A Meta-analysis of Randomized Controlled Trials of the Effect of Probiotic Food or Supplement on Glycemic Response and Body Mass Index in Patients with Type 2 Diabetes, Updating the Evidence

Background: To investigate the effects of probiotics on glucose metabolism and body mass index (BMI), and compare the efficacy of probiotic food with the probiotic supplement in patients with type 2 diabetes mellitus using a meta-analysis of randomized, controlled trials. Methods: Online databases Embase, Web of Science, and PubMed were searched until November 2019 to identify eligible articles. Fourteen trials were included. Results: Probiotic consumption reduced fasting plasma glucose (FPG) (SMD=-0.38, 95% CI: -0.76 to 0.01), glycosylated hemoglobin (HbA1c) (SMD=-0.64, 95% CI: -0.91 to -0.38), fasting insulin concentration (SMD=-0.48, 95% CI, -0.81 to -0.15), HOMA-IR (SMD=-1.01, 95% CI, -1.51 to -0.52), and BMI (SMD=-0.02, 95%CI, -0.17 to 0.13) in intervention groups compared with control groups. Subgroup analysis was conducted to trials with probiotic foods and probiotic supplements. Both of probiotic foods (SMD: -0.65, 95% CI: -1.04 to -0.26; SMD: -1.17, 95% CI: -2.14 to -0.20, respectively) and supplements (SMD: -0.64, 95% CI: -1.01 to -0.27; SMD: -0.98, 95% CI: -1.55 to -0.40, respectively) made significant reduction in HbA1c and HOMA.IR. Meta-analysis of trials with probiotic foods found non-significant changes in FBG and fasting insulin concentration (SMD: 0.11, 95% CI: -0.52 to 0.75; SMD: -0.14, 95% CI: -0.48 to 0.20, respectively); however the changes in trials with probiotic supplements were significant (SMD: -0.73, 95% CI: -1.22 to -0.23; SMD: -0.57, 95% CI: -0.97 to -0.17, respectively). Probiotic foods cause a non-significant raise in BMI (SMD: 0.23, 95% CI: -0.03 to 0.49); however, meta-analysis of trials with probiotic supplements found a non-significant reduction in BMI (SMD: -0.13, 95% CI: -0.31 to 0.04). Conclusion: The present meta-analysis suggests that consuming probiotics could improve glucose metabolism and affect body weight, with a potentially greater effect when probiotics are used as supplements.