The Effect of Prebiotics and Oral Anti-Diabetic Agents on Gut Microbiome in Patients with Type 2 Diabetes: A Systematic Review and Network Meta-Analysis of Randomised Controlled Trials

Gastrointestinal adverse effects of old and new antidiabetics: How do we deal with them in real life?

Diabetes is a public health problem with an estimated worldwide prevalence of 10% and a prevalence of 12% in Mexico. The costs resulting from this chronic-degenerative disease are significant. Treatment for diabetes involves different medication groups, some of which can cause significant gastrointestinal adverse effects, such as dyspepsia, nausea, vomiting, bloating, diarrhea, and constipation. The medications most frequently associated with said adverse effects are metformin, acarbose, and GLP-1 agonists. Gastrointestinal adverse effects negatively impact the quality of life and management of patients with diabetes. The factors of visceral neuropathy, acute dysglycemia, dysbiosis, and intestinal bacterial overgrowth contribute to the gastrointestinal symptoms in patients with diabetes, making it necessary to consider multiple etiologic factors in the presence of gastrointestinal symptoms, and not exclusively attribute them to the use of antidiabetics. Personalized treatment, considering gastrointestinal comorbidity and the type of drug utilized, is essential for mitigating the adverse effects and improving the quality of life in patients with diabetes. The aim of the present narrative review was to describe the gastrointestinal adverse effects of the antidiabetic drugs, their pathophysiologic mechanisms, and the corresponding therapeutic measures.

Nutrient quality in dietary therapy for diabetes and diabetic kidney disease

Dietary therapy is crucial for diabetes care with the aim of preventing the onset and progression of diabetes and its complications. The traditional approach to dietary therapy for diabetes has primarily focused on restricting the intake of the three major nutrients and rigorously controlling blood glucose levels. However, advancements in nutritional science have shown that within the three major nutrients - carbohydrates, proteins and lipids - there exist multiple types, each with distinct impacts on type 2 diabetes and its complications, sometimes even showing conflicting effects. In light of this, the present review shifts its focus from the quantity to the quality of the three major nutrients. It aims to provide an overview of how the differences in nutrient quality can influence onset and progression of type 2 diabetes and diabetic kidney disease, highlighting the diverse effects and, at times, contradictory impacts associated with each nutrient type.

Effects of a diverse prebiotic fibre supplement on HbA1c, insulin sensitivity and inflammatory biomarkers in pre-diabetes: a pilot placebo-controlled randomised clinical trial

Prebiotic fibre represents a promising and efficacious treatment to manage pre-diabetes, acting via complementary pathways involving the gut microbiome and viscosity-related properties. In this study, we evaluated the effect of using a diverse prebiotic fibre supplement on glycaemic, lipid and inflammatory biomarkers in patients with pre-diabetes. Sixty-six patients diagnosed with pre-diabetes (yet not receiving glucose-lowering medications) were randomised into treatment (thirty-three) and placebo (thirty-three) interventions. Participants in the treatment arm consumed 20 g/d of a diverse prebiotic fibre supplement, and participants in the placebo arm consumed 2 g/d of cellulose for 24 weeks. A total of fifty-one and forty-eight participants completed the week 16 and week 24 visits, respectively. The intervention was well tolerated, with a high average adherence rate across groups. Our results extend upon previous work, showing a significant change in glycated haemoglobin (HbA1c) in the treatment group but only in participants with lower baseline HbA1c levels (< 6 % HbA1c) (P = 0·05; treatment -0·17 ± 0·27 v. placebo 0·07 ± 0·29, mean ± sd). Within the whole cohort, we showed significant improvements in insulin sensitivity (P = 0·03; treatment 1·62 ± 5·79 v. placebo -0·77 ± 2·11) and C-reactive protein (P FWE = 0·03; treatment -2·02 ± 6·42 v. placebo 0·94 ± 2·28) in the treatment group compared with the placebo. Together, our results support the use of a diverse prebiotic fibre supplement for physiologically relevant biomarkers in pre-diabetes.

Understanding how pre- and probiotics affect the gut microbiome and metabolic health

The gut microbiome, a complex assembly of microorganisms, significantly impacts human health by influencing nutrient absorption, the immune system, and disease response. These microorganisms form a dynamic ecosystem that is critical to maintaining overall well-being. Prebiotics and probiotics are pivotal in regulating gut microbiota composition. Prebiotics nourish beneficial bacteria and promote their growth, whereas probiotics help maintain balance within the microbiome. This intricate balance extends to several aspects of health, including maintaining the integrity of the gut barrier, regulating immune responses, and producing metabolites crucial for metabolic health. Dysbiosis, or an imbalance in the gut microbiota, has been linked to metabolic disorders such as type 2 diabetes, obesity, and cardiovascular disease. Impaired gut barrier function, endotoxemia, and low-grade inflammation are associated with toll-like receptors influencing proinflammatory pathways. Short-chain fatty acids derived from microbial fermentation modulate anti-inflammatory and immune system pathways. Prebiotics positively influence gut microbiota, whereas probiotics, especially Lactobacillus and Bifidobacterium strains, may improve metabolic outcomes, such as glycemic control in diabetes. It is important to consider strain-specific effects and study variability when interpreting these findings, highlighting the need for further research to optimize their therapeutic potential. The aim of this report is therefore to review the role of the gut microbiota in metabolic health and disease and the effects of prebiotics and probiotics on the gut microbiome and their therapeutic role, integrating a broad understanding of physiological mechanisms with a clinical perspective.

Comparative analysis of pectin and prebiotics on human microbiota modulation in early life stages and adults

The gut microbiota is essential in human health, influencing various physiological processes ranging from digestion and metabolism to immune function and mental health. Dietary fiber pectins and prebiotics have emerged as key modulators of gut microbiota composition and function, offering potential therapeutic implications for promoting gut health and preventing intestinal inflammatory diseases. In this review, we explore the modulation of gut microbiota by dietary fiber pectins and prebiotics in infants and adults. We begin with an overview of the gut microbiota composition and function in different age groups, highlighting the factors in shaping microbial communities in both age groups, especially the effect of diet. We then delve into the impact of dietary fiber pectins and prebiotics on gut microbiota composition and function, examining their effects on digestive health, intestinal barrier integrity, immune function, metabolic health, and mental health across different life stages. We further compare how aging affects the gut function and immune system, and we discuss the main health outcomes associated with dietary fiber intake and prebiotics, including the impact on digestive health, improvement in immune function, improvement in cholesterol and glucose metabolism, weight management, mental health, and prevention of diseases. Finally, we highlight the challenges and future directions for research. By advancing the understanding of gut microbiota dynamics and translating scientific insights into clinical practice, it could harness the full potential of dietary fiber pectins and prebiotics to optimize gut health, improve overall well-being across the lifespan, and increase longevity.

Exploring the Significance of Gut Microbiota in Diabetes Pathogenesis and Management-A Narrative Review

Type 2 diabetes is a disease with significant health consequences for the individual. Currently, new mechanisms and therapeutic approaches that may affect this disease are being sought. One of them is the association of type 2 diabetes with microbiota. Through the enteric nervous system and the gut-microbiota axis, the microbiota affects the functioning of the body. It has been proven to have a real impact on influencing glucose and lipid metabolism and insulin sensitivity. With dysbiosis, there is increased bacterial translocation through the disrupted intestinal barrier and increased inflammation in the body. In diabetes, the microbiota's composition is altered with, for example, a more abundant class of Betaproteobacteria. The consequences of these disorders are linked to mechanisms involving short-chain fatty acids, branched-chain amino acids, and bacterial lipopolysaccharide, among others. Interventions focusing on the gut microbiota are gaining traction as a promising approach to diabetes management. Studies are currently being conducted on the effects of the supply of probiotics and prebiotics, as well as fecal microbiota transplantation, on the course of diabetes. Further research will allow us to fully develop our knowledge on the subject and possibly best treat and prevent type 2 diabetes.

Gut Microbiome and Polycystic Ovary Syndrome: Interplay of Associated Microbial-Metabolite Pathways and Therapeutic Strategies

Polycystic ovary syndrome (PCOS) is a multifaceted disease with an intricate etiology affecting reproductive-aged women. Despite attempts to unravel the pathophysiology, the molecular mechanism of PCOS remains unknown. There are no effective or suitable therapeutic strategies available to ameliorate PCOS; however, the symptoms can be managed. In recent years, a strong association has been found between the gut microbiome and PCOS, leading to the formulation of novel ideas on the genesis and pathological processes of PCOS. Further, gut microbiome dysbiosis involving microbial metabolites may trigger PCOS symptoms via many mechanistic pathways including those associated with carbohydrates, short-chain fatty acids, lipopolysaccharides, bile acids, and gut-brain axis. We present the mechanistic pathways of PCOS-related microbial metabolites and therapeutic opportunities available to treat PCOS, such as prebiotics, probiotics, and fecal microbiota therapy. In addition, the current review highlights the emerging treatment strategies available to alleviate the symptoms of PCOS.

Impact of metformin and Dysosmobacter welbionis on diet-induced obesity and diabetes: from clinical observation to preclinical intervention

AIMS/HYPOTHESIS

We aimed to investigate the association between the abundance of Dysosmobacter welbionis, a commensal gut bacterium, and metabolic health in human participants with obesity and diabetes, and the influence of metformin treatment and prebiotic intervention.

METHODS

Metabolic variables were assessed and faecal samples were collected from 106 participants in a randomised controlled intervention with a prebiotic stratified by metformin treatment (Food4Gut trial). The abundance of D. welbionis was measured by quantitative PCR and correlated with metabolic markers. The in vitro effect of metformin on D. welbionis growth was evaluated and an in vivo study was performed in mice to investigate the effects of metformin and D. welbionis J115T supplementation, either alone or in combination, on metabolic variables.

RESULTS

D. welbionis abundance was unaffected by prebiotic treatment but was significantly higher in metformin-treated participants. Responders to prebiotic treatment had higher baseline D. welbionis levels than non-responders. D. welbionis was negatively correlated with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and fasting blood glucose levels in humans with obesity and type 2 diabetes. In vitro, metformin had no direct effect on D. welbionis growth. In mice, D. welbionis J115T treatment reduced body weight gain and liver weight, and improved glucose tolerance to a better level than metformin, but did not have synergistic effects with metformin.

CONCLUSIONS/INTERPRETATION

D. welbionis abundance is influenced by metformin treatment and associated with prebiotic response, liver health and glucose metabolism in humans with obesity and diabetes. This study suggests that D. welbionis may play a role in metabolic health and warrants further investigation.

CLINICAL TRIAL

NCT03852069.

Prebiotics Progress Shifts in the Intestinal Microbiome That Benefits Patients with Type 2 Diabetes Mellitus

Hypoglycemic medications that could be co-administered with prebiotics and functional foods can potentially reduce the burden of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM). The efficacy of drugs such as metformin and sulfonylureas can be enhanced by the activity of the intestinal microbiome elaborated metabolites. Functional foods such as prebiotics (e.g., oligofructose) and dietary fibers can treat a dysbiotic gut microbiome by enhancing the diversity of microbial niches in the gut. These beneficial shifts in intestinal microbiome profiles include an increased abundance of bacteria such as Faecalibacterium prauznitzii, Akkermancia muciniphila, Roseburia species, and Bifidobacterium species. An important net effect is an increase in the levels of luminal SCFAs (e.g., butyrate) that provide energy carbon sources for the intestinal microbiome in cross-feeding activities, with concomitant improvement in intestinal dysbiosis with attenuation of inflammatory sequalae and improved intestinal gut barrier integrity, which alleviates the morbidity of T2DM. Oligosaccharides administered adjunctively with pharmacotherapy to ameliorate T2DM represent current plausible treatment modalities.

Carbohydrates for glycemic control: functional and microbiome aspects

PURPOSE OF REVIEW

Glycemia goals are used as indicators of control and progression in prediabetes and diabetes. Adopting healthy eating habits is essential. It is worth considering the quality of carbohydrates to help with dietary glycemic control. The present article aims to review recent meta-analyses published in the years 2021-2022 on the effects of dietary fiber and low glycemic index/load (LGI/LGL) foods on glycemic control and how gut microbiome modulation contributes to glycemic control.

RECENT FINDINGS

Data involving more than 320 studies were reviewed. The evidence allows us to infer that LGI/LGL foods, including dietary fiber intake, are associated with reduced fasting glycemia and insulinemia, postprandial glycemic response, HOMA-IR, and glycated hemoglobin, which are more evident in soluble dietary fiber. These results can be correlated with changes in the gut microbiome. However, the mechanistic roles of microbes or metabolites implicated in these observations continue to be explored. Some controversial data highlight the need for more homogeneity between studies.

SUMMARY

The properties of dietary fiber are reasonably well established for their glycemic homeostasis effects, including the fermentation aspects. Findings of gut microbiome correlations with glucose homeostasis can be incorporated into clinical nutrition practice. Target dietary fiber interventions on microbiome modulation can offer options to improve glucose control and contribute to personalized nutritional practices.

Understanding the Role of the Gut Microbiome in Diabetes and Therapeutics Targeting Leaky Gut: A Systematic Review

The gut microbiota has been studied and continues to be a developing area in the pathognomic development of metabolic diseases like diabetes. Treatment with diet changes, the addition of supplements like prebiotics/probiotics, and the impact of fecal microbial transplantation can be correlated to targeting changes in dysbiosis. Understanding the impacts of various anti-hyperglycemic agents such as metformin and the implications of post-bariatric surgery on the gut microbiota diversity has emerged. These areas of study are crucial to understanding the pathognomic aspects of diabetes disease progression at the microbial level of metabolic and inflammatory mechanisms, which may give more insight into focusing on the role of diet prebiotic/probiotic supplements as potential forms of prospective management in diabetes and the development of more agents that target gut microbiota, which harbors low-grade inflammation. Intestinal dysbiosis was consistently observed in the mechanism of gut microbial change in diabetic individuals, contributing to reduced insulin sensitivity and poor glycemic control. This systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 checklist. We performed a literature search using the PubMed, Google Scholar and Science Direct databases in accordance with the eligibility criteria and ultimately selected 14 articles for final analysis. The Scale for the Assessment of Narrative Review Articles (SANRA) and the PRISMA 2020 checklist were used to assess the quality of selected articles for cross-sectional studies, traditional literature reviews, and systematic reviews, respectively. We collected papers from 2012 to 2022 for this review. We gathered articles from databases, such as this study, which show there is a strong connection between microbiota and diabetes that appears to exist. The objective is to assess and identify any dietary and therapeutic agents that may alter the microbiota and potentially target and modulate insulin sensitivity. This review article will discuss the pathophysiological effects of gut microbiota in diabetes management and the impact of various gut biodiversity therapeutics that can aid in reversing insulin sensitivity.

Effects of combined treatment of probiotics and metformin in management of Type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Lifestyle changes and dietary intervention, including the use of probiotics, can modulate dysbiosis of gut microbiome and contribute to the management of type 2 diabetes mellitus (T2DM). This systematic review and meta-analysis aim to assess the efficacy of metformin plus probiotics versus metformin alone on outcomes in patients with T2DM.

METHODS

We searched MEDLINE and EMBASE from inception to February 2023 to identify all randomized controlled trials (RCTs), which compared the use of metformin plus probiotics versus metformin alone in adult patients with T2DM. Data were summarized as mean differences (MD) with 95% confidence interval (CI) and pooled under the random effects model. Findings Fourteen RCTs (17 comparisons, 1009 patients) were included in this systematic review. Pooled results show a significant decrease in fasting glucose (FG) (MD=-0.64, 95% CI=-1.06, -0.22) and HbA1c (MD=-0.29, 95% CI=-0.47, -0.10) levels in patients with T2DM treated with metformin plus probiotics versus metformin alone. The addition of probiotics to metformin resulted in lower odds of gastrointestinal adverse events (Odds ratio=0.18, 95% CI=0.09, 0.3.8; I²=0%).

CONCLUSIONS

The addition of probiotics to metformin therapy is associated with improvement in T2DM outcomes. However, high-quality and adequately reported RCTs are needed in the future to confirm our findings.

Rosiglitazone Does Not Affect the Risk of Inflammatory Bowel Disease: A Retrospective Cohort Study in Taiwanese Type 2 Diabetes Patients

Human studies on the effect of rosiglitazone on inflammatory bowel disease (IBD) are still lacking. We investigated whether rosiglitazone might affect IBD risk by using the reimbursement database of Taiwan's National Health Insurance to enroll a propensity-score-matched cohort of ever users and never users of rosiglitazone. The patients should have been newly diagnosed with diabetes mellitus between 1999 and 2006 and should have been alive on 1 January 2007. We then started to follow the patients from 1 January 2007 until 31 December 2011 for a new diagnosis of IBD. Propensity-score-weighted hazard ratios were estimated with regards to rosiglitazone exposure in terms of ever users versus never users and in terms of cumulative duration and cumulative dose of rosiglitazone therapy for dose-response analyses. The joint effects and interactions between rosiglitazone and risk factors of psoriasis/arthropathies, dorsopathies, and chronic obstructive pulmonary disease/tobacco abuse and the use of metformin were estimated by Cox regression after adjustment for all covariates. A total of 6226 ever users and 6226 never users were identified and the respective numbers of incident IBD were 95 and 111. When we compared the risk of IBD in ever users to that of the never users, the estimated hazard ratio (0.870, 95% confidence interval: 0.661-1.144) was not statistically significant. When cumulative duration and cumulative dose of rosiglitazone therapy were categorized by tertiles and hazard ratios were estimated by comparing the tertiles of rosiglitazone exposure to the never users, none of the hazard ratios reached statistical significance. In secondary analyses, rosiglitazone has a null association with Crohn's disease, but a potential benefit on ulcerative colitis (UC) could not be excluded. However, because of the low incidence of UC, we were not able to perform detailed dose-response analyses for UC. In the joint effect analyses, only the subgroup of psoriasis/arthropathies (-)/rosiglitazone (-) showed a significantly lower risk in comparison to the subgroup of psoriasis/arthropathies (+)/rosiglitazone (-). No interactions between rosiglitazone and the major risk factors or metformin use were observed. We concluded that rosiglitazone has a null effect on the risk of IBD, but the potential benefit on UC awaits further investigation.

The Association of Planetary Health Diet with the Risk of Type 2 Diabetes and Related Complications: A Systematic Review

BACKGROUND

Nutritional interventions such as the planetary health diet, which the EAT-Lancet commission proposed, may be an effective strategy for reducing type 2 diabetes risks and its associated complications. The planetary health diet demonstrates the significant role of diet in associating human health with environmental sustainability and the significance of transforming food systems in order to ensure that the UN's Sustainable Development Goals and the Paris Agreement are achieved. Therefore, the aim of this review is to examine the association of the planetary health diet (PHD) with the risk of type 2 diabetes and its related complications.

METHOD

The systematic review was conducted in line with established guidelines. The searches were carried out in health sciences research databases through EBSCOHost. The population, intervention, comparator and outcomes framework was used in order to define the research question and the search terms. The searches were carried out from the inception of the databases to 15 November 2022. Search terms including synonyms and medical subject headings were combined using Boolean operators (OR/AND).

RESULTS

Seven studies were included in the review and four themes were identified, including incidence of diabetes; cardiovascular risk factors and other disease risks; indicators of obesity and indicators of environmental sustainability. Two studies examined the association between the PHD and the incidence of type 2 diabetes and found that high adherence to the reference diet (EAT-Lancet reference diet) was correlated with a lower incidence of type 2 diabetes. High adherence to the PHD was also associated with some cardiovascular risk factors and environmental sustainability.

CONCLUSION

This systematic review has shown that high adherence to the PHD is associated with a reduced risk of type 2 diabetes and may be associated with a lower risk of subarachnoid stroke. In addition, an inverse relationship was found between adherence to the PHD and markers of obesity and environmental sustainability. Adherence to the reference diet was also associated with lower values of some markers of cardiovascular risk. More studies are needed to fully examine the relationship between the planetary health diet, type 2 diabetes and its related conditions.

The Effects of Nutrition on Chronic Conditions

The effects of nutrition on chronic conditions, such as diabetes, obesity, heart disease, and stroke, continue to generate interest among researchers [...].