Do probiotics, prebiotics and synbiotics affect adiponectin and leptin in adults? A systematic review and meta-analysis of clinical trials.

Human studies have reported controversial findings regarding the health promoting effects of probiotic, prebiotic and synbiotic on adiponectin and leptin levels. This systematic review and meta-analysis was conducted to understand the effect of probiotics, prebiotics or synbiotics on adiponectin and leptin levels in adults. Electronic searches were performed in PubMed, Scopus, Web of Science, Cochrane Library and Google scholar up to February 11, 2018 without any restriction. Controlled clinical trials, in any age of adults, which reported the effect of probiotic, prebiotic and synbiotic on serum level of adiponectin and leptin were included. As leptin and adiponectin were reported in different units across the studies, Hedges's adjusted g was used to calculate effect size. A random-effects model was used to pool calculated effect sizes. Of 12 eligible studies, 10 publications focused on probiotics, and only 3 studies reported the effect of prebiotics (n = 2) or synbiotics (n = 1) on leptin and adiponectin. There were no significant changes in adiponectin (Hedges' g = -0.04; 95% CI: -0.27, 0.19) and leptin (Hedges' g = -0.30; 95% CI: -0.86, 0.26) in probiotic group compared with controls. Subgroup analyses ranged in heterogeneity from 0% to 93%, but no subgroup showed an effect of probiotics on adiponectin or leptin. There were limited studies regarding the effect of prebiotic and synbiotic on adiponectin and leptin. Although previous studies reported several health promoting effects of probiotics, we could not find any pooled effect on adiponectin and leptin.

Rouhani MH ，Hadi A ，Ghaedi E ，Salehi M ，Mahdavi A ，Mohammadi H ... -  《-》

The effect of probiotic and synbiotic supplementation on appetite-regulating hormones and desire to eat: A systematic review and meta-analysis of clinical trials.

Recent studies have demonstrated the effect of probiotics, prebiotics, and synbiotics on adiponectin and leptin levels; however, those findings remain contested. The present study aimed to explore the impact of probiotics/synbiotics on appetite-regulating hormones and the desire to eat. A systematic review was conducted by searching the Medline (PubMed) and Scopus databases from inception to December 2021, using relevant keywords and MeSH terms, and appropriate randomized controlled trials (RCTs) were extracted. The standardized mean differences (SMD) and 95% confidence intervals (95%CIs) were calculated as part of the meta-analysis using a random-effect model to determine the mean effect sizes. Analysis of Galbraith plots and the Cochrane Chi-squared test were conducted to examine heterogeneity. Meta-analysis of data from a total of 26 RCTs (n = 1536) showed a significant decrease in serum/plasma leptin concentration following probiotic/synbiotic supplementation (SMD: -0.38, 95%CI= -0.638, -0.124); P-value= 0.004; I2= 69.4%; P heterogeneity < 0.001). The leptin level decrease from probiotic/synbiotic supplementation was higher in patients with NAFLD than those with overweight/obesity or type 2 diabetes mellitus/ metabolic syndrome/ prediabetes. Probiotic/synbiotic supplementation was associated with a trending increase in adiponectin levels, stronger in patients with type 2 diabetes mellitus, metabolic syndrome, and prediabetes (SMD: 0.25, 95%CI= 0.04, 0.46) µg/mL; P-value= 0.021; I2 = 16.8%; P heterogeneity= 0.30). Additionally, supplementation with probiotic/synbiotic was linked to a slight increase in desire to eat (SMD: 0.34, 95%CI= 0.03, 0.66) P-value = 0.030; I2 = 39.4%; P heterogeneity= 0.16). Our meta-analysis indicates a favorable impact of probiotic/synbiotic supplementation on regulating leptin and adiponectin secretion.

Noormohammadi M ，Ghorbani Z ，Löber U ，Mahdavi-Roshan M ，Bartolomaeus TUP ，Kazemi A ，Shoaibinobarian N ，Forslund SK ... -  《-》

Orally Ingested Probiotics, Prebiotics, and Synbiotics as Countermeasures for Respiratory Tract Infections in Nonelderly Adults: A Systematic Review and Meta-Analysis.

The impact of gut microbiota-targeted interventions on the incidence, duration, and severity of respiratory tract infections (RTIs) in nonelderly adults, and factors moderating any such effects, are unclear. This systematic review and meta-analysis aimed to determine the effects of orally ingested probiotics, prebiotics, and synbiotics compared with placebo on RTI incidence, duration, and severity in nonelderly adults, and to identify potential sources of heterogeneity. Studies were identified by searching CENTRAL, PubMed, Scopus, and Web of Science up to December 2021. English-language, peer-reviewed publications of randomized, placebo-controlled studies that tested an orally ingested probiotic, prebiotic, or synbiotic intervention of any dose for ≥1 wk in adults aged 18-65 y were included. Results were synthesized using intention-to-treat and per-protocol random-effects meta-analysis. Heterogeneity was explored by subgroup meta-analysis and meta-regression. Risk of bias was assessed using the Cochrane risk-of-bias assessment tool for randomized trials version 2 (RoB2). Forty-two manuscripts reporting effects of probiotics (n = 38), prebiotics (n = 2), synbiotics (n = 1) or multiple -biotic types (n = 1) were identified (n = 9179 subjects). Probiotics reduced the risk of experiencing ≥1 RTI (relative risk = 0.91; 95% CI: 0.84, 0.98; P = 0.01), and total days (rate ratio = 0.77; 95% CI: 0.71, 0.83; P < 0.001), duration (Hedges' g = -0.23; 95% CI: -0.39, -0.08; P = 0.004), and severity (Hedges' g = -0.16; 95% CI: -0.29, -0.03; P = 0.02) of RTIs. Effects were relatively consistent across different strain combinations, doses, and durations, although reductions in RTI duration were larger with fermented dairy as the delivery matrix, and beneficial effects of probiotics were not observed in physically active populations. Overall risk of bias was rated as "some  concerns" for most studies. In conclusion, orally ingested probiotics, relative to placebo, modestly reduce the incidence, duration, and severity of RTIs in nonelderly adults. Physical activity and delivery matrix may moderate some of these effects. Whether prebiotic and synbiotic interventions confer similar protection remains unclear due to few relevant studies. This trial was registered at https://www.crd.york.ac.uk/prospero/ as CRD42020220213.

Coleman JL ，Hatch-McChesney A ，Small SD ，Allen JT ，Sullo E ，Agans RT ，Fagnant HS ，Bukhari AS ，Karl JP ... -  《-》

Orally Ingested Probiotic, Prebiotic, and Synbiotic Interventions as Countermeasures for Gastrointestinal Tract Infections in Nonelderly Adults: A Systematic Review and Meta-Analysis.

Meta-analyses have not examined the prophylactic use of orally ingested probiotics, prebiotics, and synbiotics for preventing gastrointestinal tract infections (GTIs) of various etiologies in adult populations, despite evidence that these gut microbiota-targeted interventions can be effective in treating certain GTIs. This systematic review and meta-analysis aimed to estimate the effects of prophylactic use of orally ingested probiotics, prebiotics, and synbiotics on GTI incidence, duration, and severity in nonelderly, nonhospitalized adults. CENTRAL, PubMed, Scopus, and Web of Science were searched through January 2022. English-language, peer-reviewed publications of randomized, placebo-controlled studies testing an orally ingested probiotic, prebiotic, or synbiotic intervention of any dose for ≥1 wk in adults who were not hospitalized, immunosuppressed, or taking antibiotics were included. Results were analyzed using random-effects meta-analyses of intention-to-treat (ITT) and complete case (CC) cohorts. Heterogeneity was explored by subgroup meta-analysis and meta-regression. The risk of bias was assessed using the Cochrane risk-of-bias 2 tool. Seventeen publications reporting 20 studies of probiotics (n = 16), prebiotics (n = 3), and synbiotics (n = 1) were identified (n > 6994 subjects). In CC and ITT analyses, risk of experiencing ≥1 GTI was reduced with probiotics (CC analysis-risk ratio: 0.86; 95% CI: 0.73, 1.01) and prebiotics (risk ratio: 0.80; 95% CI: 0.66, 0.98). No effects on GTI duration or severity were observed. Sources of heterogeneity included the study population and number of probiotic strains administered but were often unexplained, and a high risk of bias was observed for most studies. The specific effects of individual probiotic strains and prebiotic types could not be assessed owing to a lack of confirmatory studies. Findings indicated that both orally ingested probiotics and prebiotics, relative to placebo, demonstrated modest benefit for reducing GTI risk in nonelderly adults. However, results should be interpreted cautiously owing to the low number of studies, high risk of bias, and unexplained heterogeneity that may include probiotic strain-specific or prebiotic-specific effects. This review was registered at PROSPERO as CRD42020200670.

Fagnant HS ，Isidean SD ，Wilson L ，Bukhari AS ，Allen JT ，Agans RT ，Lee DM ，Hatch-McChesney A ，Whitney CC ，Sullo E ，Porter CK ，Karl JP ... -  《-》

Probiotics, prebiotics, and synbiotics for the improvement of metabolic profiles in patients with chronic kidney disease: A systematic review and meta-analysis of randomized controlled trials.

Zheng HJ ，Guo J ，Wang Q ，Wang L ，Wang Y ，Zhang F ，Huang WJ ，Zhang W ，Liu WJ ，Wang Y ... -  《-》