Effect of curcumin on proinflammatory cytokines: A meta-analysis of randomized controlled trials.
Level 1 - systematic review of randomized trials
Meta-analysis of randomized controlled trials
PubMed 33934954 · doi:10.1016/j.cyto.2021.155541
What was done
A systematic review and meta-analysis of literature up to March 2021 evaluated the effect of curcumin or turmeric supplementation versus placebo on serum concentrations of interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-α) in individuals with an inflammatory background. Effect sizes were estimated using weighted mean differences (WMD) and 95% confidence intervals across 32 randomized controlled trials (RCTs), alongside dose-response and subgroup analyses.
What was found
Curcumin/turmeric supplementation led to a statistically significant decrease in serum IL-1 (WMD = -2.33 pg/ml, 95% CI: -3.33 to -1.34, P < 0.001) and TNF-α (WMD = -1.61 pg/ml, 95% CI: -2.72 to -0.51, P < 0.001). Changes in IL-6 (WMD = -0.33 pg/ml, 95% CI: -0.99 to 0.34, P = 0.33) and IL-8 (WMD = 0.52 pg/ml, 95% CI: -1.13 to 2.17, P = 0.53) were not statistically significant. Dose-response modeling showed non-linear relationships for IL-1 and IL-8 alterations, and subgroup analyses showed variable effects depending on treatment dose, duration, and patient population.
Why it matters
This review distinguishes which specific inflammatory cytokines are modulated by curcumin, indicating targeted reductions in circulating IL-1 and TNF-α rather than generalized suppression across all major interleukins.
Limits
The total number of participants, specific medical conditions evaluated, and curcumin formulations/bioavailability enhancers used are not reported in the abstract. Subgroup analyses demonstrated diverse and inconsistent outcomes depending on dose, study duration, and patient population.
Cited by
- supports Curcumin lowers circulating TNF-alpha levels by almost 5 picograms per milliliter.