The effect of grape products containing polyphenols on C-reactive protein levels. - GreenMedInfo Summary
The Effect of Grape Products Containing Polyphenols on C-reactive protein Levels: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
Br J Nutr. 2020 Sep 14:1-41. Epub 2020 Sep 14. PMID: 32921322
Although grape polyphenols can decrease chronic inflammations, their effect on C-reactive protein (CRP) levels is still controversial. So, this meta-analysis was conducted to investigate the effect of grape products containing polyphenols on CRP concentrations. In order to collect the relevant randomized controlled trials (RCTs), the data bases of PubMed, Scopus, Web of Science, and Google Scholar were searched up to March 30, 2020. The random-effects model, standardized mean difference, and 95% confidence interval were applied in data analysis. Meta-analysis was conducted over 17 eligible RCTs containing a total of 668 participants. The study registration number is CRD42018110169. Based on the results, grape products containing polyphenol decreased the CRP levels significantly (SMD = -0.229; 95% CI: -0.41, -0.05; P = 0.013). The sensitivity analysis was performed by removing each individual study and the results did not change. According to the subgroup analysis, higher doses of grape polyphenols (˃ 500 mg/d) and longer intervention periods (≥ 12 wk) had significant effects on CRP levels. Furthermore, grape polyphenols significantly reduced the CRP levels in patients with a clinical condition. In the same vein, grape seed extract and other grape products, such as grape extract, juice, andraisin, decreased the CRP levels significantly. According to the meta-regression results, the CRP level depends on the dose and duration of the grape polyphenols supplementation. Based on the findings, grape products containing polyphenols had a significant effect on CRP levels. Further well-designed and long-term clinical trials are highly recommended to achieve more comprehensive and accurate results.