Cardiovascular Effects of Flavanol-Rich Chocolate in Patients With Heart Failure

Study Questions:

Does flavanol-rich chocolate (FRC) improve cardiovascular function in patients with congestive heart failure (CHF)?


This was a double-blind, randomized, placebo-controlled trial in 20 patients with CHF. Patients were randomized to commercially available FRC or cocoa-liquor-free control chocolate (CC). All patients had stable CHF (New York Heart Association class ≥II) and an ejection fraction <50%. Outcomes of interest included short-term endothelial and platelet function, measured 2 hours after ingestion of a chocolate bar, and long-term endothelial and platelet function, measured after 4 weeks of daily consumption of two chocolate bars. Endothelial function was assessed noninvasively by flow-mediated vasodilatation of the brachial artery.


No significant differences in regard to baseline characteristics and risk factors were noted between the two groups. No participants experienced changes in CHF status or in weight during the study. Flow-mediated vasodilatation significantly improved from 4.98 ± 1.95 to 5.98 ± 2.32% (p = 0.045 and 0.02 for between-group changes) 2 hours after intake of FRC to 6.86 ± 1.76% after 4 weeks of daily intake (p = 0.03 and 0.004 for between groups). No effect on endothelial-independent vasodilatation was observed. Platelet adhesion significantly decreased from 3.9 ± 1.3 to 3.0 ± 1.3% (p = 0.03 and 0.05 for between groups) 2 hours after FRC, which was not sustained at 2 and 4 weeks. Cocoa-liquor-free CC had no effect, either on endothelial function or on platelet function. Blood pressure and heart rate did not change in either group.


The investigators concluded that FRC acutely improves vascular function in patients with CHF. A sustained effect was seen after daily consumption over a 4-week period, even after 12-hour abstinence. These beneficial effects were paralleled by an inhibition of platelet function in the presence of FRC only.


The beneficial effects of flavanol-rich foods, including chocolate, have been of interest to cardiovascular researchers for some time. This study adds further data in suggesting a benefit of FRC in patients with heart failure. However, this study is small, and larger studies with additional outcomes should be considered. In the meantime, given the holiday season, perhaps FRC in moderation could be considered a cardiac-healthy treat.

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Polyphenols, Heart Failure, Cacao

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