Probiotic therapy, a novel and efficient adjuvant approach to improve glycemic status: An umbrella meta-analysis

Effectiveness of different gums on modulating of glycemic indices in adults: a systematic review and meta-analysis

Background

Functional foods have been widely used as the anti-diabetic agents worldwide. Existing studies presented conflicting results of anti-hyperglycemic properties of gums. This systematic review and meta-analysis study evaluated the existing trials and determined the efficacy of different gums on glycemic indices.

Method

Systematic search was performed on four main databases (PubMed, Scopus, Embase, Web of Science) by November 2023 using medical subject headings. The meta-analyses were conducted on the findings of the studies of guar gum supplementation on glycemic indices including fasting blood glucose (FBG) and HbA1c (hemoglobinA1c) and systematic review studies include the effect of xanthan gum, arabic gum, bitter almond gum, flaxseed gum, oat gum, gellan gum, locust been gum, tragacanth gum, and karaya gum on fasting plasma insulin, postprandial plasma glucose, HbA1c and Homeostatic Model Assessment for Insulin Resistance (HOMA - IR).

Results

Totally, 42 studies were included in this systematic review. Regarding guar gum, xanthan gum, and Arabic gum, most of included studies in our investigation showed that guar gum can be considered as an anti-hyperglycemic agent. Results on other types of gums including bitter almond gum, flaxseed gum, oat gum, gellan gum, locust been gum, tragacanth gum, and karaya gum are limited and exact interpretation cannot be obtained. In meta-analysis on 17 studies of guar gum, it was identified guar gum had a non-significant decrease of 3.02 mg/dl (Mean difference: -3.02, CI 95%: -7.60, 1.56) on the fasting glucose and 0.23 (Mean difference: -0.23, CI 95%: -0.63, 0.17) on HbA1c.

Conclusion

Modification of food processing using gums may be a promising strategy to help modulate glycemic indices. More studies with larger sample size are needed, both with acute and long-term interventions to clarify this issue.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-024-01541-0.

The impact of probiotics therapy on cognitive and metabolic characteristics in patients with cognitive impairment: An umbrella review of meta-analysis of randomized controlled trials

BACKGROUND

While existing meta-analysis suggest that probiotic therapies may enhance cognitive functions and influence metabolic characteristics, the findings have been inconclusive. In light of these discrepancies, our study undertakes an umbrella review to more precisely determine the aggregate effects and rigorously evaluate the credibility and quality of evidence.

METHODS

We conducted a systematic search across seven databases, including PubMed, Embase, the Cochrane Library, ProQuest, Web of Science, CINAHL, and Scopus, from their inception to June 20, 2024. We utilized the AMSTAR-2 tool to evaluate the quality of the meta-analyses and applied the GRADE system to rate the quality of the evidence. We estimated the final effect sizes (ESs) along with their 95% confidence intervals (CI) and performed both sensitivity and subgroup analyses to explore the sources of heterogeneity.

RESULTS

Among the 314 articles identified in our search, 13 meta-analysis that met the criteria were included in the study. The quality of the evidence in these studies was graded from high to very low. Our results demonstrate that probiotic treatment significantly enhances cognitive function in patients (ESSMD = 0.39, 95%CI: 0.19 to 0.59, p < 0.001). Moreover, probiotic treatment notably decreased level of serum malondialdehyde (MDA), insulin resistance as detected by homeostasis model assessment method (HOMA-IR) and high-sensitivity C-reactive protein (hs-CRP) (p < 0.001). Conversely, probiotic treatment did not significantly impact triglycerides and very-low-density lipoprotein (VLDL) in patients (p > 0.05).

CONCLUSION

Although preliminary evidence indicated that probiotic therapy may positively impact cognitive function, MDA, HOMA-IR, and hs-CRP, the overall quality of the existing evidence is insufficient to provide strong support. Therefore, future research must employ more rigorous designs or initiate larger clinical trials to produce more compelling evidence to further validate the efficacy of probiotic therapy on cognitive function of patients with cognitive dysfunction.

Impact of Probiotics on Triglyceride Level After Bariatric Surgery: A Trial Sequential Analysis

This meta-analysis and trial sequential analysis (TSA) investigated the effects of probiotic supplementation on triglyceride levels in patients after bariatric surgery. A comprehensive literature search identified seven randomized controlled trials involving 411 participants. The meta-analysis revealed a significant reduction in triglyceride levels favoring probiotic supplementation (mean difference =  - 18.46 mg/dL, 95% confidence interval [- 29.73, - 7.2], p = 0.001) with no heterogeneity (I2 = 0%). The observed reduction in triglycerides (18.46 mg/dL) exceeds the reported minimal clinically important difference (MCID) threshold for triglycerides (i.e., 7.97 mg/dL), suggesting clinically meaningful improvements. TSA confirmed that sufficient evidence has been accumulated to support the effect of probiotics on triglycerides, with the cumulative Z-curve crossing the required information size of 313 participants. These findings suggest that probiotic supplementation could be a valuable adjunct therapy for managing lipid profiles in patients undergoing bariatric surgery. Future research should focus on optimizing probiotic interventions, including identifying the most effective strains, dosages, and duration of supplementation.

The effects of purslane (Portulaca oleracea) on C-reactive protein, lipid profile, and glycemic control in patients with type 2 diabetes mellitus: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials

Although numerous trials have demonstrated the benefits of purslane on patients with type 2 diabetes mellitus (T2DM), the results of some studies reject such effect. We elucidated the influence of purslane on c-reactive protein (CRP), lipid profile, and glycemic control in patients with T2DM. We conducted a systematic search on Web of Sciences, Scopus, the Cochrane Library, PubMed, and Embase, to identify studies published from their inception to February 10, 2024. The random effect model was used to calculate the combined effect, the weighted mean differences (WMDs) and its 95 % confidence interval (CI). Purslane supplementation significantly reduced fasting blood glucose (FBG) levels (WMD: -15.01; 95 % CI: -25.31, -4.71, p= 0.004), total cholesterol (TC) (WMD: -17.75; 95 % CI: -26.06, -9.45; p< 0.001), triglyceride (TG) (WMD: -21.30; 95 % CI: -32.59, -10.00; p< 0.001), low-density lipoprotein cholesterol (LDL-C) (WMD: -6.10; 95 % CI: -9.52, -2.68; p< 0.001), and CRP levels (WMD: -1.44; 95 % CI: -2.25, -0.63; p< 0.001), and increased high-density lipoprotein cholesterol (HDL-C) (WMD: 6.17; 95 % CI: 2.53, 9.80; p< 0.001). Also, purslane did not significant effect on serum levels of insulin, hemoglobin A1C (HbA1c), and homeostatic model Assessment for insulin resistance (HOMA-IR). The results of our study showed that purslane supplementation improved FBG, and lipid profile levels, but did not affect HOMA-IR, insulin, and HbA1c levels. However, high-quality trials are needed to approve our results.

Effects of saffron (Crocus sativus L.) supplementation on cardiometabolic Indices in diabetic and prediabetic overweight patients: a systematic review and meta-analysis of RCTs

BACKGROUND

The incidence of diabetes mellitus (DM) is increasing worldwide, and there is growing interest in the potential use of natural compounds as an alternative treatment for managing DM. Several research studies have investigated the impact of saffron consumption on managing and improving metabolic profiles in patients with DM, and they have shown promising results.

OBJECT

The study aims to systematically review and perform a meta-analysis to evaluate the potential effects of saffron and its extract on cardiometabolic indicators in diabetic and prediabetic overweight patients.

METHODS

We conducted a comprehensive systematic review and meta-analysis, searching PubMed, Scopus, Web of Science, Embase, and Google Scholar for all relevant studies published before April 20, 2024. We extracted weighted (WMD) or standardized (SMD) mean differences (before-after) and 95% confidence intervals (95%CI) of the outcomes and conducted meta-analyses using R. The study protocol was registered in PROSPERO (CRD42024538380).

RESULTS

Out of the studies screened, 15 RCTs were selected for inclusion in the systematic review and meta-analysis. These studies collectively involved 869 participants, 438 in the intervention group and 431 in the control group. Notably, our results showed that saffron supplementation led to significant changes in FBS (MD: - 8.75 mg/dL, 95% CI [- 14.75; - 2.76], P < 0.01), HbA1C (MD: - 0.34%, 95% CI [- 0.39; - 0.9], P < 0.01), TG (MD: - 13.28 mg/dL, 95% CI [- 22.82; - 3.75], P < 0.01), SBP (MD: - 5.33 mmHg, 95% CI [- 8.99-1.67], P = 0.04), DBP (MD: - 1.02 mmHg, 95% CI [- 3.91; 1.86], P = 0.03), AST (MD: - 1.32 IU/L, 95% CI [- 1.72, - 0.93], P < 0.01) levels in T2DM patients compared to placebo or no supplementation, indicating its potential as a therapeutic intervention. However, there was no significant effect on Insulin secretion (MD: - 0.15 µU/ml, 95% CI [- 2.1763; 1.8689], P = 0.88), HOMA (MD: - 0.35%, 95% CI [- 1.34;0.63], P = 0.48), TC (MD: - 4.86 mg/dL, 95% CI [- 9.81-0.09], P = 0.54), HDL (MD: 0.18 mg/dL, 95% CI [- 0.93; 1.29], P = 0.74), LDL (MD: - 1.77 mg/dL, 95% CI [- 5.99-2.45], P = 0.41), TNF-α (MD: - 0.34 pg/mL, 95% CI [- 0.99-0.30], P = 0.29), creatinine (MD: 2.83 mg/dL, 95% CI [2.29, 3.37], P = 0.31) and BUN (MD: - 0.44 mg/dL, 95% CI [- 1.43, 0.55], P = 0.38).

CONCLUSION

Saffron may improve specific CMI indices in overweight patients with diabetes or prediabetes, including significant reductions in FBS, HbA1C, TG, SBP, and AST. However, it did not significantly affect HDL, TC, LDL, insulin secretion, HOMA, DBP, TNF-α, ALT, Cr, or BUN. Further research with more trials and extended follow-up periods is needed to confirm and expand these findings.

The effect of probiotics on gestational diabetes mellitus: an umbrella meta-analysis

BACKGROUND

Prior studies indicated the positive effects of probiotics on glycemic regulation in patients with gestational diabetes mellitus (GDM). Nonetheless, the results remain inconclusive. To address this, we conducted an umbrella meta-analysis to evaluate the impact of probiotics on glycemic indicators in GDM.

METHODS

A comprehensive search was conducted on the PubMed and Scopus databases to identify all relevant meta-analyses of randomized clinical trials published until July 2024. The outcomes included serum hemoglobin A1C (HbA1c), fasting blood insulin (FBI), fasting blood sugar (FBS), homeostatic model assessment for insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), homeostatic model assessment of beta cell function (HOMA-B), C-peptide, and oral glucose tolerance test (OGTT). Standardized mean difference (SMD) was used to test the effects.

RESULTS

In total, 27 studies, comprising 33,378 participants, were included in the analysis. Probiotics resulted in a significant decrease in FBS (SMD: -0.39, 95% CI: -0.56 to -0.23), especially when administered for ≤ 7 weeks. Significant reductions were also observed in FBI (SMD: -1.99, 95% CI: -2.41 to -1.58), HOMA-IR (SMD: -0.61, 95% CI: -0.72 to -0.50), and HOMA-B (SMD: -24.58, 95% CI: -30.59 to -18.56). Moreover, supplementation with probiotics significantly improved QUICKI (SMD: 0.007, 95% CI: 0.004 to 0.01). There was significant evidence of heterogeneity and publication bias. No significant effects were observed on 1-h OGTT, 2-h OGTT, HbA1c, and C-peptide. No dose-specific effect was observed.

CONCLUSIONS

Supplementation with probiotics could improve glycemic control in women with GDM. The effects of probiotics on HOMA-IR, HOMA-B, and fasting insulin were clinically important, while, their effect on FBS was not clinically important.

The effect of different dietary restriction on weight management and metabolic parameters in people with type 2 diabetes mellitus: a network meta-analysis of randomized controlled trials

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a globally prevalent chronic condition. Individuals with T2DM are at increased risk of developing complications associated with both macrovascular and microvascular pathologies. These comorbidities reduce patient quality of life and increase mortality. Dietary restriction is a principal therapeutic approach for managing T2DM. This study assessed the effects of various dietary regimens on body weight and metabolic profiles in T2DM patients, aiming to determine the most beneficial interventions for enhancing clinical outcomes and overall well-being.

METHODS

We conducted a literature search in PubMed, Embase, and Web of Science from 2003 to April 15, 2024. The risk of bias was assessed via the Revised Cochrane risk-of-bias tool for randomized trials (RoB2). The certainty of the evidence was appraised via the confidence in network meta-analysis (CINeMA) framework. Intermittent fasting (IF) was directly compared with continuous energy restriction (CER) via Review Manager 5.4. Network meta-analysis was statistically assessed via R Studio 4.3.3 and STATA 14.0.

RESULTS

Eighteen studies involving 1,658 participants were included. The network meta-analysis indicated that intermittent energy restriction, the twice-per-week fasting, time-restricted eating, fasting-mimicking diets (FMD), and CER interventions were more effective than conventional diets. Direct comparisons revealed that IF was as effective as CER for reducing glycated haemoglobin A1c, body weight, and body mass index. The results of the cumulative ranking analysis demonstrated that FMD had the greatest combined intervention effect, followed by TRE in terms of overall effectiveness.

CONCLUSIONS

Both IF and CER exert positive influences on weight control and metabolic profile enhancement in individuals with T2DM, with FMD as part of IF demonstrating the greatest impact. To substantiate these findings, more rigorous randomized controlled trials that directly compare the effects of the different IF regimens with one another and with the CER regimen are needed.

The effect of glucomannan supplementation on lipid profile in adults: a GRADE-assessed systematic review and meta-analysis

BACKGROUND

Glucomannan has been studied for various health benefits, but its effects on lipid profile in adults are not well understood. This meta-analysis aims to evaluate the impact of glucomannan supplementation on serum/plasma levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), Apo B1, Apo A1, APO-B/ A1 ratio, and LDL-C/ HDL-C in adults.

METHODS

A comprehensive search was conducted across Scopus, PubMed, Embase, and Web of Science from inception to June 2024 to identify randomized controlled trials (RCTs) assessing glucomannan supplementation on lipid profile in adults. Data were extracted and analyzed using random effects model to determine the standardized mean differences (SMDs) and 95% confidence intervals (CIs) for each biomarker.

RESULTS

Glucomannan supplementation significantly decreased TC (SMD: -3.299; 95% CI: -4.955, -1.664, P < 0.001; I 2 = 95.41%, P-heterogeneity < 0.001), LDL-C (SMD: -2.993; 95% CI: -4.958, -1.028; P = 0.006; I 2 = 95.49%, P-heterogeneity < 0.001), and Apo B1 (SMD: -2.2; 95% CI: -3.58, -0.82; P = 0.01). However, glucomannan did not alter the levels of TG (SMD: -0.119; 95% CI: -1.076, 0.837, P = 0.789; I 2 = 91.63%, P-heterogeneity < 0.001), Apo A1 (SMD: -0.48; 95% CI: -6.27, 5.32; P = 0.76), APO-B/ A1 ratio (SMD: -1.15; 95% CI: -2.91, 0.61; P = 0.11), and LDL-C/ HDL-C ratio (SMD: -2.2; 95% CI: -7.28, 2.87; P = 0.2).

CONCLUSIONS

Glucomannan supplementation has a beneficial effect on the level of TC and LDL-C.

The effect of synbiotics on liver enzymes, obesity indices, blood pressure, lipid profile, and inflammation in patients with non-alcoholic fatty liver: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Patients with non-alcoholic fatty liver disease (NAFLD) benefit from using synbiotics. However, findings from existing trials remain contentious. Therefore, this meta-analysis evaluated the effects of synbiotics on liver enzymes, blood pressure, inflammation, and lipid profiles in patients with NAFLD.

METHODS

We searched PubMed, Embase, Cochrane, Scopus, and Web of Science for randomized controlled trials (RCTs) regarding synbiotics supplementation in patients with NAFLD.

RESULTS

The meta-analysis revealed that synbiotics supplementation significantly improved liver enzymes (AST, WMD: -9.12 IU/L; 95 % CI: -13.19 to -5.05; ALT, WMD: -8.53 IU/L; 95 % CI: -15.07 to -1.99; GGT, WMD: -10.42 IU/L; 95 % CI: -15.19 to -5.65), lipid profile (TC, WMD: -7.74 mg/dL; 95 % CI: -12.56 to -2.92), obesity indices (body weight, WMD: -1.95 kg; 95 % CI: -3.69 to -0.22; WC, WMD: -1.40 cm; 95 % CI: -2.71 to -0.10), systolic blood pressure (SBP, WMD: -6.00 mmHg; 95 % CI: -11.52 to -0.49), and inflammatory markers (CRP, WMD: -0.69 mg/L; 95 % CI: -1.17 to -0.21; TNF-α, WMD: -14.01 pg/mL; 95 % CI: -21.81 to -6.20).

CONCLUSION

Overall, supplementation with synbiotics positively improved liver enzymes, obesity indices, and inflammatory cytokines in patients with NAFLD.

The effect of Nigella sativa supplementation on glycemic status in adults: An updated systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis of randomized controlled trials (RCTs) sought to evaluate the effects of Nigella sativa (N. sativa) consumption on glycemic index in adults. A systematic literature search up to December 2023 was completed in PubMed, Scopus, and Web of Science, to identify eligible RCTs. Random effects models were assessed based on the heterogeneity tests, and pooled data were determined as weighted mean differences with a 95 % confidence interval. Finally, a total of 30 studies were found to be eligible for this meta-analysis. The pooled results using random effects model indicated that N. sativa supplementation significantly reduced FBS (SMD: -1.71; 95 % CI: -2.11, -1.31, p <0.001; I2= 92.7 %, p-heterogeneity <0.001) and HA1c levels (SMD: -2.16; 95 % CI: -3.04, -1.29, p <0.001; I2= 95.7 %, p-heterogeneity <0.001) but not effect on insulin (SMD = 0.48; 95 % CI: -0.53, 1.48, P = 0.353; I2= 96.1 %, p-heterogeneity <0.001), and HOMA-IR (SMD: -0.56; 95 % CI: -1.47, 0.35, p=0.229; I2= 95.0 %, p-heterogeneity <0.001).Overall, the evidence supports the consumption of N. sativa to reduce FBS and HA1c levels. Additional research, featuring extended durations and robust study designs, is necessary to determine the ideal dosage and duration of N. sativa supplementation for achieving a positive impact on glycemic markers.

Preventive effect of probiotics on oral mucositis induced by anticancer therapy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Oral mucositis (OM) is a prevalent and painful complication in patients undergoing anticancer treatment, which significantly impacts patients' quality of life (QoL) and adherence to therapy. The use of oral probiotics as a preventive strategy for OM has shown promise, but the clinical evidence remains inconclusive. This meta-analysis of randomized controlled trials (RCTs) aims to evaluate the efficacy of probiotics in preventing OM caused by radiotherapy and/or chemotherapy.

METHODS

A comprehensive search of PubMed, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov was conducted up to January 31, 2024, to identify eligible RCTs. The primary outcomes were the incidences of severe OM and all-grade OM. Secondary outcomes included rates of anticancer treatment completion, clinical response, requirement for enteral nutrition, time course of OM, body weight loss, QoL, and adverse events (AEs). Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 12 RCTs involving 1,376 patients were included in the quantitative analysis. Probiotics administration significantly reduced the risk of severe OM (RR = 0.61, 95%CI: 0.53-0.72, P < 0.001) and all-grade OM (RR = 0.90, 95%CI: 0.82-0.98, P = 0.016) compared to the control group. Multi-strain probiotics formulations were more effective than single-strain probiotics in preventing severe OM (P = 0.011). There were no significant differences between the probiotics and control groups regarding anticancer treatment completion (RR = 1.03, 95%CI: 0.98-1.08, P = 0.198), clinical response to therapy (RR = 1.05, 95%CI: 0.94-1.17, P = 0.406), or the need for enteral nutrition (RR = 1.28, 95%CI: 0.49-3.35, P = 0.680). AEs related to probiotics were rare, with no serious AEs attributable to probiotics use.

CONCLUSIONS

Oral probiotics are both safe and effective in preventing and reducing the severity of OM in patients undergoing anticancer therapy. Multi-strain probiotics demonstrate superior efficacy compared to single-strain probiotics. Further research is warranted to confirm these findings and optimize probiotic treatment strategies for cancer patients.

The effect of synbiotic supplementation on plasma levels of advanced glycation end products and cardiovascular risk factors in hemodialysis patients: A double-blind clinical trial

There is increasing evidence supporting the relationship between imbalance of gut microbiota and development of chronic kidney and cardiovascular diseases. This study aimed to investigate the effect of synbiotic supplementation on plasma levels of advanced glycation end products (AGEs) and cardiovascular risk factors in hemodialysis (HD) patients. In this randomized, double-blind, placebo-controlled clinical trial, 36 HD patients were randomly allocated into two groups to receive two synbiotic supplements (n = 19) or placebo (n = 17) daily for 12 weeks. Levels of AGEs, fibrinogen, hemoglobin A1c (HbA1c), and other measures were assessed at the beginning and end of the study. The data were analyzed using independent t-tests, paired t-tests, and analysis of covariance (ANCOVA). At the end of the study, the plasma levels of AGEs increased significantly in both the synbiotic (p < .001) and control (p = .001) groups, but the difference between the groups was not significant (p = .272). Plasma levels of fibrinogen decreased specifically within the synbiotic group (p = .007), and a statistically significant disparity between the groups persisted at the study's conclusion (p = .016). The mean levels of blood urea nitrogen (BUN) decreased (p < .05) in both groups, but there was no difference between the two groups at the end of the study (p = .116). No significant differences were observed in other measured biomarkers. Synbiotic supplementation improved plasma fibrinogen and BUN levels in HD patients, but did not significantly improve AGEs and HbA1c. Further investigations are needed to investigate the effect of probiotics on AGEs in HD patients at different stages of kidney disease.

Efficacy of probiotics, prebiotics, and synbiotics on liver enzymes, lipid profiles, and inflammation in patients with non-alcoholic fatty liver disease: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

There is a contradiction in the use of microbiota-therapies, including probiotics, prebiotics, and synbiotics, to improve the condition of patients with nonalcoholic fatty liver disease (NAFLD). The aim of this review was to evaluate the effect of microbiota-therapy on liver injury, inflammation, and lipid levels in individuals with NAFLD.

METHODS

Using Pubmed, Embase, Cochrane Library, and Web of Science databases were searched for articles on the use of prebiotic, probiotic, or synbiotic for the treatment of patients with NAFLD up to March 2024.

RESULTS

Thirty-four studies involving 12,682 individuals were included. Meta-analysis indicated that probiotic, prebiotic, and synbiotic supplementation significantly improved liver injury (hepatic fibrosis, SMD = -0.31; 95% CI: -0.53, -0.09; aspartate aminotransferase, SMD = -0.35; 95% CI: -0.55, -0.15; alanine aminotransferase, SMD = -0.48; 95% CI: -0.71, -0.25; alkaline phosphatase, SMD = -0.81; 95% CI: -1.55, -0.08), lipid profiles (triglycerides, SMD = -0.22; 95% CI: -0.43, -0.02), and inflammatory factors (high-density lipoprotein, SMD = -0.47; 95% CI: -0.88, -0.06; tumour necrosis factor alpha, SMD = -0.86 95% CI: -1.56, -0.56).

CONCLUSION

Overall, supplementation with probiotic, prebiotic, or synbiotic had a positive effect on reducing liver enzymes, lipid profiles, and inflammatory cytokines in patients with NAFLD.

Is There Evidence to Support Probiotic Use for Healthy People?

Probiotics are typically marketed as foods and dietary supplements, categories for products intended to maintain health in generally healthy populations and which, unlike drugs, cannot claim to treat or cure disease. This review addresses the existing evidence that probiotics are beneficial to healthy people. Our approach was to perform a descriptive review of efficacy evidence that probiotics can prevent urinary, vaginal, gastrointestinal, and respiratory infections, and improve risk factors associated with cardiovascular health or reduce antibiotic use. Other endpoints such as mental, dental, or immune health were not specifically addressed. We concluded that there is sufficient evidence of efficacy and safety for clinicians and consumers to consider using specific probiotics for some indications - such as the use of probiotics to support gut function during antibiotic use or to reduce the risk of respiratory tract infections - for certain people. However, we did not find a sufficiently high level of evidence to support unconditional, population-wide recommendations for other preventive endpoints we reviewed for healthy people. Although evidence for some indications is suggestive of the preventive benefits of probiotics, additional research is needed.

The effects of probiotic supplementation and exercise training on liver enzymes and cardiometabolic markers in patients with non-alcoholic fatty liver disease: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver ailment worldwide, in which nonpharmacological strategies have a considerable role in the treatment. Probiotic supplementation as well as physical exercise can improve cardiometabolic parameters, but further research is needed to determine the effects of combined treatment versus exercise alone in managing NAFLD-associated biomarkers, primarily liver enzymes, lipid markers, and insulin resistance.

OBJECTIVES

This systematic review and meta-analysis aimed to evaluate the effects of probiotic supplementation, combined with exercise versus exercise alone, on liver enzymes and cardiometabolic markers in patients with NAFLD.

METHODS

A systematic review and meta-analysis of randomized clinical trials was performed by searching PubMed, Scopus, and Web of Science databases up to April 2024. The search was restricted to articles published in the English language and human studies. Random effects models were used to calculate weighted mean differences (WMD).

RESULTS

Pooled estimates (9 studies, 615 patients, intervention durations ranging from 8 to 48 weeks) revealed that probiotics plus exercise decreased aspartate transaminase (AST) [WMD=-5.64 U/L, p = 0.02], gamma-glutamyl transferase (GGT) [WMD=-7.09 U/L, p = 0.004], low-density lipoprotein (LDL) [WMD=-8.98 mg/dL, p = 0.03], total cholesterol (TC) [WMD=-16.97 mg/dL, p = 0.01], and homeostatic model assessment for insulin resistance (HOMA-IR) [WMD=-0.94, p = 0.005] significantly more than exercise only. However, probiotics plus exercise did not significantly change high-density lipoprotein (HDL) [WMD = 0.07 mg/dL, p = 0.9], fasting insulin [WMD=-1.47 µIU/mL, p = 0.4] or fasting blood glucose (FBG) [WMD=-1.57 mg/dL, p = 0.3] compared with exercise only. While not statistically significant, there were clinically relevant reductions in alanine aminotransferase (ALT) [WMD=-6.78 U/L, p = 0.1], triglycerides (TG) [WMD=-21.84 mg/dL, p = 0.1], and body weight (BW) [WMD=-1.45 kg, p = 0.5] for probiotics plus exercise compared with exercise only. The included studies exhibited significant heterogeneity for AST (I2 = 78.99%, p = 0.001), GGT (I2 = 73.87%, p = 0.004), LDL (I2 = 62.78%, p = 0.02), TC (I2 = 72.41%, p = 0.003), HOMA-IR (I2 = 93.86%, p = 0.001), HDL (I2 = 0.00%, p = 0.9), FBG (I2 = 66.30%, p = 0.01), ALT (I2 = 88.08%, p = 0.001), and TG (I2 = 85.46%, p = 0.001). There was no significant heterogeneity among the included studies for BW (I2 = 0.00%, p = 0.9).

CONCLUSION

Probiotic supplementation combined with exercise training elicited better results compared to exercise alone on liver enzymes, lipid profile, and insulin resistance in patients with NAFLD.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42023424290.

Effect of probiotics at different intervention time on glycemic control in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

Background

Type 2 diabetes mellitus(T2DM) is characterized by hyperglycemia. Gut microbiome adjustment plays a positive part in glucose regulation, which has become a hotspot. Probiotics have been studied for their potential to control the gut flora and to treat T2DM. However, the conclusion of its glucose-lowering effect is inconsistent based on different probiotic intervention times.

Objectives

To comprehensively evaluate how various probiotic intervention times affect glycemic control in people with T2DM.

Methods

We retrieved PubMed, Embase, Web of Science, and Cochrane Library on randomized controlled trials(RCTs)regarding the impact of probiotics on glycemic control in patients with T2DM from the inception to November 16, 2023. Separately, two researchers conducted a literature analysis, data extraction, and bias risk assessment of the involved studies. We followed the PRISMA guidelines, used RevMan 5.4 software for meta-analysis, and assessed the risk of bias by applying the Cochrane Handbook for Systematic Reviews 5.1.0.

Results

We included eight RCTs with 507 patients. Meta-analysis revealed that the use of probiotics might considerably reduce levels of glycosylated hemoglobin (HbA1c) {mean deviation (MD) = -0.33, 95% confidence interval (CI) (-0.59, -0.07), p = 0.01}, Insulin {standard mean deviation (SMD) = -0.48, 95% CI (-0.74, -0.22), p = 0.0003} and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR){SMD = -1.36, 95% CI (-2.30, -0.41), p = 0.005} than placebo group. No statistically significant differences were found regarding fasting blood glucose (FBG) and body mass index (BMI) {SMD = -0.39, 95% CI (-0.83, 0.05), p = 0.08}, {SMD = -0.40, 95% CI (-1.07, 0.27), p = 0.25}, respectively. Subgroup analyses, grouped by intervention times, showed that six to eight weeks of intervention improved HbA1c compared to the control group (p < 0.05), both six to eight weeks and 12-24 weeks had a better intervention effect on Insulin, and HOMA-IR (p < 0.05).In contrast, there was no statistically significant variation in the length between FBG and BMI regarding duration.

Conclusion

This meta-analysis found probiotics at different intervention times play a positive role in modulating glucose in T2DM, specifically for HbA1c in six to eight weeks, Insulin and HOMA-IR in six to eight weeks, and 12-24 weeks. To confirm our findings, further excellent large-sample research is still required.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023483325.

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.

Effect of zinc supplementation on glycemic biomarkers: an umbrella of interventional meta-analyses

BACKGROUND

Several studies have evaluated the effects of zinc supplementation on glycemic biomarkers in humans and have demonstrated varying results. We systematically evaluated the literature and performed an umbrella meta-analysis of the effects of zinc supplementation on type 2 diabetes biomarkers.

METHODS

A comprehensive literature search was conducted in the following databases; PubMed, Embase, Embase, Cochrane Library, Scopus, and Web of Science for studies published up to March 10, 2024.

RESULTS

Zinc supplementation was effective in reducing serum FBS (WMD: - 13.58, 95% CI: - 17.38, - 9.77; p < 0.001; SMD: - 0.52, 95% CI - 0.79, - 0.25; p =  < 0.001), insulin (SMD: - 0.67, 95% CI - 0.96, - 0.38; p < 0.001), HOMA-IR levels (WMD - 0.52, 95% CI - 0.66, - 0.38; p < 0.001; SMD: - 0.78, 95% CI - 1.02, - 0.42; p < 0.001), and HbA1c (WMD: - 0.35, 95% CI - 0.43, - 0.27; p < 0.001).

CONCLUSION

Zinc supplementation significantly reduced FBS, HOMA-IR, insulin and HbA1c. These findings suggest that zinc is potentially an effective complementary intervention to improve type 2 diabetes biomarkers.

Probiotics and synbiotics for glycemic control in diabetes: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

The escalating prevalence of diabetes mellitus may benefit from add-on therapeutic approaches. Given the recognized need for an updated synthesis of the literature, this systematic review and meta-analysis aimed to synthesize and critically assess the available randomized controlled trials (RCTs) that investigate the efficacy of probiotics and synbiotics on glycemic control in patients with Type 1 (T1DM) and Type 2 (T2DM) diabetes mellitus.

METHODS

Comprehensive searches were conducted on PubMed, Embase, CINAHL, Scopus, and Web of Science, focusing on adults with T1DM or T2DM. All comparators were deemed eligible. Primary outcomes included changes in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and insulin levels. Only RCTs were included, and the Cochrane RoB2 tool assessed the risk of bias. Random-effect models facilitated data analysis, supplemented by sensitivity, subgroup analyses, and meta-regressions.

RESULTS

A total of 537 records were screened, resulting in 41 RCTs for analysis, which comprises 2991 (54% females) patients with diabetes. The meta-analysis revealed statistically significant improvements in HbA1c (standardized mean difference (SMD) = -0.282, 95% CI: [-0.37, -0.19], p < 0.001), FPG (SMD = -0.175, 95% CI: [-0.26, -0.09], p < 0.001), and insulin levels (SMD = -0.273, 95% CI: [-0.35, -0.20], p < 0.001). A medium degree of heterogeneity between studies was found in HbA1c (I2 = 62.5%), FPG (I2 = 71.5%), and insulin levels (I2 = 66.4%) analyses. Subgroup analyses indicated that the efficacy varied based on the type of strains used and the country. Multispecies strains were particularly effective in improving HbA1c levels.

CONCLUSION

The study findings suggest that probiotics and synbiotics may be effective as complementary therapies for managing diabetes. Additionally, the study underscores the need for further tailored research that considers variables such as strain types and geographical factors to deepen the understanding of the role of these interventions in diabetes care.

REVIEW REGISTRATION NUMBER

PROSPERO (CRD42023396348).

Comparison of the efficacy of fish oil and probiotic supplementation on glucose and lipid metabolism in patients with type 2 diabetes: a systematic review and network meta-analysis

BACKGROUND

Abnormalities in glucose and lipid metabolism contribute to the progression and exacerbation of type 2 diabetes mellitus (T2DM). Fish oil and probiotics are dietary supplements that have the potential to improve glucose and lipid metabolism. However, their efficacy remains unclear in T2DM patients.

METHODS

PubMed, Embase, and the Cochrane Library were retrieved to collect randomized controlled trials (RCTs) on the efficacy of fish oil or probiotic supplementation in T2DM patients from the database inception to December 13, 2023. Primary outcome indicators encompassed glycated hemoglobin (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR) and blood lipid profile (triglyceride (TG) and total cholesterol (TC). Secondary outcome indicators included inflammatory markers such as tumor necrosis factor -α (TNF-α) and adipocytokine (including leptin and adiponectin). The R software was used for statistical analysis, and GraphPad Prism was used for figure rendering.

RESULTS

A total of 60 RCTs involving 3845 T2DM patients were included in the analysis. The results showed that the probiotics (Bifidobacterium, Lactobacillus, Lactococcus, Propionibacterium, etc.) were more effective in reducing HOMA-IR than fish oil (Surca = 0.935). Bifidobacterium demonstrated the highest efficacy in reducing HbA1c levels (Surca = 0.963). Regarding lipid metabolism, fish oil was superior to probiotics in lowering TG and TC levels (Surca values of 0.978 and 0.902, respectively). Furthermore, fish oil outperformed probiotics in reducing TNF-α (Surca = 0.839) and leptin (Surca = 0.712), and increasing adiponectin levels (Surca = 0.742). Node-splitting analysis showed good consistency (P > 0.05 for direct, indirect, and network comparison across various interventions).

CONCLUSIONS

In T2DM patients, fish oil was more effective than probiotics in regulating lipid metabolism. Probiotics outperformed fish oil in regulating glucose metabolism particularly; specifically, Bifidobacterium showed higher efficacy in reducing blood glucose.

The Effect of Probiotic Supplements on Metabolic Parameters of People with Type 2 Diabetes in Greece-A Randomized, Double-Blind, Placebo-Controlled Study

The role of probiotic supplementation in type 2 diabetes (T2D) treatment is controversial. The present study aimed to assess the effects of a multi-strain probiotic supplement (LactoLevureR (containing Lactobacillus acidophilus, Lactobacillus plantarum, Bifidobacterium lactis, and Saccharomyces boulardii)) over 6 months, primarily on glycemic control as well as on lipid levels and alterations in the gut microbiome, among individuals with T2D residing in Greece. A total of 91 adults with T2D (mean age [±SD] 65.12 ± 10.92 years, 62.6% males) were randomized to receive the probiotic supplement or a matching placebo capsule, once daily, for 6 months. Blood chemistries and anthropometric parameters were conducted every 3 months, and stool samples were collected at baseline and at 6 months. Significant reductions in HbA1c, fasting blood glucose, and total cholesterol were observed in participants treated with the probiotic supplement (n = 46) compared to the controls (n = 45), even after adjustment for a greater decrease in adiposity (waist circumference). Although there were no statistically significant differences in the diversity of the gut microbiome (α and β diversity), the administration of probiotics did influence several genera, metabolites, and key enzymes associated with diabetes. Overall, the administration of the multi-strain probiotic LactoLevureR over a 6-month period in individuals with T2D was well-tolerated and had a positive impact on metabolic parameters, alongside improvements in indices of adiposity.

Effect of probiotic supplementation on gastrointestinal motility, inflammation, motor, non-motor symptoms and mental health in Parkinson's disease: a meta-analysis of randomized controlled trials

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. Gut dysbiosis is hypothesized to cause PD; therefore, whether probiotics can be used as adjuvants in the treatment of PD is being actively investigated.

AIMS

We performed a systematic review and meta-analysis to evaluate the effectiveness of probiotic therapy in PD patients.

METHODS

PUBMED/MEDLINE, EMBASE, Cochrane, Scopus, PsycINFO and Web of Science databases were searched till February 20, 2023. The meta-analysis used a random effects model and the effect size was calculated as mean difference or standardized mean difference. We assessed the quality of the evidence using the Grade of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Eleven studies involving 840 participants were included in the final analysis. This meta-analysis showed high-quality evidence of improvement in Unified PD Rating Scale Part III motor scale (standardized mean difference [95% confidence interval]) (- 0.65 [- 1.11 to - 0.19]), non-motor symptom (- 0.81 [- 1.12 to - 0.51]), and depression scale (- 0.70 [- 0.93 to -0.46]). Moderate to low quality evidence of significant improvement was observed in gastrointestinal motility (0.83 [0.45-1.10]), quality of life (- 1.02 [- 1.66 to - 0.37]), anxiety scale (- 0.72 [- 1.10 to - 0.35]), serum inflammatory markers (- 5.98 [- 9.20 to - 2.75]), and diabetes risk (- 3.46 [- 4.72 to - 2.20]). However, there were no significant improvements in Bristol Stool Scale scores, constipation, antioxidant capacity, and risk of dyslipidemia. In a subgroup analysis, probiotic capsules improved gastrointestinal motility compared to fermented milk.

CONCLUSION

Probiotic supplements may be suitable for improving the motor and non-motor symptoms of PD and reducing depression. Further research is warranted to determine the mechanism of action of probiotics and to determine the optimal treatment protocol.

Nutritional supplements improve cardiovascular risk factors in overweight and obese patients: A Bayesian network meta-analysis

Background

Overweight and obesity are considered as one of the major risk factors for cardiovascular diseases (CVD). At present, many studies have proved that multiple nutritional supplements play an active role in metabolic diseases. However, the comparative efficacy of different nutritional supplements in improving indicators of cardiometabolic risk in obese and overweight patients is uncertain.

Methods

Cochrane Library, PubMed, Embase, and Web of Science were searched for the period from January 1990 to March 2022. A random-effect model was built in the Bayesian network meta-analysis. The surface under the cumulative ranking analysis (SUCRA) and clustering rank analysis was performed for ranking the effects.

Results

The study included 65 RCTs with 4,241 patients. In terms of glucose control, probiotic was more conductive to improve FBG (MD: -0.90; 95%CrI: -1.41 to -0.38), FINS (MD: -2.05; 95%CrI: -4.27 to -0.02), HOMA-IR (MD: -2.59; 95%CI -3.42 to -1.76). Probiotic (MD: -11.15, 95%CrI -22.16 to -1.26), omega-3 (MD: -9.45; 95%CrI: -20.69 to -0.93), VD (MD: -17.86; 95%CrI: -35.53 to -0.27), and probiotic +omega-3 (MD: 5.24; 95%CrI: 0.78 to 9.63) were beneficial to the improvement of TGs, TC and HDL-C, respectively. The SUCRA revealed that probiotic might be the best intervention to reduce FBG, FINS, HOMA-IR; Simultaneously, α-lipoic acid, VD, and probiotic + omega-3 might be the best intervention to improve TGs, TC, and HDL-C, respectively. Cluster-rank results revealed probiotic had the best comprehensive improvement effect on glucose metabolism, and probiotic + omega-3 may have a better comprehensive improvement effect on lipid metabolism (cluster-rank value for FBG and FINS: 3290.50 and for TGs and HDL-C: 2117.61).

Conclusion

Nutritional supplementation is effective on CVD risk factors in overweight and obese patients. Probiotic supplementation might be the best intervention for blood glucose control; VD, probiotic + omega-3 have a better impact on improving lipid metabolism. Further studies are required to verify the current findings.

Lactic Acid Bacteria: A Promising Tool for Menopausal Health Management in Women

Menopause is a period during which women undergo dramatic hormonal changes. These changes lead to physical and mental discomfort, are greatly afflictive, and critically affect women's lives. However, the current safe and effective management measures for women undergoing menopause are insufficient. Several probiotic functions of lactic acid bacteria (LAB) have been recognized, including alleviation of lactose intolerance, protection of digestive tract health, activation of the immune system, protection against infections, improvement of nutrient uptake, and improvement of the microbiota. In this review, we highlight the currently available knowledge of the potential protective effects of LAB on preventing or mitigating menopausal symptoms, particularly in terms of maintaining balance in the vaginal microbiota, reducing bone loss, and regulating the nervous system and lipid metabolism. Given the increasing number of women entering menopause and the emphasis on the management of menopausal symptoms, LAB are likely to soon become an indispensable part of clinical/daily care for menopausal women. Herein, we do not intend to provide a comprehensive analysis of each menopausal disorder or to specifically judge the reliability and safety of complementary therapies; rather, we aim to highlight the potential roles of LAB in individualized treatment strategies for the clinical management of menopause.