The effect of cinnamon supplementation on lipid profiles in patients with type 2 diabetes: A systematic review and meta-analysis of clinical trials

Objective: The present systematic review and meta-analysis was performed to evaluate the effect of cinnamon supplementation on blood lipid profiles in patients with type 2 diabetes. Methods: A systematic search (with no language restrictions) was performed in PubMed, Embase, Scopus, Web of Science, and Cochrane Library to identify relevant clinical trials up to 8th March 2020. Weighted mean differences (WMDs) and 95 % confidence intervals (CI) were pooled based on the random-effects model. Heterogeneity, publication bias, and sensitivity analyses were performed based on standard methods. Results: Sixteen studies, involving 1025 participants, were included in the meta-analysis. This study found a significant decrease in triglycerides (TG) (WMD: -26.27 mg/dl, 95 % CI: [-38.93, -13.61], P < 0.001), total cholesterol (TC) (WMD: -13.93 mg/dl, 95 % CI: [-25.64, -2.22], P = 0.020), and low-density lipoprotein cholesterol (LDL-C) levels (WMD: -6.13 mg/dl, 95 % CI: [-10.72, -1.53], P = 0.009), while no change was observed on high-density lipoprotein cholesterol (HDL) concentration (WMD: 0.64 mg/dl, 95 % CI: [-0.18, 1.46], P = 0.128), in patients with type 2 diabetes. The reduction in TG, TC, and LDL-C was greater in; Eastern compared to Western countries, and studies with a duration of < 2 compared to >= 2 months. The increase in HDL was greater in; participants with a BMI >= 30 compared to <30, Western compared to Eastern countries, and intervention durations of >= 2 compared to < 2 months. Conclusions: Cinnamon supplementation significantly decreased serum TG, TC, and LDL-C concentrations, but did not change HDL-C levels, in patients with type 2 diabetes.