to solve the health-related problems in super-aging societies.

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.

Intended and Unintended Benefits of Folic Acid Fortification-A Narrative Review

Inadequate folate intake during pregnancy is the leading cause of the development of neural tube defects (NTDs) in newborns. For this reason, mandatory fortification of folic acid, a synthetic, easily bioavailable form, in processed cereals and cereal products has been implemented in the US since 1 January 1998 to reduce the risk of NTD in newborn children. This report aimed to review the literature related to the impact of mandated folic acid fortification on the intended and unintended benefits to health. Potential adverse effects were also discussed. We searched Pubmed, Google Scholar, Embase, SCOPUS, and Cochrane databases for reports. About 60 reports published between January 1998 and December 2022 were reviewed, summarized, and served as background for this review. The intended benefit was decreased prevalence of NTDs, while unintended benefits were reduction in anemia, blood serum homocysteine, and the risk of developing cardiovascular diseases. Potential issues with folic acid fortification are the presence of unmetabolized folic acid in circulation, increased risk of cancer, and the masking of vitamin B-12 deficiency. From a health perspective, it is important to monitor the impact of folic acid fortification periodically.

Exploratory analysis of the effect of a controlled lifestyle intervention on inflammatory markers - the Healthy Lifestyle Community Programme (cohort 2)

BACKGROUND

Chronic low-grade inflammation is associated with an increased risk of chronic disease and mortality. The objective of the study was to test the effect of a healthy lifestyle intervention on biomarkers of inflammation (among other risk markers).

METHODS

We conducted a non-randomized controlled trial with mostly middle-aged and elderly participants from the general population in rural northwest Germany (intervention: n = 114; control: n = 87). The intervention consisted of a 1-year lifestyle programme focusing on diet (largely plant-based; strongest emphasis), physical activity, stress management, and social support. High-sensitivity C-reactive protein (hs-CRP) was assessed at baseline, 10 weeks, 6 months, and 1 year. Homocysteine (Hcy) was assessed at baseline, 10 weeks, and 1 year. Adiponectin (Apn) was assessed at baseline and 10 weeks. An exploratory analysis of these inflammatory markers assessing the between-group differences with ANCOVA was conducted.

RESULTS

The 1-year trajectory of hs-CRP was significantly lower in the intervention group compared to control (between-group difference: -0.8 (95% CI -1.2, -0.3) mg/l; p = 0.001; adjusted for baseline). The 1-year trajectory of Hcy was non-significantly higher in the intervention compared to control (between-group difference: 0.2 (95% CI -0.3, 0.7) µmol/l; p = 0.439; adjusted for baseline). From baseline to 10 weeks, Apn decreased significantly more in the intervention group compared to control (between-group difference: -1.6 (95% CI -2.7, -0.5) µg/ml; p = 0.004; adjusted for baseline).

CONCLUSIONS

Our study shows that healthy lifestyle changes can lower hs-CRP and Apn levels and are unlikely to significantly affect Hcy levels within 1 year.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS; reference: DRKS00018775 , registered 12 Sept 2019; retrospectively registered; www.drks.de ).

The association of specific types of vegetables consumption with 10-year type II diabetes risk: Findings from the ATTICA cohort study

BACKGROUND

The present study aimed to investigate the association between vegetable consumption, in total as well as per type/category, and 10-year type-2 diabetes mellitus (T2DM) incidence.

METHODS

The ATTICA study was conducted during 2001-2012 in 3042 apparently healthy adults living in Athens area, Greece. A detailed biochemical, clinical, and lifestyle evaluation was performed; vegetable consumption (total, per type) was evaluated through a validated semi-quantitative food frequency questionnaire. After excluding those with no complete information of diabetes status or those lost at the 10-year follow-up, data from 1485 participants were used for the current analysis.

RESULTS

After adjusting for several participants' characteristics, including overall dietary habits, it was observed that participants consuming at least 4 servings/day of vegetables had a 0.42-times lower risk of developing T2DM (hazard ratio [HR] = 0.42; 95% confidence interval [CI] = 0.29-0.61); the benefits of consumption were greater in women (HR = 0.29; 95% CI = 0.16-0.53) compared to men (HR = 0.56; 95% CI = 0.34-0.92). Only 33% of the sample consumed vegetables 4 servings/day. The most significant associations were observed for allium vegetables in women and for red/orange/yellow vegetables, as well as for legumes in men.

CONCLUSIONS

The intake of at least 4 servings/day of vegetables was associated with a considerably reduced risk of T2DM, independently of other dietary habits; underlying the need for further elaboration of current dietary recommendations at the population level.

Dietary intake of folate and the frequency of its deficiency in children with type 1 diabetes mellitus and healthy children

Adequate folate intake is essential for a child’s growth. There is lack of information about the prevalence of this nutrient deficiency in the Ukrainian population, including children. The aim of the study was to evaluate the dietary intake of folate and determine the frequency of folate deficiency in children with Type 1 diabetes mellitus (T1D) and healthy children. Determination of folate in serum was performed by ELISA. Folate level <3 ng/ml was diagnosed as a folate deficiency. Among all observed children the folate deficiency was diagnosed in 23 (32.9%): in 6 (17.1%) patients with T1D and in 17 (48.6%) healthy children (P ≤ 0.01). The mean level of serum folate in patients with T1D was (5.09 ± 2.16) ng/ml and (3.72 ± 1.87) ng/ml in healthy children (P ≤ 0.01). The average daily intake of folate with food was (138.68 ± 70.37) µg, without difference between T1D (12.00 ± 3.51 yr.) and healthy groups (10.83 ± 3.24 yr.), and it was more than two times lower than age requirements (300 µg/day). However, it was self-reported that 15 (48.9%) children of T1D group received vitamin supplementation one time in six months, while in healthy children only 6 (17.1%) children received vitamins (P ≤ 0.01). In conclusion, the frequency of folate deficiency is high in the pediatric population. Nutrition does not provide the necessary intake of folate, which indicates the need for additional folate supplementation. Keywords: children., deficiency, diabetes mellitus, dietary intake, folate

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.

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.

Folic acid effect on homocysteine, sortilin levels and glycemic control in type 2 diabetes mellitus patients

Aim

The present study aimed to determine the folic acid supplement (FAS) effects on serum homocysteine and sortilin levels, glycemic indices, and lipid profile in type II diabetic patients.

Method

A double-blind randomized controlled clinical trial have been performed on 100 patients with T2DM randomly divided into two groups that received either placebo or folic acid 5 mg/d for 12 weeks.

Results

FAS caused a significant decrease in homocysteine and sortilin serum levels (28.2% and 33.7%, P < 0.0001, respectively). After 3 months of intervention, 8.7% decrease in fasting blood glucose (P = 0.0005), 8.2% in HbA1c (P = 0.0002), 13.7% in serum insulin (P < 0.0001) and 21.7% in insulin resistance (P < 0.0001) were found in the folic acid group, however no significant difference was observed in the placebo group. Serum hs-CRP level showed significant positive associations with sortilin (r = 0.237, P = 0.018), homocysteine (r = 0.308, P = 0.002) and fasting blood glucose (r = 0.342, P = 0.000). There were no significant changes in lipid profile in both groups after 12 weeks.

Conclusion

FAS might be beneficial for reducing homocysteine and sortilin levels, enhancing glycemic control, and improved insulin resistance in patients with T2DM.

ESPEN micronutrient guideline

BACKGROUND

Trace elements and vitamins, named together micronutrients (MNs), are essential for human metabolism. Recent research has shown the importance of MNs in common pathologies, with significant deficiencies impacting the outcome.

OBJECTIVE

This guideline aims to provide information for daily clinical nutrition practice regarding assessment of MN status, monitoring, and prescription. It proposes a consensus terminology, since many words are used imprecisely, resulting in confusion. This is particularly true for the words "deficiency", "repletion", "complement", and "supplement".

METHODS

The expert group attempted to apply the 2015 standard operating procedures (SOP) for ESPEN which focuses on disease. However, this approach could not be applied due to the multiple diseases requiring clinical nutrition resulting in one text for each MN, rather than for diseases. An extensive search of the literature was conducted in the databases Medline, PubMed, Cochrane, Google Scholar, and CINAHL. The search focused on physiological data, historical evidence (published before PubMed release in 1996), and observational and/or randomized trials. For each MN, the main functions, optimal analytical methods, impact of inflammation, potential toxicity, and provision during enteral or parenteral nutrition were addressed. The SOP wording was applied for strength of recommendations.

RESULTS

There was a limited number of interventional trials, preventing meta-analysis and leading to a low level of evidence. The recommendations underwent a consensus process, which resulted in a percentage of agreement (%): strong consensus required of >90% of votes. Altogether the guideline proposes sets of recommendations for 26 MNs, resulting in 170 single recommendations. Critical MNs were identified with deficiencies being present in numerous acute and chronic diseases. Monitoring and management strategies are proposed.

CONCLUSION

This guideline should enable addressing suboptimal and deficient status of a bundle of MNs in at-risk diseases. In particular, it offers practical advice on MN provision and monitoring during nutritional support.

Efficacy and Safety of Nutrient Supplements for Glycaemic Control and Insulin Resistance in Type 2 Diabetes: An Umbrella Review and Hierarchical Evidence Synthesis

Background: Nutrient supplements are widely used for type 2 diabetes (T2D), yet evidence-based guidance for clinicians is lacking. Methods: We searched the four electronic databases from November 2015−December 2021. The most recent, most comprehensive, high-ranked systematic reviews, meta-analyses, and/or umbrella reviews of randomised controlled trials in adults with T2D were included. Data were extracted on study characteristics, aggregate outcome measures per group (glycaemic control, measures of insulin sensitivity and secretion), adverse events, and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessments. Quality was assessed using A Measurement Tool to Assess Systematic Reviews Version 2.0 (AMSTAR 2). Results: Twelve meta-analyses and one umbrella review were included. There was very low certainty evidence that chromium, Vitamin C, and omega-3 polyunsaturated fatty acids (Ω-3 PUFAs) were superior to placebo for the primary outcome of glycated hemoglobin (HbA1c) (Mean Difference/MD −0.54, −0.54 and ES −0.27, respectively). Probiotics were superior to placebo for HbA1c (Weighted Mean Difference/WMD −0.43%). There was very low certainty evidence that Vitamin D was superior to placebo for lowering HbA1c in trials of <6 months (MD −0.17%). Magnesium, zinc, Vitamin C, probiotics, and polyphenols were superior to placebo for FBG. Vitamin D was superior to placebo for insulin resistance. Data on safety was limited. Conclusions: Future research should identify who may benefit from nutrient supplementation, safety, and optimal regimens and formulations.

Genetically-Guided Medical Nutrition Therapy in Type 2 Diabetes Mellitus and Pre-diabetes: A Series of n-of-1 Superiority Trials

Type 2 diabetes mellitus (T2DM) is a heterogeneous metabolic disorder of multifactorial etiology that includes genetic and dietary influences. By addressing the latter, medical nutrition therapy (MNT) contributes to the management of T2DM or pre-diabetes toward achieving glycaemic control and improved insulin sensitivity. However, the clinical outcomes of MNT vary and may further benefit from personalized nutritional plans that take into consideration genetic variations associated with individual responses to macronutrients. The aim of the present series of n-of-1 trials was to assess the effects of genetically-guided vs. conventional MNT on patients with pre-diabetes or T2DM. A quasi-experimental, cross-over design was adopted in three Caucasian adult men with either diagnosis. Complete diet, bioclinical and anthropometric assessment was performed and a conventional MNT, based on the clinical practice guidelines was applied for 8 weeks. After a week of “wash-out,” a precision MNT was prescribed for an additional 8-week period, based on the genetic characteristics of each patient. Outcomes of interest included changes in body weight (BW), fasting plasma glucose (FPG), and blood pressure (BP). Collectively, the trials indicated improvements in BW, FPG, BP, and glycosylated hemoglobin (HbA1c) following the genetically-guided precision MNT intervention. Moreover, both patients with pre-diabetes experienced remission of the condition. We conclude that improved BW loss and glycemic control can be achieved in patients with pre-diabetes/T2DM, by coupling MNT to their genetic makeup, guiding optimal diet, macronutrient composition, exercise and oral nutrient supplementation in a personalized manner.

Diet Quality Scores and Cardiometabolic Risk Factors in Mexican Children and Adolescents: A Longitudinal Analysis

There is limited evidence for the effects of diet on cardiometabolic profiles during the pubertal transition. We collected repeated measures of diet quality and cardiometabolic risk factors among Mexican youth. This analysis included 574 offspring of the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) birth cohort followed up to three time points. Dietary Approaches to Stop Hypertension (DASH), alternate Mediterranean Diet (aMedDiet), and Children’s Dietary Inflammatory Index (C-DIITM) scores were computed from food frequency questionnaires. Higher DASH and aMedDiet scores reflect a higher diet quality, and lower C-DII scores reflect an anti-inflammatory diet. Cardiometabolic risk factors were lipid profile, glucose homeostasis, blood pressure, and waist circumference. Linear mixed models were used between quartiles of each diet score and outcomes. Compared to the first quartile, the fourth DASH quartile was inversely associated with log serum insulin (μIU/mL) [β = −0.19, p = 0.0034] and log-Homeostatic Model Assessment of Insulin Resistance [β = −0.25, p = 0.0008]. Additionally, log serum triglycerides (mg/dL) was linearly associated with aMedDiet score [β = −0.03, p = 0.0022]. Boys in the highest aMedDiet quartile had higher serum high-density lipoprotein cholesterol (mg/dL) [β = 4.13, p = 0.0034] compared to the reference quartile. Higher diet quality was associated with a better cardiometabolic profile among Mexican youth.

The effects of dietary supplements and natural products targeting glucose levels: an overview

Identifying effective dietary supplements and medicinal herbs has attracted the attention of clinicians and researchers to complement the standard treatment in controlling diabetes mellitus. In the present overview, we aimed to collect studies with the highest level of evidence to shed light on detecting the most effective dietary supplements and medicinal herbs for controlling glycemic status. For the current overview, four electronic databases, including PubMed, Scopus, Web of Science, and Cochrane Library, were systematically searched from inception to 31 December 2020 and then updated until 1 October 2021 to obtain eligible meta-analyses on either dietary supplements or medicinal herbs and their effects on glycemic status. Fasting blood sugar (FBS) and Hemoglobin A1C (HbA1C) were considered as primary outcomes. Finally, ninety-one meta-analyses on dietary supplements (n = 55) and herbs (n = 36) were included. Evidence showed positive effects of chromium, zinc, propolis, aloe vera, milk thistle, fenugreek, cinnamon, ginger, and nettle on FBS and/or HbA1C. However, mostly the heterogeneity (I2) was high. Other supplements and herbs also showed no reduction in glucose levels or their effects were small. Although some dietary supplements and medicinal herbs showed a significant reduction in FBS and/or HbA1C, mostly their effects from the clinical point of view were not remarkable. In addition, due to high heterogeneity, publication bias, and a limited number of included studies in most cases further clinical trials are needed for making decision on anti-diabetic supplement efficacy.

The Effects of Folic Acid Supplementation on Pro-inflammatory Mediators: a Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

PURPOSE

Despite extensive research, findings regarding the effects of folic acid supplementation on inflammatory mediators have been controversial and inconclusive. This study therefore aimed to summarize the findings of all available clinical trials regarding the effects of folic acid supplementation on inflammatory biomarkers in adults.

METHODS

A systematic search was conducted of PubMed/MEDLINE, Scopus, Web of Science, EMBASE, and Google Scholar until April 2020. All randomized controlled trials that examined the influence of folic acid supplementation on C-reactive protein, interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) were included. Pooled effect sizes were calculated based on the random effects model, and dose-response analysis was modeled by using a fractional polynomial model.

FINDINGS

In total, 18 randomized controlled trials involving 2286 participants were analyzed. Folic acid supplementation significantly reduced serum levels of C-reactive protein (mean difference [MD], -0.21 mg/L; 95% CI, -0.41 to -0.01; n = 16), TNF-α (MD, -14.88 pg/mL; 95% CI, -23.68 to -6.09; n = 10), and IL-6 (MD, -0.93 pg/mL; 95% CI, -1.72 to -0.14; n = 11). Subgroup analyses suggested a significant reduction at doses ≤5 mg/d and studies longer than 12 weeks in duration. A significant nonlinear association was also found between folic acid dosage (P_nonlinearity <0.001) and duration of administration (P_nonlinearity <0.001) with serum TNF-α levels.

IMPLICATIONS

This meta-analysis indicates the beneficial effects of folic acid supplementation on pro-inflammatory cytokines. Further studies with a longer duration of administration, higher doses, and larger sample sizes should be performed exclusively on patients with chronic inflammatory disorders to elucidate the favorable role of folate intake on inflammatory biomarkers. International Prospective Register of Systematic Reviews identifier: CRD42021249947.

Maternal folic acid and multivitamin supplementation: International clinical evidence with considerations for the prevention of folate-sensitive birth defects

More evidence is available for maternal intake, absorption, distribution, tissue specific concentrations, and pregnancy outcomes with folic acid (fortification/supplementation) during preconception - first trimester. This Quality Improvement prevention review used expert guidelines/opinions, systematic reviews, randomized control trials/controlled clinical trials, and observational case control/case series studies, published in English, from 1990 to August 2021. Optimization for an oral maternal folic acid supplementation is difficult because it relies on folic acid dose, type of folate supplement, bio-availability of the folate from foods, timing of supplementation initiation, maternal metabolism/genetic factors, and many other factors. There is continued use of high dose pre-food fortification 'RCT evidenced-based' folic acid supplementation for NTD recurrence pregnancy prevention. Innovation requires preconception and pregnancy use of 'carbon one nutrient' supplements (folic acid, vitamin B12, B6, choline), using the appropriate evidence, need to be considered. The consideration and adoption of directed personalized approaches for maternal complex risk could use serum folate testing for supplementation dosing choice. Routine daily folic acid dosing for low-risk women should consider a multivitamin with 0.4 mg of folic acid starting 3 months prior to conception until completion of breastfeeding. Routine folic acid dosing or preconception measurement of maternal serum folate (after 4-6 weeks of folate supplementation) could be considered for maternal complex risk group with genetic/medical/surgical co-morbidities. These new approaches for folic acid oral supplementation are required to optimize benefit (decreasing folate sensitive congenital anomalies; childhood morbidity) and minimizing potential maternal and childhood risk.

Hyperhomocysteinemia: Metabolic Role and Animal Studies with a Focus on Cognitive Performance and Decline-A Review

Disturbances in the one-carbon metabolism are often indicated by altered levels of the endogenous amino acid homocysteine (HCys), which is additionally discussed to causally contribute to diverse pathologies. In the first part of the present review, we profoundly and critically discuss the metabolic role and pathomechanisms of HCys, as well as its potential impact on different human disorders. The use of adequate animal models can aid in unravelling the complex pathological processes underlying the role of hyperhomocysteinemia (HHCys). Therefore, in the second part, we systematically searched PubMed/Medline for animal studies regarding HHCys and focused on the potential impact on cognitive performance and decline. The majority of reviewed studies reported a significant effect of HHCys on the investigated behavioral outcomes. Despite of persistent controversial discussions about equivocal findings, especially in clinical studies, the present evaluation of preclinical evidence indicates a causal link between HHCys and cognition-related- especially dementia-like disorders, and points out the further urge for large-scale, well-designed clinical studies in order to elucidate the normalization of HCys levels as a potential preventative or therapeutic approach in human pathologies.

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.

Periconceptional folate and gestational diabetes mellitus: a systematic review and meta-analysis of cohort studies

OBJECTIVE

To examine the relationship between periconceptional folate exposure and risk of gestational diabetes mellitus (GDM).

METHODS

Several electronic databases, including PubMed, Embase, China National Knowledge Infrastructure (CNKI), China Biology Medicine (CBM), and Cochrane Library, were searched for all relevant cohort studies by January 2021. Studies on relationship between folate exposure (intake or status) and GDM risk were included. Quality of included studies was assessed using Newcastle-Ottawa Scale. Random effects meta-analysis was performed to estimate overall odds ratio (OR) and 95% confidence intervals (CIs) by Stata software (Stata Corp., College Station, TX).

RESULTS

Ten cohort studies with 40,244 pregnancies were eligible for quantitative meta-analysis. Significant association was observed between folate exposure and risk of GDM (OR = 1.24, p=.036, 95% CI: 1.01-1.52). Subgroup analysis revealed that periconceptional folate exposure of population in China (OR = 1.35, 95% CI: 1.09-1.67) but not in western countries, folate exposure during pregnancy (OR = 1.49, 95% CI: 1.22-1.81) but not before pregnancy, and internal folate exposure (OR = 1.36, 95% CI: 1.10-1.67), were significantly associated with increased GDM risk.

CONCLUSIONS

Overall, periconceptional folate exposure is positively associated with GDM risk, especially the exposure during pregnancy and exposure in Chinese populations.

Dietary folate intake and metabolic syndrome in participants of PREDIMED-Plus study: a cross-sectional study

PURPOSE

We examined the association between dietary folate intake and a score of MetS (metabolic syndrome) and its components among older adults at higher cardiometabolic risk participating in the PREDIMED-Plus trial.

METHODS

A cross-sectional analysis with 6633 with overweight/obesity participants with MetS was conducted. Folate intake (per 100 mcg/day and in quintiles) was estimated using a validated food frequency questionnaire. We calculated a MetS score using the standardized values as shown in the formula: [(body mass index + waist-to-height ratio)/2] + [(systolic blood pressure + diastolic blood pressure)/2] + plasma fasting glucose-HDL cholesterol + plasma triglycerides. The MetS score as continuous variable and its seven components were the outcome variables. Multiple robust linear regression using MM-type estimator was performed to evaluate the association adjusting for potential confounders.

RESULTS

We observed that an increase in energy-adjusted folate intake was associated with a reduction of MetS score (β for 100 mcg/day = - 0.12; 95% CI: - 0.19 to - 0.05), and plasma fasting glucose (β = - 0.03; 95% CI: - 0.05 to - 0.02) independently of the adherence to Mediterranean diet and other potential confounders. We also found a positive association with HDL-cholesterol (β = 0.07; 95% CI: 0.04-0.10). These associations were also observed when quintiles of energy-adjusted folate intake were used instead.

CONCLUSION

This study suggests that a higher folate intake may be associated with a lower MetS score in older adults, a lower plasma fasting glucose, and a greater HDL cholesterol in high-risk cardio-metabolic subjects.

Homocysteine and diabetes: Role in macrovascular and microvascular complications

Diabetes mellitus (DM) can lead to the development of macro- and microvascular complications. Homocysteine (Hcy) may play a role in the development of cardiovascular (CV) diseases (CVDs). The role of Hcy in the development of the vascular complications associated with DM is not clearly defined. Despite a strong initial assumption regarding the importance of Hcy in DM and its complications, over time "enthusiasm has waned" because several studies showed unconvincing and occasionally contradictory results. A universal conclusion is not easy to draw given the diversity of studies (e.g. number of patients, design, folic acid and vitamin B status, ethnic differences, genetic background). For some complications, most results encourages further investigation. Impaired renal function is a major independent determinant of high total Hcy (tHcy) levels. However, the role of hyperhomocysteinaemia (HHcy) in the development of diabetic kidney disease (DKD) has yet to be determined. Hcy-lowering therapies can significantly decrease Hcy levels but their effects on CVD risk reduction are conflicting. Further studies are needed to determine the influence of Hcy-lowering therapy on CVD risk reduction, especially in patients with DM.

Edible Microalgae and Their Bioactive Compounds in the Prevention and Treatment of Metabolic Alterations

Marine and freshwater algae and their products are in growing demand worldwide because of their nutritional and functional properties. Microalgae (unicellular algae) will constitute one of the major foods of the future for nutritional and environmental reasons. They are sources of high-quality protein and bioactive molecules with potential application in the modern epidemics of obesity and diabetes. They may also contribute decisively to sustainability through carbon dioxide fixation and minimization of agricultural land use. This paper reviews current knowledge of the effects of consuming edible microalgae on the metabolic alterations known as metabolic syndrome (MS). These microalgae include Chlorella, Spirulina (Arthrospira) and Tetraselmis as well as Isochrysis and Nannochloropsis as candidates for human consumption. Chlorella biomass has shown antioxidant, antidiabetic, immunomodulatory, antihypertensive, and antihyperlipidemic effects in humans and other mammals. The components of microalgae reviewed suggest that they may be effective against MS at two levels: in the early stages, to work against the development of insulin resistance (IR), and later, when pancreatic -cell function is already compromised. The active components at both stages are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and -3 PUFAs (eicosapentaenoic acid/docosahexaenoic acid; EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins, such as folate. As a source of high-quality protein, including an array of bioactive molecules with potential activity against the modern epidemics of obesity and diabetes, microalgae are proposed as excellent foods for the future. Moreover, their incorporation into the human diet would decisively contribute to a more sustainable world because of their roles in carbon dioxide fixation and reducing the use of land for agricultural purposes.

Effects of the dietary approach to stop hypertension (DASH) diet on blood pressure, blood glucose, and lipid profile in adolescents with hemophilia: A randomized clinical trial

Children with hemophilia are an enhanced risk of modifiable cardiovascular and metabolic abnormalities. There is currently no nutritional guideline to prevent or manage cardiometabolic risk factors in these patients. Therefore, the present study sought to investigate the effect of the Dietary Approaches to Stop Hypertension (DASH) diet on cardiovascular and metabolic risk factors among children with hemophilia. In this parallel randomized clinical trial, 40 children (all male) with hemophilia were randomly allocated to the DASH group (n = 20) or control group (n = 20) for 10 weeks. The intervention group received the DASH diet (50%-55% of energy from carbohydrate, 27%-30% of energy from fat and 16%-18% energy from protein), and the control group received nutritional recommendations based on healthy eating practices. Systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood sugar (FBS), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were measured at the beginning and end of the study. Serum vitamin C was measured as a biomarker of compliance with the DASH diet. Study was registered at IRCT.ir (IRCT20130903014551N6). A significant increase in serum vitamin C in the DASH diet group was observed compared to the control group (p = .001), indicating good compliance with the DASH diet. There was a significant reduction in SBP (-0.48 mmHg), DBP (-0.48 mmHg), FBS (-5.86 mg/dl), TC (-16.07 mg/dl), TG (-17.21 mg/dl), and LDL-C (-9.79 mg/dl), and a significant increase in HDL-C (3.39 mg/dl), in the DASH diet group compared with the control group. Adherence to the DASH diet in children with hemophilia yielded beneficial effects in blood pressure, lipid profiles, and FBS.

Response to a glucose tolerance test in early-lactation Holstein cows receiving a supplementation of biotin, folic acid, and vitamin B12

The aim of the study was to evaluate glucose and insulin metabolism of cows receiving a supplementation of biotin (B₈), folic acid (B₉), and vitamin B₁₂ (B₁₂) during the transition period. According to a 2 × 2 factorial arrangement, 32 cows were randomly assigned to 9 incomplete blocks according to their previous 305-d milk yield. Within each block, cows were randomly assigned to 1 of the following levels of biotin from -27 to 28 d relative to the parturition: (1) no biotin supplement (B₈-) or (2) 20 mg/d of dietary biotin (B₈+). Within each level of biotin, the cows received either (1) 2-mL weekly intramuscular injections of saline 0.9% NaCl (B₉B₁₂-) or (2) 2.6 g/d of dietary folic acid and 2-mL weekly intramuscular injections of 10 mg of vitamin B₁₂ (B₉B₁₂+). An intravenous glucose tolerance test was performed at 25 d in milk. Baseline plasma glucagon, glucose, and nonesterified fatty acid concentrations did not differ among treatments. For B₉B₁₂+ cows, baseline plasma insulin concentration and maximal glucose concentration after glucose administration were greater when also combined with biotin compared with no biotin combination, whereas there was no effect in B₉B₁₂- cows. There was no treatment effect on time to reach half-maximal glucose and insulin concentrations, glucose positive incremental area under the curve, and glucose and insulin clearance rates. Regarding insulin results, maximal plasma concentration and positive incremental area under the curve were respectively 51 and 74% greater for cows receiving the B₈ supplement than for cows who did not. Moreover, plasma nonesterified fatty acid concentration nadir tended to be reached later for B₈ cows. Insulin peak was reached earlier for cows in the group B₉B₁₂+ than cows in B₉B₁₂-, regardless of B₈ supplementation. Under the current conditions, our results suggested that cows receiving a B₈ supplement had a reduced insulin sensitivity in early lactation. Insulin response was faster for B₉B₁₂+ cows, but this was not translated into further improvements following the glucose administration challenge.

Mitochondrial GWAS and association of nuclear - mitochondrial epistasis with BMI in T1DM patients

BACKGROUND

BMI is a strong indicator of complications from type I diabetes, especially under intensive treatment.

METHODS

We have genotyped 435 type 1 diabetics using Illumina Infinium Omni Express Exome-8 v1.4 arrays and performed mitoGWAS on BMI. We identified additive interactions between mitochondrial and nuclear variants in genes associated with mitochondrial functioning MitoCarta2.0 and confirmed and refined the results on external cohorts: the Framingham Heart Study (FHS) and GTEx data. Linear mixed model analysis was performed using the GENESIS package in R/Bioconductor.

RESULTS

We find a borderline significant association between the mitochondrial variant rs28357980, localized to MT-ND2, and BMI (β = - 0.69, p = 0.056). This BMI association was confirmed on 1889 patients from FHS cohort (β = - 0.312, p = 0.047). Next, we searched for additive interactions between mitochondrial and nuclear variants. MT-ND2 variants interacted with variants in the genes SIRT3, ATP5B, CYCS, TFB2M and POLRMT. TFB2M is a mitochondrial transcription factor and together with TFAM creates a transcription promoter complex for the mitochondrial polymerase POLRMT. We have found an interaction between rs3021088 in MT-ND2 and rs6701836 in TFB2M leading to BMI decrease (inter_pval = 0.0241), while interaction of rs3021088 in MT-ND2 and rs41542013 in POLRMT led to BMI increase (inter_pval = 0.0004). The influence of these interactions on BMI was confirmed in external cohorts.

CONCLUSIONS

Here, we have shown that variants in the mitochondrial genome as well as additive interactions between mitochondrial and nuclear SNPs influence BMI in T1DM and general cohorts.

Vitamin B12 and Folate Concentrations in Recent-onset Type 2 Diabetes and the Effect of Metformin Treatment

CONTEXT

Vitamin B12 and folate deficiency are not only linked to hematological, neurological, and cardiovascular diseases, but are also associated with insulin resistance. Metformin can decrease vitamin B12 and folate concentrations.

OBJECTIVE

To examine (1) effects of short-term metformin treatment on serum holotranscobalamin (holoTC) and folate and (2) their association with insulin sensitivity in recent-onset type 2 diabetes.

DESIGN

This cross-sectional analysis comprised patients (known disease duration <12 months) on metformin monotherapy (MET, n = 123, 81 males, 53 ± 12 years) or nonpharmacological treatment (NPT, n = 126, 77 males, 54 ± 11 years) of the German Diabetes Study.

MAIN OUTCOME MEASURES

HoloTC (enzyme-linked immunosorbent assay), cobalamin, and folate (electrochemiluminescence); beta-cell function and whole-body insulin sensitivity, measured during fasting (HOMA-B, HOMA-IR) and intravenous glucose tolerance tests combined with hyperinsulinemic-euglycemic clamp tests.

RESULTS

HoloTC (105.4 [82.4, 128.3] vs 97 [79.7, 121.9] pmol/L) and folate concentrations (13.4 [9.3, 19.3] vs 12.7 [9.3, 22.0] nmol/L) were similar in both groups. Overall, holoTC was not associated with fasting or glucose-stimulated beta-cell function and insulin-stimulated glucose disposal. Cobalamin measurements yielded similar results in representative subgroups. In NPT but not MET, folate levels were inversely correlated with HOMA-IR (r = -0.239, P = .007). Folate levels did not relate to insulin sensitivity or insulin secretion in the whole cohort and in each group separately after adjustment for age, body mass index, and sex.

CONCLUSIONS

Metformin does not affect circulating holoTC and folate concentrations in recent-onset type 2 diabetes, rendering monitoring of vitamin B12 and folate dispensable, at least during the first 6 months after diagnosis or initiation of metformin.

Is There an Effect of Methyl Donor Nutrient Supplementation on Metabolic Syndrome in Humans?

Metabolic syndrome (MetS), also termed insulin resistance syndrome, has been defined by World Health Organization (WHO) as a multi-factorial disorder characterized by a wide array of cardiometabolic risk factors that increase the risk of coronary heart diseases, diabetes mellitus, and stroke [...].

Metformin and Micronutrient Status in Type 2 Diabetes: Does Polypharmacy Involving Acid-Suppressing Medications Affect Vitamin B12 Levels?

Metformin is the first-choice drug in uncomplicated type 2 diabetes (T2DM) and is effective in improving glycaemic control. It is the most widely prescribed oral antidiabetic medicine and has a good safety profile. However, there is an abundance of evidence that metformin use is associated with decreased Vitamin B12 status, though the clinical implications of this in terms of increased risk of diabetic peripheral neuropathy are debated. There is growing evidence that other B vitamins, vitamin D and magnesium may also be impacted by metformin use in addition to alterations to the composition of the microbiome, depending on the dose and duration of therapy. Patients using metformin for prolonged periods may, therefore, need initial screening with intermittent follow-up, particularly since vitamin B₁₂ deficiency has similar symptoms to diabetic neuropathy which itself affects 40-50% of patients with T2DM at some stage. Among patients with T2DM, 40% are reported to experience symptomatic gastroesophageal reflux disease (GORD), of whom 70% use oral antidiabetic medications. The most common medications used to treat GORD are proton pump inhibitors (PPIs) and antagonists of histamine selective H₂ receptors (H₂RAs), both of which independently affect vitamin B₁₂ and magnesium status. Research indicates that co-prescribing metformin with either PPIs or H₂RAs can have further deleterious effects on vitamin B₁₂ status. Vitamin B12 deficiency related to metformin and polypharmacy is likely to contribute to the symptoms of diabetic neuropathy which may frequently be under-recognised. This review explores current knowledge surrounding these issues and suggests treatment strategies such as supplementation.