Effects of probiotic supplementation on anthropometric and metabolic characteristics in adults with metabolic syndrome: A systematic review and meta-analysis of randomized clinical trials

Aims: We conducted a systematic review and meta-analysis to evaluate evidence from randomized controlled trials (RCTs) documenting the effectiveness of supplementation with pro-/synbiotics versus placebo controls on anthropometric and metabolic (glucoregulatory status, lipid profile) indices in adults with metabolic syndrome (MetS). Methods: Databases of MEDLINE, Scopus, Embase, Web of Science, and Cochrane Library were searched through March 2020 to identify eligible RCTs evaluating the effects of pro-/synbiotic consumption in adults (≥18 years) with MetS. Mean differences (MDs) and 95% confidence intervals (CIs) were pooled using random-effects models. Results: Ten eligible publications (9 RCTs, n = 344 participants) were included. Supplementation with pro-/synbiotics reduced total cholesterol (TC) in adults with MetS versus placebo (MD: −6.66 mg/dL, 95% CI: −13.25 to −0.07, P = 0.04, I2 = 28.8%, n = 7), without affecting weight, body mass index, waist circumference, fasting blood sugar, homeostasis model assessment for insulin resistance, insulin, triglyceride, low-density lipoprotein cholesterol, or high-density lipoprotein cholesterol (P > 0.05). Conclusions: Pro-/synbiotic consumption may be beneficial in reducing TC levels in adults with MetS. However, our observations do not support the effectiveness of pro-/synbiotics consumption on other anthropometric or metabolic outcomes of MetS. Further investigations with larger sample sizes are required to confirm these findings.