Effect of Chromium Supplementation on Serum Levels of Inflammatory Mediators: An Updated Systematic Review and Meta-analysis on Randomized Clinical Trials

Chromium has been recognized for its beneficial effects on inflammation reduction; therefore, we conducted a systematic review and meta-analysis to find the effect of chromium supplementation on serum levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) in subjects aged 18 years and older. Related articles were identified by searching databases such as the Cochrane Library, ClinicalTrials.gov, ISI Web of Science, Scopus, and PubMed up until Agust 2024. We computed the mean differences (MD) along with their standard deviations (SDs) to carry out the meta-analysis. Statistical heterogeneity of the intervention effects was assessed using I-squared statistics and Cochran's Q test. In total, twelve and eleven studies were included in the present systematic review and meta-analysis, respectively. The pooled results indicated that the differences in serum levels of CRP and TNF-alpha between chromium group and the comparison group were statistically significant (CRP: weighted mean difference (WMD) = -0.58 mg/L; 95% confidence interval (CI) = -0.95, -0.22 mg/L; P = 0.002; TNF-alpha: WMD = -1.22 pg/ml; 95% CI = -1.91, -0.53 pg/ml; p = 0.001). In contrast, chromium supplementation resulted in a non-significant decrease in serum levels of IL-6 (WMD = -0.63 pg/ml; 95% CI: -1.67, 0.4 pg/ml; P < 0.001). Our study supports the beneficial effect of chromium supplementation on serum concentration of CRP and TNF-alpha, but our results showed that chromium supplementation non-significantly reduced the serum levels of IL-6. However, it seems that chromium formulation, participants' BMI, sample size, and geographical region are strong variables that predict the effect of chromium supplementation on inflammatory mediators.