Effects of purified anthocyanins supplementation on serum concentration of inflammatory mediators: A systematic review and dose–response meta‐analysis on randomized clinical trials

Abstract

AbstractAnthocyanins, due to their antioxidant effects, are candidates to reduce inflammation and the risk of inflammatory diseases. Therefore, through conducting a systematic review and meta‐analysis, we tried to find the effect of purified anthocyanins on serum levels of C‐reactive protein (CRP), interleukin‐6 (IL‐6), and tumor necrosis factor‐alpha (TNF‐α). Databases including, ISI Web of Science, Scopus, ClinicalTrials.gov, PubMed, and Cochrane Library were searched up to June 2023. The meta‐analysis was done by calculating mean differences and their standard deviations. Calculating the statistical heterogeneity of intervention effects was performed through I‐squared statistics and Cochran's Q test. The pooled estimate showed a significant decrease in serum levels of CRP, TNF‐α, and IL‐6 (weighted mean difference (WMD) = −0.12 mg/L, 95% confidence interval (CI) = −0.21 to −0.02, p = 0.013; WMD = −1.37 pg/mL, 95% CI = −1.79 to −0.96; p < 0.001; WMD = −1.43 pg/mL, 95% CI = −1.87 to −1.00; p < 0.001, respectively). Subgroup analysis results revealed purified anthocyanins significantly decreased serum levels of CRP among participants with serum levels of CRP≥1.52 mg/L, at‐risk/unhealthy status, and in trials with intervention duration ≥84 days, anthocyanins dose ≥320 mg/day, and sample size ≥85 subjects. Regarding TNF‐α and IL‐6, out results showed that there was a significant effect of purified anthocyanins on serum levels of TNF‐α and IL‐6 in most subgroups. The results of our study indicated that purified anthocyanins significantly decreased serum levels of CRP, TNF‐α, and IL‐6. However, further high‐quality studies are needed to firmly establish the efficacy of purified anthocyanins.