Randomized study of the effects of cocoa-rich chocolate on the ventricle-arterial coupling and vascular function of young, healthy adults.

Objectives: The aim of this study was to evaluate and explore the benefits of long-term dark chocolate intake in young, healthy adults by measuring cardiovascular function.

Methods: A randomized study was conducted with 30 healthy participants ages 18 to 27 y. Half of the participants ingested a 20-g dose of lower cocoa chocolate (LCC; ∼55%; 12.6 ± 1.4 mg equivalent of epicatechin/g) and the others ingested a daily dose of 20 g of higher cocoa chocolate (HCC; ∼90%; 18.2 ± 2.6 mg equivalent of epicatechin/g). A baseline evaluation was performed before the participants started ingesting the assigned chocolate for a 30-d period, after which a final evaluation was performed. Each evaluation included heart ultrasonography, carotid-femoral pulse wave velocity (PWV) and carotid pulse wave analysis, flow-mediated slowing (FMS), and an analysis of the ventricular-arterial coupling (VAC), which reflects the matching between the aorta and the left ventricle (ratio of arterial elastance to left ventricle elastance).

Results: The baseline evaluation presented similar values within normal range in both groups. The positive vascular effects were overall more distinct in the group eating the HCC. No structural modifications on the heart were found after the intervention, notwithstanding cardiac function was improved on certain functional parameters in the HCC group only. A statistically significant improvement was depicted over the brachial and central systolic and pulse pressures in the HCC group, and a trend for improvement in the reflected waves component (Aix) and the FMS was also observed in the HCC, but not in the LCC group. VAC parameters were similar at baseline between groups, but showed a significant improvement in the HCC group after intervention, increasing from 0.674 to 0.719 (P = 0.004), so that the post-intervention VAC was significantly higher in the HCC group than in the LCC group (P < 0.05). In addition, significant variation was observed in both groups regarding arterial and left ventricle elastances, stroke work, and potential energy, with greater mean differences identified in the HCC group.

Conclusion: This study demonstrated that regular consumption of HCC has beneficial effects on the cardiovascular system in young, healthy adults, improving vascular function by reducing central brachial artery pressures and promoting vascular relaxation, and thus enhancing the matching of the arterial system with the left ventricle.