Effects of cinnamon on controlling metabolic parameters of polycystic ovary syndrome: A systematic review and meta-analysis.

Cinnamon as a traditional medicine has been widely used in various disorders such as headache, toothache, common cold, diarrhea, flatulence, fever, amenorrhea frigidity. However, the effect of cinnamon supplementation on metabolic parameters of polycystic ovary syndrome (PCOS) patients has not been fully assessed.Clinical trials have shown contradictory effects of cinnamon supplementation on metabolic parameters of polycystic PCOS patients. Therefore, we evaluated the effect of cinnamon supplementation on metabolic parameters of PCOS patients through a systematic review and meta-analysis of clinical trials.PubMed, Embase, the Cochrane library, Scopus and Web of Science databases (until August 2019) were searched to identify potential clinical trials with information on cinnamon supplementation on metabolic parameters among PCOS patients. Weighted Mean Differences was pooled using a random-effects model. Standard methods were used for assessment of heterogeneity, publication bias and sensitivity analysis.Pooling five clinical trials (five treatment arms) together did not show any significant effect on body weight (WMD: -0.74 kg, 95% CI: -3.17 to 1.69) and body mass index (BMI) (WMD: -1.47, 95% CI: -4.07 to 1.12). Our results illustrated that a significant decrease of fasting blood sugar (WMD: -5.32, mg/dL95% CI: -10.46 to -0.17), fasting insulin (WMD: -4.10, μIU/dL95% CI: -6.76 to -0.144) and HOMA-IR (WMD: -0.69 95% CI: -1.37 to -0.004) were observed after cinnamon treatment. Moreover, our findings demonstrated that oral cinnamon supplementation in PCOS patients led to significant reduction of serum level of LDL-C, total cholesterol, and triacylglycerol. Besides, an improvement of serum concentration of HDL-C was shown by cinnamon supplementation.Generally, present study indicated that cinnamon supplementation may help PCOS patients to manage their metabolic parameters. Future prospective randomized clinical trials with longer intervention duration are warranted to obtain a precise conclusion.