The Effects of Synbiotic Supplementation on Glucose Metabolism and Lipid Profiles in Patients with Diabetes: a Systematic Review and Meta-Analysis of Randomized Controlled Trials

Although several studies have evaluated the effect of synbiotic intake on metabolic profiles in patients with diabetes, findings are inconsistent. This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the evidence on the effect of synbiotic intake on metabolic profiles in patients with diabetes. The PubMed, EMBASE, Web of Science, and Cochrane Library databases were systematically searched. All RCTs published up to 12 November 2016 were included. Two review authors independently assessed study eligibility, extracted data, and evaluated risk of bias of included studies. Heterogeneity was measured with a Q test and with I 2 statistics. Data were pooled by using the fix or random-effect model based on the heterogeneity test results and expressed as standardized mean difference (SMD) with 95% confidence interval (CI). A total of seven randomized controlled trials were included. Synbiotic consumption significantly changed glucose metabolism, including fasting plasma glucose (FPG) (SMD = -0.29; 95% CI, -0.47, -0.10), insulin concentrations (SMD = -0.84; 95% CI, -1.61, -0.06), homeostasis model assessment of insulin resistance (HOMA-IR) (SMD = -0.80; 95% CI, -1.58, -0.03), homeostatic model assessment-B cell function (HOMA-B) (SMD = -0.36; 95% CI, -0.71, -0.01), quantitative insulin sensitivity check index (QUICKI) (SMD = 0.46; 95% CI, 0.09, 0.82), and significantly improved lipid profiles, such as triglycerides (SMD = -0.36; 95% CI, -0.55, -0.17), very low density lipoprotein-cholesterol (SMD = -0.31; 95% CI, -0.55, -0.08), and total cholesterol (SMD = -0.32; 95% CI, -0.67, -0.03), but had no effect on low density lipoprotein-cholesterol (SMD = -0.07; 95% CI, -0.58, 0.43) and high density lipoprotein-cholesterol concentrations (SMD = -0.25; 95% CI, -0.81, 0.31). Synbiotic may result in an improvement in FPG, insulin, HOMA-IR, HOMA-B, QUICKI, triglycerides, and total cholesterol.