BACKGROUND: It has been unclear whether supplemental probiotics therapy improves clinical outcomes in type 2 diabetic patients. This meta-analysis aimed to summarize the effect of probiotics on glucose and lipid metabolism and C-reactive protein (CRP) from 12 randomized controlled trials (RCTs).

MATERIAL AND METHODS: An up-to-date search was performed for all relevant RCTs up to April 2016 from PubMed, Embase, and Cochrane Library. Standardized mean difference (SMD) and weighted mean difference (WMD) were calculated for a fixed-effect and random-effect meta-analysis to assess the impact of supplemental probiotics on fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile, and CRP level.

RESULTS: A total of 12 studies (684 patients) were entered into the final analysis. The effect of probiotics was significant on reducing HbA1c level (standardized mean difference [SMD], –0.38; confidence interval [CI], –0.62 to –0.14, P=0.002; I²=0%, P=0.72 for heterogeneity), fasting insulin level (SMD, –0.38; CI –0.59 to –0.18, P=0.0003; I²=0%, P=0.81 for heterogeneity), and HOMA-IR (SMD, –0.99; CI –1.52 to –0.47, P=0.0002; I²=86%, P<0.00001 for heterogeneity). Pooled results on effects of probiotics on FPG, CRP, or lipid profile were either non-significant or highly heterogeneous.

CONCLUSIONS: This meta-analysis demonstrated that probiotics supplementation was associated with significant improvement in HbA1c and fasting insulin in type 2 diabetes patients. More randomized placebo-controlled trials with large sample sizes are warranted to confirm our conclusions.

Keywords: Diabetes Mellitus, Type 2, Probiotics