Effects of oral supplementation with probiotics or synbiotics in overweight and obese adults: a systematic review and meta-analyses of randomized trials.

CONTEXT: Recent evidence suggests that modulation of the gut microbiota may contribute to body weight control. OBJECTIVE: This systematic review aimed to assess the effects of oral supplementation with probiotics or synbiotics on body weight, body mass index (BMI), and waist circumference in overweight and obese adults (BMI ≥ 25 kg/m2). DATA SOURCES: Five electronic databases-PubMed, Embase, Cochrane Library/CENTRAL, LILACS, and Web of Science-were searched from inception to August 2017. No language restrictions were applied. STUDY SELECTION: Randomized and quasi-randomized parallel trials that assessed the effects of oral supplementation with probiotics or synbiotics vs any other intervention but bariatric surgery or fecal transplantation in overweight or obese adults were selected. DATA EXTRACTION: Three teams of 2 authors independently assessed risk of bias and extracted data from the included trials. Data were pooled using inverse-variance random-effects meta-analyses. The quality of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. RESULTS: Nineteen randomized trials (28 publications, 1412 participants) were included. There were no differences in mean body weight change [mean difference (MD), -0.54 kg; 95%CI, -1.09 to 0.01; I2 = 0%; moderate quality of evidence) or mean BMI change (MD, -0.19 kg/m2; 95%CI, -0.43 to 0.04; I2 = 51%; low quality of evidence) between groups who received probiotics or synbiotics and control groups. Oral supplementation with probiotics or synbiotics reduced mean waist circumference compared with control (MD, -0.82 cm; 95%CI, -1.43 to -0.21; I2 = 46%; low quality of evidence). CONCLUSIONS: The findings suggest that oral supplementation with probiotics or synbiotics has a small effect to reduce waist circumference but no effect on body weight or BMI, although the quality of evidence is low to moderate. Therefore, the current evidence is not definitive. Large-scale trials are needed and may help to better inform clinical practice. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42018075126.

Effects of inulin-type fructans, galacto-oligosaccharides and related synbiotics on inflammatory markers in adult patients with overweight or obesity: A systematic review.

BACKGROUND & AIMS: Studies in humans with overweight or obesity have reported that some prebiotics and synbiotics have beneficial effects on metabolic endotoxaemia and immune function. However, to date, no systematic review of controlled clinical trials assessed this topic. The aim of this study was to evaluate the effects of inulin-type fructans, galacto-oligosaccharides and related synbiotics on inflammatory markers in adults with overweight or obesity. METHODS: A systematic review of the literature was performed until November 6, 2015 in four electronic databases and reference lists of all included articles and relevant reviews in the field, without using any filter. RESULTS: Ten trials (six prebiotic and four synbiotic trials) representing 534 overweight/obese adults were included. All trials evaluated C-reactive protein or high-sensitivity C-reactive protein, four trials evaluated cytokines (two prebiotic and two synbiotic trials) and five trials evaluated endotoxin (four prebiotic and one synbiotic trials). Six trials (two with galacto-oligosaccharide, one with inulin and three with different synbiotics) showed a reduction on high-sensitivity C-reactive protein. Four trials (one with oligofructose-enriched inulin, one with inulin and two with different synbiotics) showed a reduction on interleukin-6 and/or tumor necrosis factor. Four trials (one with galacto-oligosaccharide, one with oligofructose-enriched inulin, one with inulin and one with synbiotic) showed a reduction on endotoxin. CONCLUSIONS: Some prebiotics and synbiotics may have immunomodulatory action, however, more randomized controlled trials are needed to support the clinical use of inulin-type fructans, galacto-oligosaccharides or related synbiotics for the treatment of metabolic endotoxaemia or low-grade inflammation in overweight/obese people.

Effects of Prebiotic and Synbiotic Supplementation on Inflammatory Markers and Anthropometric Indices After Roux-en-Y Gastric Bypass: A Randomized, Triple-blind, Placebo-controlled Pilot Study.

BACKGROUND: Studies have shown that prebiotics and synbiotics modulate the intestinal microbiota and may have beneficial effects on the immune response and anthropometric indices; however, the impact of the use of these supplements after bariatric surgery is not yet known. GOALS: This study investigated the effects of prebiotic and synbiotic supplementation on inflammatory markers and anthropometric indices in individuals undergoing open Roux-en-Y gastric bypass (RYGB). STUDY: In this randomized, controlled, and triple-blind trial conducted as a pilot study, individuals undergoing RYGB (n=9) and healthy individuals (n=9) were supplemented with 6 g/d of placebo (maltodextrin), prebiotic (fructo-oligosaccharide, FOS), or synbiotic (FOS+Lactobacillus and Bifidobacteria strains) for 15 days. RESULTS: Interleukin-1ß, interleukin-6, tumor necrosis factor-α, C-reactive protein, albumin, and the C-reactive protein/albumin ratio showed no significant changes on comparison between groups after supplementation. The reduction in the body weight of patients undergoing RYGB was 53.8% higher in the prebiotic group compared with the placebo group (-0.7 kg, P=0.001), whereas the reduction in the BMI and the increase in the percentage of excess weight loss were higher in the placebo and the prebiotic groups compared with the synbiotic group (P<0.05). CONCLUSIONS: Supplementation of FOS increased weight loss, whereas both prebiotics and synbiotics were not able to promote significant changes in inflammatory markers, although in most analyses, there was a reduction in their absolute values. The use of FOS may represent a potential adjunct in the treatment of obesity.

A systematic review and meta-analysis of the prebiotics and synbiotics effects on glycaemia, insulin concentrations and lipid parameters in adult patients with overweight or obesity.

BACKGROUND & AIMS: Several studies have reported the effects of prebiotics and synbiotics supplementation in lipid profile and glucose homeostasis, however a pooled analysis of clinical trials that assessed these parameters has not been performed in overweight or obese individuals. The aim of this study was to evaluate the effects of prebiotics and synbiotics on plasma lipid profile, fasting insulin and fasting glucose in adults with overweight or obesity. METHODS: Randomized controlled trials were systematically searched before May 2014 in electronic databases and screening reference lists. Combined and stratified (diabetics and non-diabetics trials) meta-analyzes were performed. RESULTS: Thirteen trials, representing 513 adult participants with Body Mass Index ≥25 kg/m² were included. Prebiotic supplementation reduced plasma total cholesterol (SMD -0.25; 95% CI -0.48, -0.02) and LDL-c (SMD -0.22; 95% CI -0.44, -0.00) concentrations in overall analysis, and reduced triglycerides (SMD -0.72; 95% CI -1.20, -0.23) and increased HDL-c (SMD 0.49; 95% CI 0.01, 0.97) concentrations in diabetic trials. Synbiotic supplementation reduced plasma fasting insulin (SMD -0.39; 95% CI -0.75, -0.02) and triglycerides (SMD -0.43; 95% CI -0.70, -0.15) concentrations. CONCLUSIONS: The improvement of the evaluated parameters supports prebiotics and synbiotics supplementation as an adjuvant therapy in obesity-related comorbidities, such as dyslipidemia and insulin resistance.