Effect of cocoa products on blood pressure: Systematic review and meta-analysis

Background Cocoa products such as dark chocolate and cocoa beverages may have blood pressure (BP)-lowering properties due to their high content of plant-derived flavanols. Methods We performed a meta-analysis of randomized controlled trials assessing the antihypertensive effects of flavanol-rich cocoa products. The primary outcome measure was the change in systolic and diastolic BP between intervention and control groups. Results In total, 10 randomized controlled trials comprising 297 individuals were included in the analysis. The populations studied were either healthy normotensive adults or patients with prehypertension/stage 1 hypertension. Treatment duration ranged from 2 to 18 weeks. The mean BP change in the active treatment arms across all trials was 4.5mmHg (95% confidence interval (CI), 5.9 to 3.2, P <0.001) for systolic BP and 2.5mmHg (95%CI, 3.9 to 1.2, P <0.001) for diastolic BP. Conclusions The meta-analysis confirms the BP-lowering capacity of flavanol-rich cocoa products in a larger set of trials than previously reported. However, significant statistical heterogeneity across studies could be found, and questions such as the most appropriate dose and the long-term side effect profile warrant further investigation before cocoa products can be recommended as a treatment option in hypertension.