Background: This #DoesItWorkSummary is based on the findings of a Cochrane Systematic Review published in April 2017 [1]. Cardiovascular disease (CVD) is the number one cause of death in the world, and high blood pressure (hypertension) plays the role of a major contributor to CVD, contributing to about 50% of cardiovascular events (including myocardial infarction and stroke). The interest in cocoa consumption as a possible approach for blood pressure reduction started with the observation that an island population in Central America, the Kuna Indians, had a remarkably low rate of hypertension that could be related to their high cocoa intake (several cups of cocoa drink daily and incorporation of cocoa into many recipes) [2]. Possible mechanism explaining this observation is that cocoa is rich of flavanols, which increase the formation of endothelial nitric oxide, a mediator molecule causing vasodilation resulting in blood pressure reduction [3]. A systematic evaluation of the available human trial data was performed to get overview if cocoa intake is indeed able to reduce blood pressure.
Findings: Analyzed were 35 trials involving 1804 people [1]. The analyzed studies were randomized controlled trials, in which the participants were randomly assigned to daily receive chocolate or other cocoa-rich products (altogether forming the “cocoa intervention” group) or to receive “placebo” low‐flavanol products (the later forming the “control” group of people that were used for comparison). The mean daily intake of flavanols was 670 mg, for 2 to 18 weeks. There was moderate‐quality evidence that flavanol‐rich chocolate and cocoa products cause a small (2 mmHg) reduction in both systolic and diastolic blood pressure. The cocoa products were generally well tolerated, with minor part of the participants having mild undesired effect such as gastrointestinal complaints and nausea.
References
1 Ried, K., Fakler, P. and Stocks, N.P. (2017) Effect of Cocoa on Blood Pressure. Cochrane Database of Systematic Reviews, John Wiley & Sons, Ltd. https://doi.org/10.1002/14651858.CD008893.pub3.
2 K Hollenberg, N. (2006) Vascular Action of Cocoa Flavanols in Humans: The Roots of the Story. Journal of cardiovascular pharmacology, 47 Suppl 2, S99-102; discussion S119–21. http://www.ncbi.nlm.nih.gov/pubmed/16794463.
3 Fisher, N.D.L., Hughes, M., Gerhard-Herman, M. and Hollenberg, N.K. (2003) Flavanol-Rich Cocoa Induces Nitric-Oxide-Dependent Vasodilation in Healthy Humans. Journal of hypertension, 21, 2281–6. https://doi.org/10.1097/01.hjh.0000084783.15238.eb.
Keywords: #DoesItWorkSummary, cocoa, blood pressure reduction, health, chocolate, flavanol, randomized controlled trials, Kuna Indians, myocardial infarction and stroke, diet, nutrition, hypertension, cardiovascular disease (CVD), Cochrane Systematic Review, science.
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