Effect of cinnamon (Cinnamomum Zeylanicum) supplementation on serum C-reactive protein concentrations: A meta-analysis and systematic review

Complement Ther Med. 2019 Feb:42:271-278. doi: 10.1016/j.ctim.2018.12.005. Epub 2018 Dec 7.


Objective: The effect of cinnamon (Cinnamomum Zeylanicum) on serum C-reactive protein (CRP), an acute phase protein commonly used as a marker of inflammation, is uncertain. Therefore, the objective of the present study was to conduct a systematic review and meta-analysis of published randomised controlled trials (RCTs) of cinnamon to determine the effect on levels of serum CRP, relative to controls.

Design: Studies were identified by a search of electronic databases including PubMed, Cochrane Library, Google Scholar and Scopus before August 2018. Combined and stratified analyses were used. Weighted mean differences (WMD) and its 95% confidence interval were estimated for net change in serum CRP by using random-effects model. The heterogeneity of meta-analysis was assessed by χ2 and I2 test.

Results: Six studies were identified, and data from 285 participants were included. Pooled analysis showed significant reductions in serum CRP (WMD: -0.81 mg/L, 95% CI: -1.36 to -0.26, p = 0.004), with significant heterogeneity between selected studies. Improvements in sub-group analysis were observed when baseline CRP levels were greater than 3 mg/dL, and in trials of >12 weeks duration. Doses <1500 mg/day and ≥1500 mg/day were effective in lowering serum CRP (WMD: -0.56 mg/dL, 95% CI: -1.01 to -0.10, p = 0.02 and WMD: -2.13 mg/dL, 95% CI: -4.08 to -0.19, p = 0.03), respectively, with significantly reduced heterogeneity in trials with lower doses of cinnamon <1500 mg/day (test for heterogeneity: P = 0.22 and I2 = 33%). No changes were found in controls.

Conclusion: Cinnamon supplementation improves levels of serum CRP, particularly in chronic conditions, where basal CRP levels are raised. Further well-designed studies are warranted to confirm or not the above-mentioned findings.

Keywords: Anti-inflammatory; CRP; Cinnamon; Meta-analysis; RCT.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Animals
  • C-Reactive Protein / metabolism*
  • Cinnamomum zeylanicum / chemistry*
  • Dietary Supplements
  • Humans
  • Inflammation / blood
  • Inflammation / drug therapy
  • Nutrition Therapy / methods
  • Plant Preparations / pharmacology*
  • Plant Preparations / therapeutic use*
  • Randomized Controlled Trials as Topic


  • Plant Preparations
  • C-Reactive Protein