Abstract

CINNAMON USE IN TYPE 2 DIABETES: AN UPDATED META-ANALYSIS

Abdulrahman S. Alanazi*, M. U. Khan

ABSTRACT

Cinnamon has become a natural product of interest because it has been hypothesized to provide health benefits, such as the ability to lower serum lipids and blood glucose. There have been randomized controlled trials (RCTs) for its glycemic-lowering effects, but studies have been shown small conflicting results. We performed an updated meta-analysis of RCTs evaluating cinnamon’s effect on glycemia and lipid levels. Methods: Clinical trials were identified through MEDLINE, Cochrane, the Google scholar, MeSH, Medscape, www. Clinicaltrial.gov from 1990 to March 2015 were searched Included RCTs evaluated cinnamon compared with control in patients with type 2 diabetes and reported at least one of the following: glycated hemoglobin (A1c), fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), or triglycerides. Weighted mean differences (with 95% confidence intervals) for endpoints were calculated using random-effects models. Results: In a meta-analysis of 16 RCTs (n = 638 patients), cinnamon doses of 120 mg/d to 6 g/d for 4 to 18 weeks reduced levels of fasting plasma glucose,16 RCTs (n = 638 patients) (–0.38 gm/dL; 95% CI, –0.54 to –0.21 gm/dL), total cholesterol, 15 RCT (n=567), (–12.87 mg/ dL; 95% CI, –15.53 to -10.22 mg/dL), Cinnamon also increased levels of HDL-C, 10 RCTs (n=461 patients) (–0.14 mg/dL; 95% CI, –0.13 –0.15 mg/dL), and LDL-C, 15 RCTs (n=521 patients) (–9.07 mg/dL; 95% CI, –11.05 to –7.09 mg/dL), triglycerides, RCTs 15 (n=544 patients), (-13.25 mg/dL; 95% CI, -16.21 to -10.29 mg/dL). No significant effect on hemoglobin A1c levels, 11 RCTs (n=627), (0.07%; 95%, CI –0.03% to 0.16 %) was seen. High degrees of heterogeneity were present for all analyses. Conclusions: The consumption of cinnamon is associated with a statistically significant decrease in levels of fasting plasma glucose, total cholesterol, LDL-C, and triglyceride levels, and an increase in HDL-C levels; however, no significant effect on hemoglobin A1c was found. The high degree of heterogeneity may limit the ability to apply these results to patient care, because the preferred dose and duration of therapy are unclear.

Keywords: Cinnamon, glycemic-lowering effects, glycated hemoglobin (A1c).