Krittanawong C, Isath A, Scott CZ, Wang Z, Kaplin S, Jneid H, Lavie CJ, Virani SS
BACKGROUND: Cinnamon has been used as a traditional herbal medication for decades. Several studies have investigated cinnamon consumption and cardiovascular risk. So far, the evidence remains inconclusive. Thus, we aim to systematically review the currently available literature and quantify the evidence, if possible.METHODS: We systematically searched Ovid MEDLINE, Ovid Embase, Ovid Cochrane Database of Systematic Reviews, Scopus, and Web of Science from database inception in 1966 through December 2020. The exposure of interest was cinnamon consumption, the outcome was cardiovascular risk defined as hemoglobin A1C, low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c). Two investigators independently reviewed the data. Conflicts were resolved through consensus. Random-effects meta-analyses were used.RESULTS: Of 23 studies (1070 subjects), the included studies were heterogeneous, generally of very poor quality. We found no difference in LDL-c levels in patients who consumed cinnamon vs those who did not, with a weighted mean difference (WMD) of 0.38 (confidence interval [CI], -6.07-6.83). We also found no difference in HDL-c between the 2 groups with WMD 0.40 (CI, -1.14-1.94). In addition, we found no statistical differences in hemoglobin A1C between the 2 groups with WMD of 0.0 (CI, -0.44-0.45).CONCLUSIONS: Our meta-analysis suggests that there is no association between cinnamon consumption and differences in LDL-c, HDL-c, and hemoglobin A1C levels. Further randomized control trials studies using a robust design with long-term cinnamon consumption are needed to further investigate any potential effect. (C) 2021 Elsevier Inc. All rights reserved.