Cocoa Flavanols: Emerging Research Is Taking Us Deeper Inside the Cacao Bean

Consumer media have, for the past couple of years, been hailing chocolate (particularly dark chocolate) as offering such health benefits as lowered body-mass index and improved mood. Unfortunately for chocolate lovers everywhere, these claims for chocolate itself have not yet been sufficiently borne out by scientific research. What is coming to light, however, are some of the effects cocoa flavanols, bioactive compounds naturally present in the cacao bean, have on the human body.
The amount of flavanols in a cocoa-based product depends on various factors, including plant genetics, the method used for harvesting it, how the cocoa itself is processed, and how the final product is prepared. The effects of cocoa flavanols on human health may include improved vascular function and cholesterol levels in the general population, improved blood-vessel function in patients with kidney failure, and improved memory and cognition.
It is important to keep in mind, however, that the studies to date on these effects of cocoa flavanols have been small, and further evidence is needed to support them, in the form of large-scale randomized trials. To this end, the Cocoa Supplement and Multivitamin Outcomes Study (COSMOS), based at Harvard University-affiliated Brigham and Women’s Hospital and in collaboration with Mars Inc., is enrolling 18,000 participants and is the first large-scale, long-term randomized trial examining cocoa flavanols’ benefits. For this study, women 65 or older and men 60 or older will be randomly assigned to consume either 750 mg of cocoa flavanols per day in capsule form or an identical capsule containing a placebo. The researchers will follow the participants for four years and compare the numbers of heart attacks, strokes, and deaths in each group. Ancillary studies will be centered on potential benefits of cocoa flavanols on brain health, including memory, decision-making skills, mood, and cognitive performance, and on metabolic health.
JoAnn Manson, MD, chief of the Division of Preventive Medicine at BWH and co-leader of the COSMOS study, stated in press statements about COSMOS that the trial “builds on a decade of scientific evidence indicating that cocoa flavanols improve blood-vessel function, metabolic health, and cognition. The depth and breadth of this innovative trial are unprecedented.”
The following three slides summarize three of the more promising potential benefits cocoa flavanols may offer.

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