Skip to main content

COSMOS: Large-scale trial shows promise of cocoa flavanols for reducing cardiovascular risk

COSMOS: Large-scale trial
By: Dr. Hagen Schroeter, Mars Edge Chief Science Officer

In my role as Chief Science Officer at Mars Edge I’m often asked, “What are flavanols?” and, “How do you know they’re healthy?” My answer to the first question is not difficult: Flavanols are natural compounds found in many plant-based foods, including tea, berries, apples, cocoa, and other fruits and vegetables. 

The answer to the second question has been the focus of Mars Edge’s research program for the past 20 years. Building on our findings and those of other research teams around the world, scientists at the Brigham and Women’s Hospital set themselves a remarkable, timely and super interesting task. Almost 8 years ago, they set out to rigorously investigate the long-term effects of cocoa flavanol intake on cardiovascular disease risk and cardiovascular death at a scale and duration that had never been attempted. To do so, the researchers designed and undertook the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a randomized, double-blind, placebo-controlled trial, which became the largest clinical dietary intervention trial investigating the impact of flavanols on health.

Very early on in the project, we were approached by the principal investigators of what later became COSMOS. They asked whether Mars would support their study, given our extensive research on cocoa flavanols and health, and our ability to produce a standardized flavanol-containing test materials suitable for a clinical trial at this scale and duration. We agreed, and supported COSMOS by providing an unrestricted, investigator-initiated grant, which included infrastructure support and a donation of study pills and packaging. The pills contained a specially developed cocoa extract, not chocolate, which is not a reliable source of flavanols, nor was it the focus of the study. Given the nutritional composition of chocolate, it is not appropriate to recommend the daily consumption of it as a food intended to support health. 
The National Institutes of Health (NIH) and Pfizer Consumer Healthcare (now part of GSK Consumer Healthcare) also supported the trial. 

First results from the COSMOS trial 


The first results from COSMOS have just been published in The American Journal of Clinical Nutrition. Based on the information provided in the paper by Sesso and Manson et al. [Ref], we have put together an overview of the results in the infographic below. As one of my main research areas for the last two decades has focused on investigating flavanols, I am thrilled that COSMOS was able to support at scale a role for flavanols in heart health and cardiovascular disease risk reduction. 

To quote Dr. Howard Sesso, ScD, MPH, of Brigham and Women’s Hospital and one of the principal investigators of COSMOS, “We see promising signals that a cocoa flavanol supplement may reduce important cardiovascular events, including death from cardiovascular disease.” [Ref]  The results show that when including all participants in the data analysis, the reduction of total cardiovascular events was not statistically significant, but there was a significant 27% reduction in cardiovascular death. When the investigators excluded from the data analysis those participants who admitted to not taking their study pills in accordance with the study protocol, the results demonstrated that the cocoa flavanol supplement group had a statistically significant 15% reduction in  total cardiovascular events and a 39% reduction in cardiovascular deaths.

Even though I fully agree with the authors of the study, who underscore the need for additional research and a careful interpretation of the COSMOS outcomes, I am also excited by the seminal and novel insights COSMOS generated, and the fact that the trial shows promise for flavanols in reducing cardiovascular disease risk, a major health challenge globally. This is just the first of many scientific papers likely to be published about the outcomes of COSMOS, because the trial also looked at other outcomes and included sub-studies focused on cognition, eye health, healthy aging, to name just a few. So I am excited what else we may learn, and I am sure that COSMOS will become a landmark study in nutrition.