In the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a team of researchers led by Brigham and Women’s Hospital scientists examined whether cocoa flavanol and multivitamin-multimineral supplements prevent cardiovascular disease and cancer among older adults; while neither supplement significantly reduced the primary outcome of total cardiovascular events, people randomized to receive the cocoa flavanol supplement had a 27% lower rate of cardiovascular mortality.
Sesso et al. examined whether cocoa extract supplementation decreases total cardiovascular disease among older adults. Image credit: Sci-News.com.
“When we look at the totality of evidence for both the primary and secondary cardiovascular endpoints in COSMOS, we see promising signals that a cocoa flavanol supplement may reduce important cardiovascular events, including death from cardiovascular disease,” said Dr. Howard Sesso, a researcher in the Division of Preventive Medicine at Brigham and Women’s Hospital.
“These findings merit further investigation to better understand the effects of cocoa flavanols on cardiovascular health.”
“Previous studies have suggested health benefits of flavanols — compounds in several plant-based foods including cocoa, tea, grapes, and berries,” added Dr. JoAnn Manson, also from the Division of Preventive Medicine at Brigham and Women’s Hospital.
“COSMOS was not a chocolate trial — rather, it’s a rigorous trial of a cocoa extract supplement that contains levels of cocoa flavanols that a person could never realistically consume from chocolate without adding excessive calories, fat, and sugar to their diet.”
The COSMOS trial offered an opportunity to examine if a cocoa flavanol supplement might lead to longer-term reductions in clinical cardiovascular events. The study authors also looked for reductions in risk of cancer.
In addition, the study was designed to test a common multivitamin in the prevention of cancer and cardiovascular disease.
More than 21,000 participants were randomized to take daily capsules that contained 500 mg cocoa flavanols, a multivitamin tablet, neither or both.
The study found that cocoa flavanols reduced total cardiovascular events by 10%, but this was not statistically significant.
However, several secondary analyses provided broader support for a potential benefit of cocoa flavanols on cardiovascular events.
First, those receiving the cocoa flavanol supplement had a significant 27% reduction in death from cardiovascular disease.
Second, when the scientists took adherence to study pills into account, they saw a stronger, 15% reduction in total cardiovascular events and a 39% reduction in death from cardiovascular disease.
Third, a composite endpoint of major cardiovascular events, although not a trial focus, was also significantly reduced.
A daily multivitamin had no significant effect on total or individual cardiovascular events.
“Although our study suggests intriguing signals for cardiovascular protection with cocoa flavanols, any health benefits due to taking these supplements will need confirmation in a future trial,” Dr. Manson said.
“Our message for consumers is to eat a healthy, balanced diet, rich in natural food sources of flavanols, and to stay tuned as we further evaluate other important health outcomes in COSMOS,” Dr. Sesso added.
The results appear in two papers in The American Journal of Clinical Nutrition.
Howard D. Sesso et al. Effect of cocoa flavanol supplementation for prevention of cardiovascular disease events: The COSMOS randomized clinical trial. The American Journal of Clinical Nutrition, published online March 16, 2022; doi: 10.1093/ajcn/nqac055
Howard D. Sesso et al. Multivitamins in the prevention of cancer and cardiovascular disease: The COSMOS randomized clinical trial. The American Journal of Clinical Nutrition, published online March 16, 2022; doi: 10.1093/ajcn/nqac056