Chronic and acute effects of cocoa products intake on arterial stiffness and platelet count and function: A systematic review and dose-response Meta-analysis of randomized clinical trials

The findings of trials investigating the effect of cocoa products consumption on vascular stiffness and platelet are controversial. The aim of this study is to summarize the findings on the acute and chronic effects of different forms of cocoa on the risk factors of cardiovascular disease. We searched SCOPUS, Pub Med and Web of Science from inception to Jan 2020. Finally, the random-effect model was used to report the pooled effect sizes. Results are expressed as weighted mean difference (WMD) with 95% confidence intervals (CI).Overall, 41 trials were included, of which only 14 studies met the eligibility criteria for analysis, including 11 long-term RCTs (more than a week was considered as a chronic phase) and 7 short-term RCTs (less than a week was considered as an acute phase). According to the result of 11 long-term RCTs, cocoa products had a negative significant effect on pulse wave velocity; PWV (WMD: -0.33 m/s, P < 0.0001), Augmentation index; AIx (WMD: -4.50%, P = 0.001) but had no significant effect on platelet count (WMD: -10.41 10⁹/L, P = 0.053). Also, according to the results of 7 short-term RCTs, cocoa products had a negative significant effect on PWV (WMD: -0.27 m/s, P = 0.019), AIx (WMD: -4.47%, P = 0.003).Current study indicated the beneficial effect of acute and chronic consumption of cocoa-based products ingestion on platelet function and arterial stiffness in healthy adult regardless of age especially in male and for consumption (≤4 weeks) in the chronic intake and (≤120 minutes) in acute intake, but did not affect on platelet count. However, further studies are required to shed light on this issue.