The effect of Royal jelly on liver enzymes and glycemic indices: A systematic review and meta-analysis of randomized clinical trials

Background: Royal jelly (RJ) may contribute to glycemic control and liver function through various mechanisms. The present study aimed to quantify the effect of RJ supplementation on these outcomes.Methods: A literature search of Web of Science, Scopus, and PubMed/Medline, was conducted for RCTs investigating the efficacy of RJ on plasma liver enzymes and glycemic indices. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes using a random-effects model.Results: Ten RCTs were selected for inclusion in this meta-analysis. Combined estimate of effect sizes for the impact of RJ on neither the plasma liver enzymes nor the glycemic indices were statistically significant. Subgroup analysis showed a significant reduction of serum FPG in trials with intervention duration & GE; 8 weeks (WMD:-4.28 mg/dl, 95% CI-7.41 to-1.14 mg/dl, p = 0.007), and those conducted in non-healthy populations (WMD:-4.28 mg/dl, 95% CI-7.41 to-1.14, p = 0.007).Conclusion: RJ does not significantly affect liver function and glycemic profile of adult population. In trials with longer intervention and those conducted in non-healthy populations a significant reduction of serum FBG was observed. This meta-analysis should be repeated in the future, with more primary articles included, in order to provide conclusive results.