The effects of Royal Jelly consumption on lipid profile: A GRADE-assessed systematic review and dose-response meta-analysis

Background: Inconsistent evidence exists regarding the impact of Royal Jelly (RJ) on cardio-metabolic risk fac-tors. Hence, this meta-analysis aimed to identify this effect.Method: Database search through PubMed/Medline, Web of Science, and SCOPUS was performed until April 2023 to identify eligible trials. Estimated 95% confidence (CI) and the weighted mean difference (WMD) was used for triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL) through the random-effects model. Results: RJ could significantly reduce TC (WMD:-8.75; 95%CI:-15.50,-1.99; P = 0.01; I2 = 68.5%; P hetero-geneity= 0.21). The protective effect of RJ against serum TC was stronger in unhealthy participants, > 8 weeks of supplement administration, > 3000 mg/d of RJ, and in both sexes. Neither the all-study combination nor the subgroup analysis showed a significant effect of this supplementation on TG, LDL and HDL. Dose-response analysis showed a greater reduction in HDL and a greater elevation in TG, following higher doses of RJ sup-plementation. Longer duration of intervention also led to lower LDL levels. In terms of the certainty of the ev-idence, TG, TC and HDL were regarded as moderate and LDL as low quality.Conclusions: RJ can reduce the risk of cardiovascular diseases by reducing the level of TC, and long-term sup-plementation could improve the level of HDL and LDL.