The effects of probiotic bacteria on glycaemic control in overweight men and women: a randomised controlled trial

Gut microbiome: A revolution in type II diabetes mellitus

Type II diabetes mellitus (T2DM) has experienced a dramatic increase globally across countries of various income levels over the past three decades. The persistent prevalence of T2DM is attributed to a complex interplay of genetic and environmental factors. While numerous pharmaceutical therapies have been developed, there remains an urgent need for innovative treatment approaches that offer effectiveness without significant adverse effects. In this context, the exploration of the gut microbiome presents a promising avenue. Research has increasingly shown that the gut microbiome of individuals with T2DM exhibits distinct differences compared to healthy individuals, suggesting its potential role in the disease’s pathogenesis and progression. This emerging field offers diverse applications, particularly in modifying the gut environment through the administration of prebiotics, probiotics, and fecal microbiome transfer. These inter-ventions aim to restore a healthy microbiome balance, which could potentially alleviate or even reverse the metabolic dysfunctions associated with T2DM. Although current results from clinical trials have not yet shown dramatic effects on diabetes management, the groundwork has been laid for deeper investigation. Ongoing and future clinical trials are critical to advancing our understanding of the microbiome’s impact on diabetes. By further elucidating the mechanisms through which microbiome alterations influence insulin resistance and glucose metabolism, researchers can develop more targeted interventions. The potential to harness the gut microbiome in developing new therapeutic strategies offers a compelling prospect to transform the treatment landscape of T2DM, potentially reducing the disease’s burden significantly with approaches that are less reliant on traditional pharmaceuticals and more focused on holistic, systemic health improvements.

Effects of daily probiotic supplementation with Lactobacillus acidophilus on calcium status, bone metabolism biomarkers, and bone mineral density in postmenopausal women: a controlled and randomized clinical study

Background

Menopause poses significant health risks for women, particularly an increased vulnerability to fractures associated with osteoporosis. Dietary interventions have emerged as promising strategies, focusing on mitigating the risk of osteoporosis rather than solely addressing the established disease. This 12-week randomized controlled trial aimed to analyze the effects of consuming Lactobacillus acidophilus probiotics on calcium levels, biomarkers of bone metabolism, and bone mineral density (BMD) profiles in postmenopausal women.

Methods

Fifty-five participants were randomly assigned to receive either a placebo (n = 25) or the probiotic L. acidophilus UALa-01™ (n = 30) daily via oral intervention. Throughout the study, evaluations included body composition, blood biochemical parameters, serum calcium levels, and biomarkers of bone metabolism. Additionally, Dual-energy X-ray absorptiometry was used to measure BMD profiles.

Results

The findings delineated that the probiotic group experienced a decrease in serum calcium levels compared to their initial levels. However, hair calcium levels and biomarkers related to bone metabolism showed no notable changes within this group. Consumption of probiotic L. acidophilus also seemed to prevent fluctuations in bone turnover markers. Moreover, there were no significant alterations in BMD levels at the lumbar spine, left femur, and total body in the probiotic group. Additionally, probiotic intake led to favorable outcomes by significantly reducing both body fat and visceral fat during the intervention period. Conversely, an adverse effect of consuming probiotic L. acidophilus was observed with a significant increase in glucose concentration.

Conclusion

In conclusion, the consumption of L. acidophilus probiotics daily for 12 weeks among postmenopausal women does not affect the profile of BMD, but it may help in stabilizing bone turnover. It is important to note that most measured parameters were within the normal range for this population. However, it is worth noting that 3 months of probiotic supplementation could potentially disrupt calcium and glucose status in postmenopausal women.

Harnessing the Health and Techno-Functional Potential of Lactic Acid Bacteria: A Comprehensive Review

This review examines the techno-functional properties of lactic acid bacteria (LABs) in the food industry, focusing on their potential health benefits. We discuss current findings related to the techno-functionality of LAB, which includes acidification, proteolytic and lipolytic features, and a variety of other biochemical activities. These activities include the production of antimicrobial compounds and the synthesis of exopolysaccharides that improve food safety and consumer sensory experience. LABs are also known for their antioxidant abilities, which help reduce oxidative reactions in foods and improve their functional properties. In addition, LABs' role as probiotics is known for their promising effects on gut health, immune system modulation, cholesterol control, and general wellbeing. Despite these advantages, several challenges hinder the effective production and use of probiotic LABs, such as maintaining strain viability during storage and transport as well as ensuring their efficacy in the gastrointestinal tract. Our review identifies these critical barriers and suggests avenues for future research.

Insights into the Anti-Adipogenic and Anti-Inflammatory Potentialities of Probiotics against Obesity

Functional foods with probiotics are safe and effective dietary supplements to improve overweight and obesity. Thus, altering the intestinal microflora may be an effective approach for controlling or preventing obesity. This review aims to summarize the experimental method used to study probiotics and obesity, and recent advances in probiotics against obesity. In particular, we focused on studies (in vitro and in vivo) that used probiotics to treat obesity and its associated comorbidities. Several in vitro and in vivo (animal and human clinical) studies conducted with different bacterial species/strains have reported that probiotics promote anti-obesity effects by suppressing the differentiation of pre-adipocytes through immune cell activation, maintaining the Th1/Th2 cytokine balance, altering the intestinal microbiota composition, reducing the lipid profile, and regulating energy metabolism. Most studies on probiotics and obesity have shown that probiotics are responsible for a notable reduction in weight gain and body mass index. It also increases the levels of anti-inflammatory adipokines and decreases those of pro-inflammatory adipokines in the blood, which are responsible for the regulation of glucose and fatty acid breakdown. Furthermore, probiotics effectively increase insulin sensitivity and decrease systemic inflammation. Taken together, the intestinal microbiota profile found in overweight individuals can be modified by probiotic supplementation which can create a promising environment for weight loss along enhancing levels of adiponectin and decreasing leptin, tumor necrosis factor (TNF)-α, interleukin (IL)-6, monocyte chemotactic protein (MCP)-1, and transforming growth factor (TGF)-β on human health.

Microbial-Based Bioactive Compounds to Alleviate Inflammation in Obesity

The increased prevalence of obesity with several other metabolic disorders, including diabetes and non-alcoholic fatty liver disease, has reached global pandemic proportions. Lifestyle changes may result in a persistent positive energy balance, hastening the onset of these age-related disorders and consequently leading to a diminished lifespan. Although suggestions have been raised on the possible link between obesity and the gut microbiota, progress has been hampered due to the extensive diversity and complexities of the gut microbiota. Being recognized as a potential biomarker owing to its pivotal role in metabolic activities, the dysregulation of the gut microbiota can give rise to a persistent low-grade inflammatory state associated with chronic diseases during aging. This chronic inflammatory state, also known as inflammaging, induced by the chronic activation of the innate immune system via the macrophage, is controlled by the gut microbiota, which links nutrition, metabolism, and the innate immune response. Here, we present the functional roles of prebiotics, probiotics, synbiotics, and postbiotics as bioactive compounds by underscoring their putative contributions to (1) the reduction in gut hyperpermeability due to lipopolysaccharide (LPS) inactivation, (2) increased intestinal barrier function as a consequence of the upregulation of tight junction proteins, and (3) inhibition of proinflammatory pathways, overall leading to the alleviation of chronic inflammation in the management of obesity.

The effect of dairy products on liver fat and metabolic risk markers in males with abdominal obesity - a four-arm randomized controlled trial

BACKGROUND & AIMS

In recent years, epidemiological studies have reported links between the consumption of fermented dairy products, such as yogurt, and health; however, evidence from human intervention trials is scarce and inconsistent. We aimed to investigate the effect of consumption of four different types of dairy products (two fermented and two non-fermented) on liver fat (primary outcome) and metabolic risk markers in males with abdominal obesity.

METHODS

In this parallel randomized controlled trial with four arms, 100 males aged 30-70 years, with body mass index 28.0-45.0 kg/m2, and waist circumference ≥102 cm underwent a 16-weeks intervention where they were instructed to consume 400 g/day of either milk, yogurt, heat-treated yogurt, or acidified milk as part of their habitual diet. Liver fat was measured by magnetic resonance imaging.

RESULTS

In the complete case analyses (n = 80), no effects of the intervention or differences between groups were detected in anthropometry or body composition including liver fat. Moreover, no effects were detected in inflammatory markers. Main effects of time were detected in blood pressure (decrease; P < 0.001), insulin (decrease; P < 0.001), C-peptide (decrease; P = 0.040), homeostatic model assessment for insulin resistance (decrease; P < 0.001), total cholesterol (decrease; P = 0.016), low-density lipoprotein (decrease; P = 0.033), high-density lipoprotein (decrease; P = 0.006), and alanine transaminase (decrease; P = 0.019). Interactions between group and time failed to reach significance.

CONCLUSIONS

In conclusion, findings from our study do not confirm that fermented yogurt products are superior in reducing liver fat or improving metabolic risk markers compared to non-fermented milk products. In fact, all intervention products (both fermented yogurt products and non-fermented milk products) did not affect liver fat and caused largely similar modest favorable changes in some metabolic risk markers. The study was registered at www.

CLINICALTRIALS

gov (# NCT04755530).

Effect of probiotic supplementation on lipoprotein-associated phospholipase A2 in type 2 diabetic patients: a randomized double blind clinical controlled trial

BACKGROUND

It has been recently reported that lipoprotein-associated phospholipase A2 (Lp-PLA2) may predict the risk of cardiovascular disease. The effect of multi-strain probiotics on Lp-PLA2 in patients with type 2 diabetes is still not clear.

AIMS

This study aimed to determine the effect of multi-strain probiotic supplementation on lipoprotein-associated phospholipase A2, and glycemic status, lipid profile, and body composition in patients with type 2 diabetes.

METHODS

In this randomized double-blind placebo-controlled clinical trial, 68 participants with type 2 diabetes, in the age group of 50-65 years, were recruited and randomly allocated to take either probiotic (n = 34) or placebo (n = 34) for 12 weeks. The primary outcome was lipoprotein-associated phospholipase A2, and secondary outcomes were glycemic parameters, lipid profile, anthropometric characters, and body composition (fat mass and fat-free mass).

RESULTS

There was a significant reduction in serum lipoprotein-associated phospholipase A2, in the probiotic group, it dropped by 6.4 units at the end of the study (p < 0.001) compared to the placebo group. Probiotic supplementation also resulted in a significant improvement in the hemoglobin A1c and high-density lipoprotein cholesterol 1.5% (p < 0.001) and 6 mg/dl (p 0.005), respectively. There were no significant changes in other outcomes.

CONCLUSION

Probiotic supplementation was beneficial for reducing Lp-PLA2 and hemoglobin-A1c and improving high-density lipoprotein cholesterol, which may suggest an improvement in the prognosis in patients with type 2 diabetes.

Probiotics and Their Role in the Management of Type 2 Diabetes Mellitus (Short-Term Versus Long-Term Effect): A Systematic Review and Meta-Analysis

Diabetes is a major economic burden and an illness with a rising incidence worldwide. Type 2 diabetes mellitus (T2DM), the most prevalent kind of diabetes, is characterized by insulin resistance and insufficient insulin production. Recent research has implicated gut microbiota dysbiosis as a contributing factor to T2DM pathogenesis. The present study employed a methodology based on randomized controlled trials (RCTs) to assess the therapeutic efficacy of probiotics in the treatment of T2DM. A thorough search was done in PubMed and Medline for articles written in English and published between 2017 and 2023. Studies were chosen based on predetermined inclusion criteria, and the search technique adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) principles. This study also employed a robust assessment instrument, widely recognized in the medical and health sciences, to evaluate the potential presence of bias within the selected research studies. Out of 96 identified articles, 22 RCTs met the eligibility criteria. Both short-term (8 weeks or less) and long-term (12 weeks or more) probiotic administrations were made. The results of the meta-analysis demonstrated a significant improvement in the homeostatic model assessment of insulin resistance (HOMA-IR) following the probiotic intervention (P=0.02) and considerably decreased glycated hemoglobin HbA1c levels (P=0.004) and fasting blood glucose (FBG) levels (P<0.0001) in T2DM patients compared to placebo. This research offers proof that probiotics are clinically effective in the treatment of T2DM. Probiotic supplementation demonstrated favorable effects on glycemic control markers. However, the findings from RCTs were heterogeneous, and some studies showed inconsistent results. To clarify the processes underlying the probiotics' therapeutic benefits and to determine the best probiotic strains, doses, and therapy durations, more research is required. Nevertheless, probiotics offer a promising therapeutic approach for T2DM management and warrant consideration as a potential adjunct therapy in clinical practice.

Intermittent dietary carbohydrate restriction versus calorie restriction and cardiometabolic profiles: A randomized trial

OBJECTIVE

The aim of this study was to investigate the effectiveness of an intermittent low-carbohydrate diet (ILCD) versus calorie restriction (ICR) in young populations and potential mechanisms.

METHODS

Thirty-four participants aged 9 to 30 years with cardiometabolic risk were randomized to receive a self-administered 2-week ILCD (carbohydrate intake ≤ 50 g/d on seven nonconsecutive days) or ICR (500-600 kcal/d for two consecutive days per week). Differences in changes in obesity measures, glycemic and lipid profiles, gut microbiota composition, and three serum biomarkers were compared.

RESULTS

The ILCD and ICR similarly reduced body weight, waist circumference, fasting glucose, insulin, postprandial glucose variation, monocyte chemoattractant protein-1, free fatty acid, and fibroblast growth factor 21, whereas ILCD produced significantly different alterations in the following outcomes compared with ICR: greater increases in low-density lipoprotein cholesterol and total cholesterol (-0.36 mmol/L, 95% CI: -0.68 to -0.04; -0.40 mmol/L, 95% CI: -0.73 to -0.06) and greater decrease in triglyceride (0.20 mmol/L, 95% CI: 0.04 to 0.37). Actinobacteria and Bifidobacterium reduced after ILCD but not ICR; and the reductions strongly correlated with changes in fasting glucose (both r = 0.84) and low-density lipoprotein cholesterol (r = -0.81 and -0.72).

CONCLUSIONS

This study found no evidence of differences in changes from baseline in obesity measures, glucose regulation, and inflammation between ILCD and ICR, despite trends in reduction in those parameters. However, there seemed to be some differences in responses in lipids and gut microbiota.

Gut Microbiota and Aging: Traditional Chinese Medicine and Modern Medicine

The changing composition of gut microbiota, much like aging, accompanies people throughout their lives, and the inextricable relationship between both has recently attracted extensive attention as well. Modern medical research has revealed that a series of changes in gut microbiota are involved in the aging process of organisms, which may be because gut microbiota modulates aging-related changes related to innate immunity and cognitive function. At present, there is no definite and effective method to delay aging. However, Nobel laureate Tu Youyou's research on artemisinin has inspired researchers to study the importance of Traditional Chinese Medicine (TCM). TCM, as an ancient alternative medicine, has unique advantages in preventive health care and in treating diseases as it already has formed an independent understanding of the aging system. TCM practitioners believe that the mechanism of aging is mainly deficiency, and pathological states such as blood stasis, qi stagnation and phlegm coagulation can exacerbate the process of aging, which involves a series of organs, including the brain, kidney, heart, liver and spleen. Our current understanding of aging has led us to realise that TCM can indeed make some beneficial changes, such as the improvement of cognitive impairment. However, due to the multi-component and multi-target nature of TCM, the exploration of its mechanism of action has become extremely complex. While analysing the relationship between gut microbiota and aging, this review explores the similarities and differences in treatment methods and mechanisms between TCM and Modern Medicine, in order to explore a new approach that combines TCM and Modern Medicine to regulate gut microbiota, improve immunity and delay aging.

Effects of Probiotics on Intermediate Cardiovascular Outcomes in Patients with Overweight or Obesity: A Systematic Review and Meta-Analysis

Background: Clinical trials evaluating the effect of probiotics on cardiovascular intermediate outcomes have been scarce in recent years. We systematically evaluated the efficacy of probiotics on intermediate cardiovascular outcomes in patients with overweight or obesity. Methods: We searched for randomized controlled trials (RCTs) in four databases (until August 2021) that evaluated the effects of probiotics versus controls on intermediate cardiovascular outcomes. The outcomes were body mass index (BMI), weight, systolic blood pressure (SBP), diastolic blood pressure (DBP), glucose, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels. Inverse variance random effects meta-analyses were used. The effects were reported as mean difference (MD), with their 95% confidence intervals (95% CI). The quality of evidence (QoE) was assessed with GRADE (grading of recommendations, assessment, development and evaluations) methodology. Results: A total of 25 RCTs were included (n = 2170), with a range of follow-up from two to six months. Probiotics likely reduced BMI (MD −0.27 kg/m2, 95%CI: −0.35 to −0.19; 17 RCTs; I2 = 26%, QoE: moderate), as well as likely reduced weight (MD −0.61 kg, 95%CI: −0.89 to −0.34; 15 RCTs; I2 = 0%, QoE: moderate), and may have slightly reduce LDL (MD −4.08 mg/dL; 95%CI: −6.99 to −1.17; 9 RCTs; I2 = 87%, QoE: low) in comparison to the controls. However, probiotics had no effect on SBP (MD −0.40 mmHg; 95%CI: −5.04 to 4.25; 7 RCTs; I2 = 100%, QoE: very low), DBP (MD −1.73 mmHg; 95%CI: −5.29 to 1.82; 5 RCTs; I2 = 98%, QoE: very low), glucose (MD −0.07 mg/dL; 95%CI −0.89 to 0.75; I2 = 96%, QoE: very low), HDL (MD −1.83 mg/dL; 95%CI: −4.14 to 2.47; 14 RCTs; I2 = 98%, QoE: very low), or triglycerides (MD −3.29 mg/dL, 95%CI −17.03 to 10.45; 14 RCTs, I2 = 95%, QoE: very low) compared to control arms, and the evidence was very uncertain. Conclusions: In obese or overweight patients, BMI, weight, and LDL were lower in patients who received probiotics compared to those who received controls. Other lipids, glucose, and blood pressure were not affected by the probiotics.

Journey of the Probiotic Bacteria: Survival of the Fittest

This review aims to bring a more general view of the technological and biological challenges regarding production and use of probiotic bacteria in promoting human health. After a brief description of the current concepts, the challenges for the production at an industrial level are presented from the physiology of the central metabolism to the ability to face the main forms of stress in the industrial process. Once produced, these cells are processed to be commercialized in suspension or dried forms or added to food matrices. At this stage, the maintenance of cell viability and vitality is of paramount for the quality of the product. Powder products requires the development of strategies that ensure the integrity of components and cellular functions that allow complete recovery of cells at the time of consumption. Finally, once consumed, probiotic cells must face a very powerful set of physicochemical mechanisms within the body, which include enzymes, antibacterial molecules and sudden changes in pH. Understanding the action of these agents and the induction of cellular tolerance mechanisms is fundamental for the selection of increasingly efficient strains in order to survive from production to colonization of the intestinal tract and to promote the desired health benefits.

Saudi Traditional Fermented Goat Milk Protects against Experimental Non-Alcoholic Fatty Liver Disease by Hypoglycaemic and Antioxidant Potentials

This study examined the effect of fermented goat milk (oggtt) against non-alcoholic fatty liver disease (NAFLD) in rats induced by chronic high-fat diet (HFD) treatments. Both control-fed and HFD-fed adult male rats received the same vehicle or treatment with two doses of freshly collected oggtt (2 mL or 5 mL) for 12 weeks (n = 8/group). The treatment of the control and HFD-fed rats with oggtt in both doses significantly reduced weight gain, but fasting serum glucose and insulin levels as well as HOMA-IR levels were lowered only in the HFD-fed rats. Treatment improved HFD-induced glucose and insulin homeostasis impairment as measured by the oral glucose tolerance test. Both doses of oggtt reduced serum levels of liver function markers and C-reactive protein (CRP) as well as hepatic levels of malondialdehyde (MDA), tumour necrosis factor-α (TNF-α), and in-terlukin-6 (IL-6) in HFD-fed rats. In addition, the oggtt doses reduced serum and hepatic levels of triglycerides (TGs) and cholesterol (CHOL) as well as serum levels of low-density lipoproteins (LDL) in these rats. These biochemical endpoints were reflected by the improvement in liver histology and reduction in the number of fatty vacuolated and pyknotic cells. In both the control and HFD-fed rats, oggtt at both doses stimulated levels of superoxide dismutase (SOD) and glutathione (GSH). All these effects were more profound with the highest dose of oggtt. In conclusion, the finding of this study strongly supports the use of oggtt as a functional food to treat NAFLD, as it has shown hypoglycaemic and antioxidant properties.

Probiotic Mechanisms Affecting Glucose Homeostasis: A Scoping Review

The maintenance of a healthy status depends on the coexistence between the host organism and the microbiota. Early studies have already focused on the nutritional properties of probiotics, which may also contribute to the structural changes in the gut microbiota, thereby affecting host metabolism and homeostasis. Maintaining homeostasis in the body is therefore crucial and is reflected at all levels, including that of glucose, a simple sugar molecule that is an essential fuel for normal cellular function. Despite numerous clinical studies that have shown the effect of various probiotics on glucose and its homeostasis, knowledge about the exact function of their mechanism is still scarce. The aim of our review was to select in vivo and in vitro studies in English published in the last eleven years dealing with the effects of probiotics on glucose metabolism and its homeostasis. In this context, diverse probiotic effects at different organ levels were highlighted, summarizing their potential mechanisms to influence glucose metabolism and its homeostasis. Variations in results due to different methodological approaches were discussed, as well as limitations, especially in in vivo studies. Further studies on the interactions between probiotics, host microorganisms and their immunity are needed.

Gut Microbiota and Complications of Type-2 Diabetes

The gut microbiota has been linked to the emergence of obesity, metabolic syndrome and the onset of type 2 diabetes through decreased glucose tolerance and insulin resistance. Uncontrolled diabetes can lead to serious health consequences such as impaired kidney function, blindness, stroke, myocardial infarction and lower limb amputation. Despite a variety of treatments currently available, cases of diabetes and resulting complications are on the rise. One promising new approach to diabetes focuses on modulating the gut microbiota with probiotics, prebiotics, synbiotics and fecal microbial transplantation. Differences in gut microbiota composition have been observed in preclinical animal models as well as patients with type 2 diabetes and complications such as diabetic nephropathy, diabetic retinopathy, diabetic neuropathy, cerebrovascular disease, coronary heart disease and peripheral artery disease compared to healthy controls. Severity of gut microbiota dysbiosis was associated with disease severity and restoration with probiotic administration in animal models and human patients has been associated with improvement of symptoms and disease progression. Characterizing the gut microbiota dysbiosis in different diseases and determining a causal relationship between the gut microbiota and disease can be beneficial in formulating therapeutic interventions for type 2 diabetes and associated complications. In this review, we present the most important findings regarding the role of the gut microbiota in type 2 diabetes and chronic complications as well as their underlying mechanisms.

Effects of probiotics on body adiposity and cardiovascular risk markers in individuals with overweight and obesity: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Evidence suggests that gut microbiota is a potential factor in the pathophysiology of both obesity and related metabolic disorders. While individual randomized controlled trials (RCTs) have evaluated the effects of probiotics on adiposity and cardiovascular disease (CVD) risk factors in subjects with overweight and obesity, the results are inconsistent. Thus, this systematic review and meta-analysis aimed to evaluate the effects of probiotic supplementation on body weight, body adiposity and CVD risk markers in overweight and obese subjects.

METHODS

A systematic search for RCTs published up to December 2020 was conducted in MEDLINE (via PubMed), EMBASE, Scopus and LILACS. Meta-analysis using a random-effects model was chosen to analyze the impact of combined trials.

RESULTS

Twenty-six RCTs (n = 1720) were included. Data pooling showed a significant effect of probiotics in reducing body weight (MD:-0.70 kg; 95%CI:-1.04,-0.35 kg; P < 0.0001), body mass index (BMI) (MD:-0.24 kg/m²; 95%CI:-0.35,-0.12 kg/m²; P = 0.0001), waist circumference (WC) (MD:-1.13 cm; 95%CI:-1.54,-0.73 cm; P < 0.0001), fat mass (MD:-0.71 kg; 95%CI:-1.10,-0.32 kg; P = 0.0004), tumor necrosis factor-α (MD:-0.16 pg/ml; 95%CI:-0.24,-0.08 pg/ml; P = 0.0001), insulin (MD:-0.85mcU/ml; 95%CI:-1.50,-0.21mcU/ml; P = 0.010), total cholesterol (MD:-0.16 mmol/l; 95%CI:-0.26,-0.05 mmol/l; P = 0.003) and LDL (MD:-0.09 mmol/l; 95%CI:-0.16,-0.03 mmol/l; P = 0.006) compared with control groups. There was a significant decrease in body weight, BMI and WC in studies using both single and multi-bacterial species. Decreases in body adiposity parameters were only observed in studies using a probiotic dose of ≥ 10¹⁰ CFU and for ≥8 weeks duration.

CONCLUSIONS

The present meta-analysis suggests that probiotics consumption may be helpful for improving body weight, body adiposity and some CVD risk markers in individuals with overweight and obesity. The review was registered on PROSPERO (International prospective register of systematic reviews): CRD42020183136.

Probiotics Contribute to Glycemic Control in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

This systematic review aimed to evaluate the effectiveness and safety of probiotics for glycemic control in adults with impaired glucose control, including prediabetes and type 2 diabetes mellitus (T2DM). We searched PubMed, Embase, and Cochrane databases, and trial registries up to February 2019. We included randomized controlled trials (RCTs) of participants with prediabetes or T2DM. Eligible trials compared probiotics versus either placebo, no intervention, or comparison probiotics, or compared synbiotics versus prebiotics. Primary outcomes were mean change in fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) from baseline to short term (<12 wk) and long term (≥12 wk). We performed meta-analyses using the random-effects model. We included 28 RCTs (1947 participants). Overall, probiotics reduced FBG more than the placebo/no intervention group with a mean difference (MD) of -12.99 mg/dL (95% CI: -23.55, -2.42; P value: 0.016) over the short term; and -2.99 mg/dL (95% CI: -5.84, -0.13; P value: 0.040) over the long term. There was also some evidence for reduced HbA1c in the probiotics group at both short term (MD: -0.17; 95% CI: -0.37, 0.02; P value: 0.084) and long term (MD: -0.14; 95% CI: -0.34, 0.06; P value: 0.172), however, these did not reach statistical significance possibly because only a few trials reported HbA1c as an outcome. Subgroup analyses showed a greater reduction in HbA1c in participants not receiving insulin therapy than those receiving insulin therapy. Furthermore, the effect of probiotics on the reduction of FBG was more pronounced in participants with FBG >130 mg/dL and those not receiving insulin therapy than their counterparts. Probiotics were also effective in lowering serum cholesterol over the short and long term. In conclusion, we found that probiotics may have a glucose-lowering effect in T2DM participants. The effect appeared to be stronger in participants with poorly controlled diabetes and those not on insulin therapy. Systematic review registration: CRD42019121682.

Metabolites Linking the Gut Microbiome with Risk for Type 2 Diabetes

PURPOSE OF REVIEW

An increasing body of evidence suggests that the gut microbiome influences the pathogenesis of insulin resistance and type 2 diabetes (T2D). In this review, we will discuss the latest findings regarding the mechanisms linking the gut microbiome and microbial metabolites with T2D and therapeutic approaches based on the gut microbiota for the prevention and treatment of T2D.

RECENT FINDINGS

Alterations in the gut microbial composition are associated with the risk of T2D. The gut microbiota can metabolize dietary- and host-derived factors to produce numerous microbial metabolites, which are involved in metabolic processes modulating nutrition and energy harvest, gut barrier function, systemic inflammation, and glucose metabolism. Microbial metabolites are important mediators of microbial-host crosstalk impacting host glucose metabolism. Furthermore, microbiome-based interventions may have beneficial effects on glycemic control. Future research is required to develop personalized T2D therapy based on microbial composition and/or metabolites.

Probiotics as a therapeutic strategy in obesity and overweight: a systematic review

Obesity and overweight are two of the most health challenges with an increasing prevalence in recent years, in which several complications have been identified to have a high impact in patients' health conditions. In this vein, an increasing interest in the gut microbiota has emerged as a target for therapeutic strategies in obesity and overweight due to its direct relation with the aforementioned health conditions and complications. Thus, the aim of this study was to evaluate the efficacy of probiotics as a therapeutic strategy in the management of obesity and overweight. A systematic review of randomised controlled trials was carried out in 6 databases until May 2019 to assess the use of probiotics in obesity and overweight patients. The Jadad Scale was used to assess the quality of the clinical trials. Twenty-three clinical trials published between 2000 and 2019 met the inclusion criteria. The role of probiotics in reducing body mass index and weight as well as changing the visceral abdominal fat area, waist and hip circumference were shown in 14 of 23 trials (60.87%); 14 trials (60.87%) showed changes on patients' fatty acids and biomarkers; and 4 trials (17.39%) studied the role of the gut microbiota in obese and overweight patients. Some probiotics strains are shown to be effective in reducing body mass index and hip circumference. This review provides evidence of successful results in weight loss using probiotic groups.

Effects of Probiotic Supplementation on Dyslipidemia in Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

The effectiveness of probiotic consumption in controlling dyslipidemia in type 2 diabetes mellitus (T2DM) has been unclear. We reviewed relevant randomized controlled trials (RCTs) to clarify the effect of probiotic intake on dyslipidemia in T2DM patients. The Web of Science, Scopus, PubMed and Cochrane Library databases were used for searching relevant RCTs published up to October 2020. The total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) concentrations were selected as the primary indicators for dyslipidemia. The results of 13 eligible RCTs showed that probiotic intake could significantly reduce TC (SMD: −0.23, 95% CI: (−0.37, −0.10)) and TG (SMD: −0.27, 95% CI: (−0.44, −0.11)) levels, but did not regulate LDL-C or HDL-C concentrations. Subgroup analysis showed that multispecies probiotics (≥two species), but not single-species probiotics, significantly decreased TC and TG concentrations. Furthermore, powder, but not liquid, probiotics could reduce TC and TG concentrations. This meta-analysis demonstrated that probiotic supplementation is helpful in reducing TC and TG concentrations in T2DM patients. However, more well-controlled trials are needed to clarify the benefits of probiotics on dyslipidemia in T2DM patients.

Probiotics have minimal effects on appetite-related hormones in overweight or obese individuals: A systematic review of randomized controlled trials

BACKGROUND & AIMS

Overweight and obese individuals show changes in mechanisms related to appetite due to several factors, including excess fat and gut microbiota imbalance. Probiotics have been presented as a strategy for modulating gut microbiota and regulating these mechanisms. The aim of this systematic review was to assess the effects of probiotics on appetite-related hormones in overweight or obese individuals.

METHODS

A systematic review of randomized controlled trials was performed in nine electronic databases (Pubmed, Scopus, Web of Science, Cochrane Controlled Register of Trials, ProQuest Dissertations and Theses, PsycINFO, WHO International Clinical Trials Registry Platform, ClinicalTrials.gov and Open Grey) and in a manual search of studies until March 20, 2020. The risk of bias of each study was appraised using the RoB 2.0 tool. All research stages were carefully based on PRISMA recommendations.

RESULTS

Twenty-four studies (1587 participants) were included in this systematic review. The outcomes related to appetite assessed in the included studies were: leptin, insulin, adiponectin, resistin, nesfatin-1, adropin, omentin-1, GLP-1, GLP-2 and glucagon. Compared to the control group after supplementation, four studies involving 272 participants reported statistically significant reduction in fasting insulin. On the other hand, one study involving 56 participants reported statistically significant increase in adropin and omentin-1.

CONCLUSIONS

Probiotics have minimal effects on appetite-related hormones in overweight or obese individuals. However, knowledge in this area is progressing and further studies with a low risk of bias may help to clarify the role of probiotics in appetite control.

Antidiabetic and Hypolipidaemic Action of Finger Millet (Eleusine coracana)-Enriched Probiotic Fermented Milk: An in vivo Rat Study

Research background

Diabetes is a chronic multi-system disease having long term consequences to the health of people suffering from it. This study investigates the role of finger millet (Eleusine coracana)-enriched probiotic fermented milk in alleviating the diabetic complications in streptozotocin-induced diabetic rats.

Experimental approach

The probiotic strain used in the study was Lactobacillus helveticus MTCC 5463. Study comprised six groups each containing 6 Sprague Dawley rats: two controls (nondiabetic and diabetic), and four diabetic groups fed finger millet-enriched probiotic fermented milk, probiotic fermented milk, finger millet flour or metformin (standard drug). Samples were administered orally for four weeks, and parameters associated with diabetic disorders were studied.

Results and conclusions

Oral administration of finger millet-enriched milk significantly (p<0.001) decreased (64.26%) the fasting blood glucose level of diabetic rats compared to metformin (56.43%) and diabetic groups receiving the probiotic fermented milk (18.88%) and finger millet flour (47.14%) after four weeks of treatment. The finger millet-enriched milk significantly ameliorated the diabetic symptoms polyphagia and polydipsia and improved body mass. In diabetic control group, body mass was reduced up to 15.60% at the end of experiment, while in the group receiving the probiotic fermented milk, body mass significantly (p<0.0001) increased by about 5-30%. Significant (p<0.0001) reduction in total cholesterol, triglyceride levels in the groups treated with finger millet flour, finger millet-enriched probiotic fermented milk and probiotic fermented milk was observed compared to diabetic control rats. The probiotic fermented milk enriched with finger millet caused significant (p<0.05) decrease in low-density lipoprotein and very-low-density lipoprotein levels (p<0.0001) and insignificant increase in high-density lipoprotein level. A reversal of altered activities of hepatic marker enzymes aspartate transaminase and alanine transaminase was observed in the group receiving the probiotic milk enriched with finger millet. Histological observations of pancreatic tissues and liver showed that the enriched milk prevents more severe changes in the acinar cells and ameliorated the inflammation and alteration in the liver structure to some extent. Therefore, the finger millet-enriched probiotic fermented milk can be a potential functional food in the management of diabetes.

Novelty and scientific contribution

This is the only paper reporting about the antidiabetic potential of finger millet-enriched milk fermented using probiotic Lactobacillus helveticus MTCC 5463 and Streptococcus thermophilus MTCC 5460. It also shows the synergistic antidiabetic effect of milk and finger millet used in combination, thus offering a novel functional food.

Probiotics for the Treatment of Overweight and Obesity in Humans-A Review of Clinical Trials

The World Health Organization (WHO) reports that 400 million people are obese, and over 1.6 billion adults are overweight worldwide. Annually, over 2.8 million people die from obesity-related diseases. The incidence of overweight and obesity is steadily increasing, and this phenomenon is referred to as a 21st-century pandemic. The main reason for this phenomenon is an easy access to high-energy, processed foods, and a low-activity lifestyle. These changes lead to an energy imbalance and, as a consequence, to the development of body fat. Weight gain contributes to the development of heart diseases, skeletal system disorders, metabolic disorders such as diabetes, and certain types of cancer. In recent years, there have been many works linking obesity with intestinal microbiota. Experiments on germ-free animals (GFs) have provided much evidence for the contribution of bacteria to obesity. The composition of the gut microbiota (GM) changes in obese people. These changes affect the degree of energy obtained from food, the composition and secretory functions of adipose tissue, carbohydrate, and lipid metabolism in the liver, and the activity of centers in the brain. The study aimed to present the current state of knowledge about the role of intestinal microbiota in the development of obesity and the impact of supplementation with probiotic bacteria on the health of overweight and obese patients.

The Effect of Probiotics and Synbiotics on Risk Factors Associated with Cardiometabolic Diseases in Healthy People-A Systematic Review and Meta-Analysis with Meta-Regression of Randomized Controlled Trials

We aimed to systematically review the effectiveness of probiotic/synbiotic formulations to counteract cardiometabolic risk (CMR) in healthy people not receiving adjunctive medication. The systematic search (PubMed/MEDLINE/Embase) until 1 August 2019 was performed for randomized controlled trials in >20 adult patients. Random-effect meta-analysis subgroup and meta-regression analysis of co-primary (haemoglobin A1c (HbA1C), glucose, insulin, body weight, waist circumference (WC), body mass index (BMI), cholesterol, low-density lipoproteins (LDL), high-density lipoproteins (HDL), triglycerides, and blood pressure) and secondary outcomes (uric acid, plasminogen activator inhibitor-1-PAI-1, fibrinogen, and any variable related to inflammation/endothelial dysfunction). We included 61 trials (5422 persons). The mean time of probiotic administration was 67.01 ± 38.72 days. Most of probiotic strains were of Lactobacillus and Bifidobacterium genera. The other strains were Streptococci, Enterococci, and Pediococci. The daily probiotic dose varied between 10⁶ and 10¹⁰ colony-forming units (CFU)/gram. Probiotics/synbiotics counteracted CMR factors (endpoint data on BMI: standardized mean difference (SMD) = -0.156, p = 0.006 and difference in means (DM) = -0.45, p = 0.00 and on WC: SMD = -0.147, p = 0.05 and DM = -1.21, p = 0.02; change scores on WC: SMD = -0.166, p = 0.04 and DM = -1.35, p = 0.03) in healthy persons. Overweight/obese healthy people might additionally benefit from reducing total cholesterol concentration (change scores on WC in overweight/obese: SMD: -0.178, p = 0.049). Poor quality of probiotic-related trials make systematic reviews and meta-analyses difficult to conduct and draw definite conclusions. "Gold standard" methodology in probiotic studies awaits further development.

The effect of synbiotic on glycemic profile and sex hormones in overweight and obese breast cancer survivors following a weight-loss diet: A randomized, triple-blind, controlled trial

BACKGROUND

The investigation was designed to assess the effects of synbiotic supplementation on glycemic profile, insulin-like growth factor-1 (IGF-1) and sex hormones in overweight and obese postmenopausal breast cancer survivors (BCSs) who had hormone-receptor-positive breast cancer.

METHODS

This randomized, triple-blind, placebo-controlled trial was conducted on 76 overweight and obese BCSs aged 57.43 (5.82) years. All participants were given a specified low calorie diet and were randomly assigned into two groups to intake 10⁹ CFU/day of synbiotic supplement (n = 38) or placebo (n = 38) for 8 weeks. Body composition, physical activity, glycemic profile, IGF-1, estradiol, testosterone and dehydroepiandrosterone sulfate (DHEA-S) were measured at baseline and after 8 weeks.

RESULTS

A significant reduction in serum insulin (median change (Q1, Q3) from baseline of -1.05 (-2.36, 0.32) μIU/mL; P = 0.006) and insulin resistance (HOMA-IR) (mean change (SD) from baseline of -4.0 (0.9); P = 0.007) were seen over the 8 weeks in the synbiotic group. However, no significant changes were observed in serum insulin, fasting plasma glucose, HbA1c, HOMA-IR, IGF-1, estradiol, testosterone, DHEA-S and sex hormone binding globulin between-groups at the end of the intervention.

CONCLUSIONS

Overall, as the 8-week synbiotic consumption compared with placebo had insignificant-reducing effects on glycemic profile, IGF-1 and sex hormones among overweight and obese postmenopausal BCSs, synbiotics may exert considerable beneficial consequences, which need to be further assessed in future clinical trials.

TRIAL REGISTRATION

IRCT, IRCT2015090223861N1. Registered 02 February 2017, http://www.irct.ir: IRCT2015090223861N1.

Role of gut microbiota in type 2 diabetes pathophysiology

A substantial body of literature has provided evidence for the role of gut microbiota in metabolic diseases including type 2 diabetes. However, reports vary regarding the association of particular taxonomic groups with disease. In this systematic review, we focused on the potential role of different bacterial taxa affecting diabetes. We have summarized evidence from 42 human studies reporting microbial associations with disease, and have identified supporting preclinical studies or clinical trials using treatments with probiotics. Among the commonly reported findings, the genera of Bifidobacterium, Bacteroides, Faecalibacterium, Akkermansia and Roseburia were negatively associated with T2D, while the genera of Ruminococcus, Fusobacterium, and Blautia were positively associated with T2D. We also discussed potential molecular mechanisms of microbiota effects in the onset and progression of T2D.

Probiotics for glycemic control in patients with type 2 diabetes mellitus: protocol for a systematic review

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a major public health problem worldwide. It is characterized by the increased concentration of glucose in the blood and leads to damage of the body system, especially blood vessels and nerves. Lifestyle modification is often combined with anti-diabetic therapy as the standard of care for T2DM to maintain the proper blood glucose and to prevent long-term diabetic complications. The role of probiotics in improving glycemic control has been investigated in several randomized controlled trials (RCTs). Previous systematic reviews and meta-analyses, including different sets of trials have concluded an overall beneficial effect of probiotics in patients with T2DM. At least two RCTs with a longer treatment duration have been published since the publication of existing reviews.

METHODS

We will conduct a systematic review of RCTs that evaluated the effectiveness and safety of probiotics for glycemic control in T2DM patients. Primary outcomes are fasting blood glucose and glycosylated hemoglobin (A1c). Secondary outcomes are plasma insulin, blood lipid profile, adverse events, and cost associated with the intervention and hospital visits. We will search PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, and trial registries. Two reviewers will independently screen titles and abstracts, review full texts, extract information, and assess the risk of bias. We will summarize the results both qualitatively and statistically. We will use random-effects model for meta-analysis.

DISCUSSION

This systematic review aims to examine whether probiotics are effective and safe for glycemic control in T2DM patients. Evidence generated from this review will inform clinical and public health practice and future research.

SYSTEMATIC REVIEW REGISTRATION

CRD42019121682.

Impact of bacterial probiotics on obesity, diabetes and non-alcoholic fatty liver disease related variables: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To systematically review the effect of oral intake of bacterial probiotics on 15 variables related to obesity, diabetes and non-alcoholic fatty liver disease.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, EMBASE and COCHRANE from 1990 to June 2018.

ELIGIBILITY CRITERIA

Randomised controlled trials (≥14 days) excluding hypercholesterolaemia, alcoholic liver disease, polycystic ovary syndrome and children <3 years.

RESULTS

One hundred and five articles met inclusion criteria, representing 6826 subjects. In overweight but not obese subjects, probiotics induced improvements in: body weight (k=25 trials, d=-0.94 kg mean difference, 95% CI -1.17 to -0.70, I²=0.0%), body mass index (k=32, d=-0.55 kg/m², 95% CI -0.86 to -0.23, I²=91.9%), waist circumference (k=13, d=-1.31 cm, 95% CI -1.79 to -0.83, I²=14.5%), body fat mass (k=11, d=-0.96 kg, 95% CI -1.21 to -0.71, I²=0.0%) and visceral adipose tissue mass (k=5, d=-6.30 cm², 95% CI -9.05 to -3.56, I²=0.0%). In type 2 diabetics, probiotics reduced fasting glucose (k=19, d=-0.66 mmol/L, 95% CI -1.00 to -0.31, I²=27.7%), glycated haemoglobin (k=13, d=-0.28 pp, 95% CI -0.46 to -0.11, I²=54.1%), insulin (k=13, d=-1.66 mU/L, 95% CI -2.70 to -0.61, I²=37.8%) and homeostatic model of insulin resistance (k=10, d=-1.05 pp, 95% CI -1.48 to -0.61, I²=18.2%). In subjects with fatty liver diseases, probiotics reduced alanine (k=12, d=-10.2 U/L, 95% CI -14.3 to -6.0, I²=93.50%) and aspartate aminotransferases (k=10, d=-9.9 U/L, 95% CI -14.1 to -5.8, I²=96.1%). These improvements were mostly observed with bifidobacteria (Bifidobacterium breve, B. longum), Streptococcus salivarius subsp. thermophilus and lactobacilli (Lactobacillus acidophilus, L. casei, L. delbrueckii) containing mixtures and influenced by trials conducted in one country.

CONCLUSIONS

The intake of probiotics resulted in minor but consistent improvements in several metabolic risk factors in subjects with metabolic diseases.

TRIAL REGISTRATION NUMBER

CRD42016033273.

The Effect of Probiotic Yogurt on Glycemic Control in Type 2 Diabetes or Obesity: A Meta-Analysis of Nine Randomized Controlled Trials

Probiotic yogurt is suggested as a nutritional approach in type 2 diabetes (T2D) and obesity. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the effects of probiotic yogurt on glycemic outcomes in T2D or obesity. The databases used to search for RCTs included Medline and Scopus. The RCTs were eligible if outcomes included selected glycemic markers. In nine eligible trials, 237 and 235 subjects were in treatment (probiotic yogurt) and control (mostly conventional yogurt) groups, respectively. There was no significant difference for pooled unstandardized mean difference (USMD) hemoglobin A1c (HbA1c) by probiotic yogurt compared with the control in T2D (USMD: -0.366; 95% CI: -0.755, 0.024, p = 0.066) and obesity (USMD: 0.116, 95% CI: -0.007, 0.238, p = 0.065). Similarly, there were no effects of probiotic yogurt on fasting blood glucose, fasting insulin, or insulin resistance (estimated by homeostatic model assessment of insulin resistance (HOMA-IR)) in either T2D or obesity. In conclusion, the present meta-analysis has not demonstrated the benefits of consuming probiotic compared with conventional yogurt for improving glucose control in patients with diabetes or obesity. Larger trials are needed to verify the benefits of probiotic and/or conventional yogurt or other probiotic fermented milk (e.g., kefir) on glycemic markers in patients with diabetes and obesity.

Industry funding effect on positive results of probiotic use in the management of acute diarrhea: a systematized review

Several investigations have found that industry-funded studies tend to inform results favoring the sponsored products. The pressure to demonstrate that a drug or a product causes a favorable outcome may result in investigation biases from industry-funded research. One example of this could be found in the probiotic research funded by the industry. The aim of this study was to assess the effect of industry funding on positive outcomes of the use of probiotics in the management of acute diarrhea. A systematized review of clinical trials on the use of probiotics in the management of acute diarrhea was performed. The associations between the source of funding, clinical outcomes, probiotic genus, and quality of the study were assessed using the χ-test and Fisher's exact test. Sixty-six clinical trials were included; 27 were industry funded, 18 were nonindustry funded, and 21 did not disclose their funding source. There were 48 positive and 30 negative clinical outcomes. There was no significant association between the source of funding and clinical outcomes (P=0.491). No association between the rest of the studied variables and outcomes was observed either (P>0.05). In clinical trials on the use of probiotics in the management of acute diarrhea, the source of funding has no influence on positive clinical outcomes.

Novel perspectives on fermented milks and cardiometabolic health with a focus on type 2 diabetes

This review will explore the observational and mechanistic evidence supporting the hypothesis that fermented milk consumption has beneficial effects on metabolism. Live cultures in fermented dairy are thought to contribute to gut microbial balance, which is likely an instrumental mechanism that protects the host against gut dysbiosis and systemic inflammation associated with cardiometabolic diseases. Lactic acid bacteria (LAB) release bioactive metabolites, such as exopolysaccharides and peptides, that have the potential to exert a wide range of metabolic and regulatory functions. In particular, peptides derived from fermented dairy products are likely to exert greater cardiometabolic and anti-inflammatory effects than nonfermented dairy. It is hypothesized that LAB-derived bioactive peptides have the potential to protect the host against cardiometabolic diseases through antimicrobial actions and to effect changes in gene expression of glucose regulatory and anti-inflammatory signaling pathways. The peptides released through fermentation may explain some of the health effects of fermented dairy products on cardiometabolic disease risk observed in epidemiological studies, particularly type 2 diabetes; however, mechanisms have yet to be explored in detail.

Influence of Probiotics Administration on Gut Microbiota Core: A Review on the Effects on Appetite Control, Glucose, and Lipid Metabolism

An increasing number of studies has shown that dietary probiotics exert beneficial health effects in both humans and animals. It is well established that gut microbiota play a pivotal role in regulating host metabolism, and a growing number of studies has elucidated that probiotics positively interfere with gut microbiota. Accumulating evidence shows that probiotics, through their metabolic activity, produce metabolites that in turn contribute to positively affect host physiology. For these reasons, probiotics have shown significant potential as a therapeutic tool for a diversity of diseases, but the mechanisms through which probiotics act has not been fully elucidated yet. The goal of this review was to provide evidence on the effects of probiotics on gut microbiota changes associated with host metabolic variations, specifically focusing on feed intake and lipid and glucose metabolism. In addition, we review probiotic interaction with the gut microbiota. The information collected here will give further insight into the effects of probiotics on the gut microbiota and their action on metabolite release, energy metabolism, and appetite. This information will help to improve knowledge to find better probiotic therapeutic strategies for obesity and eating disorders.

Altered Gut Microbiota in Type 2 Diabetes: Just a Coincidence?

PURPOSE OF REVIEW

In the last decade many studies have suggested an association between the altered gut microbiota and multiple systemic diseases including diabetes. In this review, we will discuss potential pathophysiological mechanisms, the latest findings regarding the mechanisms linking gut dysbiosis and type 2 diabetes (T2D), and the results obtained with experimental modulation of microbiota.

RECENT FINDINGS

In T2D, gut dysbiosis contributes to onset and maintenance of insulin resistance. Different strategies that reduce dysbiosis can improve glycemic control. Evidence in animals and humans reveals differences between the gut microbial composition in healthy individuals and those with T2D. Changes in the intestinal ecosystem could cause inflammation, alter intestinal permeability, and modulate metabolism of bile acids, short-chain fatty acids and metabolites that act synergistically on metabolic regulation systems contributing to insulin resistance. Interventions that restore equilibrium in the gut appear to have beneficial effects and improve glycemic control. Future research should examine in detail and in larger studies other possible pathophysiological mechanisms to identify specific pathways modulated by microbiota modulation and identify new potential therapeutic targets.

Effect of alive probiotic on insulin resistance in type 2 diabetes patients: Randomized clinical trial

BACKGROUND

Probiotics have beneficial effect on obesity related disorders in animal models. Despite a large number of animal data, randomized placebo-controlled trials (RCT) concluded that probiotics have a moderate effect on glycemic control-related parameters. However, effect of probiotics on insulin resistance are inconsistent.

AIM

In a double-blind single center RCT, effect of alive multistrain probiotic vs. placebo on insulin resistance in type 2 diabetes patient were assessed.

METHODS

A total of 53 patients met the criteria for inclusion. They were randomly assigned to receive multiprobiotic "Symbiter" (concentrated biomass of 14 probiotic bacteria genera Bifidobacterium, Lactobacillus, Lactococcus, Propionibacterium) or placebo for 8-weeks administered as a sachet formulation. The primary main outcome was the change HOMA-IR (homeostasis model assessment-estimated insulin resistance) which calculated using Matthews et al.'s equation. Secondary outcomes were the changes in glycemic control-related parameters, anthropomorphic variables and cytokines.

RESULTS

Supplementation with alive multiprobiotic for 8 weeks was associated with significant reduction of HOMA-IR from 6.85 ± 0.76 to 5.13 ± 0.49 (p = 0.047), but remained static in the placebo group. With respect to our secondary outcomes, HbA1c insignificant decreased by 0.09% (p = 0.383) and 0.24% (p = 0.068) respectively in placebo and probiotics groups. However, in probiotic responders (n = 22, patient with decrease in HOMA-IR) after supplementation a significant reduction in HbA1c by 0.39% (p = 0.022) as compared to non-responders was observed. In addition, from markers of chronic systemic inflammatory state only TNF-α and IL-1β changes significantly after treatment with probiotics.

CONCLUSION

Probiotic therapies modestly improved insulin resistance in patients with type 2 diabetes.

The beneficial effects of probiotic administration on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial

BACKGROUND

This study was conducted to evaluate the effects of probiotic supplementation on wound healing and metabolic status in subjects with diabetic foot ulcer (DFU).

METHODS

This randomized, double-blind, placebo-controlled trial was conducted among 60 subjects (aged 40-85 years old) with grade 3 diabetic foot ulcer. Individuals were randomly divided into 2 groups (30 subjects each group) to receive either probiotic or placebo daily for 12 weeks.

RESULTS

After the 12-week intervention, compared with the placebo, probiotic supplementation led to significant reductions in ulcer length (-1.3 ± 0.9 vs. -0.8 ± 0.7 cm, P = .01), width (-1.1 ± 0.7 vs. -0.7 ± 0.7 cm, P = .02), and depth (-0.5 ± 0.3 vs. -0.3 ± 0.3 cm, P = .02). Furthermore, significant reductions in fasting plasma glucose (-29.6 ± 30.3 vs. -5.8 ± 39.8 mg/dL, P = .01), serum insulin concentrations (-4.3 ± 7.9 vs. +0.4 ± 8.5 μIU/mL, P = .03), and haemoglobin A1c (-0.6 ± 0.5 vs. -0.2 ± 0.4%, P = .003) and a significant rise in the quantitative insulin sensitivity check index (+0.01 ± 0.01 vs. -0.01 ± 0.02, P = .003) were seen following supplementation of probiotic compared with the placebo. Additionally, compared with the placebo, probiotic supplementation resulted in significant decreases in serum total cholesterol (-4.8 ± 16.1 vs. +7.0 ± 27.1 mg/dL, P = .04), high-sensitivity C-reactive protein (-9.0 ± 14.7 vs. -1.7 ± 8.6 mg/L, P = .02), plasma malondialdehyde (-0.8 ± 0.8 vs. -0.2 ± 0.8 μmol/L, P = .001), and significant increases in plasma nitric oxide (+6.2 ± 8.2 vs. +0.8 ± 8.0 μmol/L, P = .01) and total antioxidant capacity concentrations (+179.3 ± 97.2 vs. -85.1 ± 203.4 mmol/L, P < .001).

CONCLUSIONS

Overall, probiotic supplementation for 12 weeks among subjects with diabetic foot ulcer had beneficial effects on ulcer size, glycaemic control, total cholesterol, high-sensitivity C-reactive protein, plasma nitric oxide, total antioxidant capacity, and malondialdehyde levels.

Microbial Regulation of Glucose Metabolism and Insulin Resistance

Type 2 diabetes is a combined disease, resulting from a hyperglycemia and peripheral and hepatic insulin resistance. Recent data suggest that the gut microbiota is involved in diabetes development, altering metabolic processes including glucose and fatty acid metabolism. Thus, type 2 diabetes patients show a microbial dysbiosis, with reduced butyrate-producing bacteria and elevated potential pathogens compared to metabolically healthy individuals. Furthermore, probiotics are a known tool to modulate the microbiota, having a therapeutic potential. Current literature will be discussed to elucidate the complex interaction of gut microbiota, intestinal permeability and inflammation leading to peripheral and hepatic insulin resistance. Therefore, this review aims to generate a deeper understanding of the underlying mechanism of potential microbial strains, which can be used as probiotics.

Probiotic supplementation and the effects on weight loss, glycaemia and lipid profiles in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial

The aim of the current study was to assess the effects of probiotic supplementation on weight loss, glycaemia and lipid profiles in women with polycystic ovary syndrome (PCOS). In a randomized, double-blind, placebo-controlled trial, 60 women with PCOS were randomized to receive probiotic capsule (n = 30) or placebo (n = 30) for 12 weeks. Consumption of probiotic supplements resulted in a significant reduction in weight (-0.5 ± 0.4 vs. +0.1 ± 1.0 kg, p = 0.004) and BMI (-0.2 ± 0.2 vs. +0.03 ± 0.4 kg/m2, p = 0.004) compared with the placebo. In addition, compared with the placebo, probiotic administration was associated with a significant decrease in fasting plasma glucose (-2.4 ± 8.4 vs. +2.1 ± 7.0 mg/dL, p = 0.02), serum insulin concentrations (-2.0 ± 5.8 vs. +1.6 ± 5.0 μIU/mL, p = 0.01), homoeostasis model of assessment-insulin resistance (-0.5 ± 1.4 vs. +0.3 ± 1.1, p = 0.01), homoeostatic model assessment-beta cell function (-7.5 ± 22.3 vs. +6.3 ± 21.7, p = 0.01), serum triglycerides (-13.3 ± 51.3 vs. +13.6 ± 37.1 mg/dL, p= 0.02) and a significant increase in quantitative insulin sensitivity check index (QUICKI) (+0.006 ± 0.01 vs. -0.005 ± 0.02, p = 0.01). When we adjusted the analysis for baseline values of biochemical parameters, age and baseline BMI, except for QUICKI (p = 0.08), other findings did not alter. We found that probiotic supplementation among PCOS women for 12 weeks had favourable effects on weight loss, markers of insulin resistance, triglycerides and VLDL-cholesterol concentrations.

Probiotics, prebiotics, synbiotics and insulin sensitivity

Animal studies indicate that the composition of gut microbiota may be involved in the progression of insulin resistance to type 2 diabetes. Probiotics and/or prebiotics could be a promising approach to improve insulin sensitivity by favourably modifying the composition of the gut microbial community, reducing intestinal endotoxin concentrations and decreasing energy harvest. The aim of the present review was to investigate the effects of probiotics, prebiotics and synbiotics (a combination of probiotics and prebiotics) on insulin resistance in human clinical trials and to discuss the potential mechanisms whereby probiotics and prebiotics improve glucose metabolism. The anti-diabetic effects of probiotics include reducing pro-inflammatory cytokines via a NF-κB pathway, reduced intestinal permeability, and lowered oxidative stress. SCFA play a key role in glucose homeostasis through multiple potential mechanisms of action. Activation of G-protein-coupled receptors on L-cells by SCFA promotes the release of glucagon-like peptide-1 and peptide YY resulting in increased insulin and decreased glucagon secretion, and suppressed appetite. SCFA can decrease intestinal permeability and decrease circulating endotoxins, lowering inflammation and oxidative stress. SCFA may also have anti-lipolytic activities in adipocytes and improve insulin sensitivity via GLUT4 through the up-regulation of 5'-AMP-activated protein kinase signalling in muscle and liver tissues. Resistant starch and synbiotics appear to have favourable anti-diabetic effects. However, there are few human interventions. Further well-designed human clinical studies are required to develop recommendations for the prevention of type 2 diabetes with pro- and prebiotics.

Gut microbiota and probiotics: Focus on diabetes mellitus

The characterization of gut microbiota has become an important area of research in several clinical conditions, including type 2 diabetes (T2DM). Changes in the composition and/or metabolic activity of the gut microbiota can contribute to human health. Thus, this review discusses the effects of probiotics and gut microbiota on metabolic control in these individuals. Relevant studies were obtained from electronic databases such as PubMed/Medline and ISI Web of Science. The main probiotics used in these studies belonged to the genera Lactobacillus and Bifidobacterium. The authors found seven randomized placebo-controlled clinical trials and 13 experimental studies directly related to the effect of probiotics on metabolic control in the context of T2DM. The hypothesis that gut microbiota plays a role in the development of diabetes indicates an important beginning, and the potential of probiotics to prevent and reduce the severity of T2DM is better observed in animal studies. In clinical trials, the use of probiotics in glycemic control presented conflicting results, and only few studies have attempted to evaluate factors that justify metabolic changes, such as markers of oxidative stress, inflammation, and incretins. Thus, further research is needed to assess the effects of probiotics in the metabolism of diabetic individuals, as well as the main mechanisms involved in this complex relationship.

Multiple effects of probiotics on different types of diabetes: a systematic review and meta-analysis of randomized, placebo-controlled trials

BACKGROUND

A systematic review and meta-analysis was designed to evaluate the effect of probiotics on diabetes and its associated risk factors.

METHODS

We systematically searched the Cochrane Library, PubMed, EMBASE and Web of Science to June 2016. We also hand-searched the citation lists of included studies and previously identified systematic reviews to identify further relevant trials. Our primary outcome variables included glucose, glycated hemoglobin (HbA1c) and insulin. The pooled standardized mean difference was used to compare the effect between the probiotics and controlled groups, and the pooled standardized mean difference effect size with a 95% confidence interval (CI) was estimated using a random-effect model. Heterogeneity was assessed with Cochran's Q and Higgins I2 tests. Two reviewers assessed trial quality and extracted data independently. The analysis and bias for each included study was performed and assessed using Review Manager 5.2.

RESULTS

Eighteen randomized, placebo-controlled studies (n=1056 participants, 527 consuming probiotics, 529 not consuming probiotics) were included for analysis. Comparing the probiotics groups with the control groups, there were statistically significant pooled standardized mean differences on the reduction of glucose (-0.61, 95% CI -0.98, -0.24; p=0.001), insulin (-0.49, 95% CI -0.93, -0.04; p=0.03) and HbA1c (-0.39, 95% CI -0.60, -0.19%; p=0.0001). Subgroup analysis also indicated statistical significance on the reduction of low-density lipoprotein cholesterol (LDL-C) in non-type 2 diabetes (non-T2DM) mellitus patients with diabetes, for the pooled standardized mean difference was -0.29 (95% CI -0.54, -0.04; p=0.02).

CONCLUSIONS

Probiotics may have beneficial effects on the reduction of glucose, insulin and HbA1c for diabetes, especially for T2DM mellitus patients.

Mismatch between Probiotic Benefits in Trials versus Food Products

Probiotic food products contain a variety of different bacterial strains and may offer different health effects. The objective was to document the prevalence and dosage of probiotic strains in the Canadian food supply and to review the literature investigating these strains in order to understand what health benefits these products may offer. The Food Label Information Program was used to identify probiotic-containing products in the food supply. PubMed, Web of Science, and Embase were searched for randomized controlled trials that tested the health effects of these strains in humans. There were six probiotic strains/strain combinations identified in the food supply. Thirty-one studies investigated these strains and found that they are associated with decreased diarrhea and constipation, improved digestive symptoms, glycemic control, antioxidant status, blood lipids, oral health, and infant breastfeeding outcomes, as well as enhanced immunity and support for Helicobacter pylori eradication. There were a limited number of studies investigating these strains. Many studies were funded by the food industry and tested dosages that were up to twenty-five times the dosage found in most food products. Probiotic food products could have health benefits not currently reported on their labels. However, many dosages are too low to provide the benefits demonstrated in clinical trials. Further research is needed to enable more effective use of these functional foods.

Effect of probiotics and synbiotics on blood glucose: a systematic review and meta-analysis of controlled trials

PURPOSE

High fasting blood glucose (FBG) can lead to chronic diseases such as diabetes mellitus, cardiovascular and kidney diseases. Consuming probiotics or synbiotics may improve FBG. A systematic review and meta-analysis of controlled trials was conducted to clarify the effect of probiotic and synbiotic consumption on FBG levels.

METHODS

PubMed, Scopus, Cochrane Library, and Cumulative Index to Nursing and Allied Health Literature databases were searched for relevant studies based on eligibility criteria. Randomized or non-randomized controlled trials which investigated the efficacy of probiotics or synbiotics on the FBG of adults were included. Studies were excluded if they were review articles and study protocols, or if the supplement dosage was not clearly mentioned.

RESULTS

A total of fourteen studies (eighteen trials) were included in the analysis. Random-effects meta-analyses were conducted for the mean difference in FBG. Overall reduction in FBG observed from consumption of probiotics and synbiotics was borderline statistically significant (-0.18 mmol/L 95 % CI -0.37, 0.00; p = 0.05). Neither probiotic nor synbiotic subgroup analysis revealed a significant reduction in FBG. The result of subgroup analysis for baseline FBG level ≥7 mmol/L showed a reduction in FBG of 0.68 mmol/L (-1.07, -0.29; ρ < 0.01), while trials with multiple species of probiotics showed a more pronounced reduction of 0.31 mmol/L (-0.58, -0.03; ρ = 0.03) compared to single species trials.

CONCLUSION

This meta-analysis suggests that probiotic and synbiotic supplementation may be beneficial in lowering FBG in adults with high baseline FBG (≥7 mmol/L) and that multispecies probiotics may have more impact on FBG than single species.