The efficacy of propolis on markers of glycemic control in adults with type 2 diabetes mellitus: A systematic review and meta-analysis

Abstract

BACKGROUND AND OBJECTIVES: The impetus for the current study was to evaluate the efficacy of propolis supplementation on markers of glycemic status in adults with type 2 diabetes mellitus (T2DM). METHODS: A comprehensive search was conducted in PubMed, Scopus, Cochrane Library, Web of Science, and Google Scholar up to August 2018, identifying randomized controlled trials investigating the effect of propolis supplementation on glycemic markers in adults with T2DM. Cochrane Collaboration tool was used to evaluate the risk of bias assessment. A random-effects model was applied in the meta-analysis to compensate for potential heterogeneity among the included studies. RESULTS: Six randomized controlled trials comprising 373 participants were included in the systematic review and meta-analysis. The results of the meta-analysis revealed significant reductions in fasting plasma glucose (-13.51 mg/dl; 95 CI -24.98, -2.04) and hemoglobin A1C (-0.52%; 95% CI -0.94, -0.10) concentrations following propolis supplementation. However, no significant lowering effect was observed in fasting insulin levels (-0.53 pmol/L; 95% CI -1.69, 0.63) or homeostasis model assessment of insulin resistance (-0.543; 95% CI -1.72, 0.64). CONCLUSION: This systematic review and meta-analysis suggested that propolis supplementation may be effective in controlling glycemic levels for T2DM patients. Further studies are needed to confirm these results.