The effect of Saffron supplementation on waist circumference, HA1C, and glucose metabolism: A systematic review and meta-analysis of randomized clinical trials

Abstract Objective Carotenoids (including zeaxanthin and lycopene) and phytosterols reportedly confer beneficial effects on metabolic profile and function, which is of clinical importance. Thus, we sought to review the saffron effects on waist circumstance (WC), fasting plasma glucose (FPG), and HA1C concentrations reported in Randomized Control Trials (RCTs). Method A comprehensive systematic electronic search was performed in PubMed/MEDLINE, Embase, Google Scholar, Cochrane, Web of sciences, and SCOPUS to identify RCTs up to February 2019 without any language restrictions. The pooled weighted mean difference (WMD) calculated with DerSimonian-Laird random. PRISMA guidelines adhered to for this meta-analysis. Result Nine articles with 12 arms containing 595 participants were included in this study. Our study found WC was significantly reduced (WMD: −2.18 cm, 95 % CI: −4.05, −0.32) and FPG (WMD: −6.54 mg/dl, 95 % CI: −10.22, −2.85) following saffron intervention. Subgroup analysis highlighted that FPG levels (WMD: −10.24 mg/dl, 95 % CI: −15.76, −4.72) reduced significantly when intervention duration was longer than twelve weeks. There was no significant effect on HA1C levels (WMD: −0.13 mg/dl, 95 % CI: −0.31, 0.04) following saffron intervention. Conclusion In conclusion, the present study indicates beneficial effects on WC and FPG, following saffron supplementation.