The effect of cumin (Cuminum cyminum L.) supplementation on glycemic indices: A systematic review and meta-analysis of randomized controlled trials.

We aimed to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the effect of cumin supplementation on markers of glycemic control in adults. A comprehensive literature search was conducted up from inception to November 2020 on PubMed, Scopus, Web of Sciences, and Cochrane electronic databases. Studies that compared the effect of cumin with placebo on fasting blood sugar (FBS), serum insulin, and homeostasis model assessment-estimated insulin resistance (HOMA-IR) index in adults were considered eligible. Weighted mean difference (WMD) (with 95% confidence intervals) for endpoints were calculated using the random-effects model. Finally, a total of eight RCT studies involving 552 participants were included in the review. The results of the meta-analysis suggest that cumin supplementation did not significantly alter serum FBS (WMD: -17.77 mg/dl; 95% CI: -36.42 to 0.87, p = .06), insulin (WMD: -0.49 Hedges' g; 95% CI: -1.19 to 0.21, p =.16) levels and HOMA-IR (WMD: -0.06; 95% CI: -0.21 to 0.10, p = 0.48) index. These results do not support the use of cumin supplementation for improving glycemic markers in adults. However, further high-quality trials are still needed to confirm these results.