Cocoa flavanol supplementation reduces risk for cardiovascular death

Study participants who were randomly assigned to receive cocoa flavanol supplementation had a 27% lower risk for cardiovascular death than those assigned to placebo, according to data published in The American Journal of Clinical Nutrition.

“We see a lot of promise here,” Howard D. Sesso, ScD, MPH, an associate professor in the division of preventive medicine at Brigham and Women’s Hospital, told Healio. “We need to learn more about what these flavanols can do in terms of cardiovascular health.”

Cocoa flavanols are believed to be the most relevant bioactive component of a cocoa bean, according to Sesso. Flavanols are also found in tea, grapes, wine and several types of berries. Previous research indicates that flavanols may counteract cognitive decline and improve brain function.

As part of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) trial, Sesso and colleagues assessed whether cocoa flavanols or multivitamins can prevent CVD and cancer. In total, 21,442 U.S. adults were enrolled in the randomized, double-blind, placebo-controlled, two-by-two factorial trial; 12,666 of the participants were women aged 65 years and older and 8,776 were men aged 60 years and older. The participants were randomly assigned to receive daily capsules that contained 500 mg cocoa flavanols, a multivitamin tablet (GlaxoSmithKline Consumer Healthcare), neither or both.

Cocoa flavanol supplementation

The flavanol supplementation intervention was conducted from June 2015 to December 2020. The primary outcome was a composite of confirmed incident total cardiovascular events, including myocardial infarction, stroke, coronary revascularization, cardiovascular death, carotid artery disease, peripheral artery surgery and unstable angina. The participants were followed for a median of 3.6 years.

Overall, there were no safety concerns with cocoa flavanols, according to Sesso and colleagues. The researchers reported that cocoa flavanols reduced total cardiovascular events by 10%. However, this finding was not statistically significant.

Meanwhile, secondary analyses revealed that participants receiving the cocoa flavanol supplementation had a significant 27% reduction in death from CVD (HR = 0.73; 95% CI, 0.54-0.98). There was an emerging signal of benefits that started to evolve around under 2 years of follow up, Sesso said.

Compliance-based analyses revealed a stronger, 15% reduction in total cardiovascular events and a 39% reduction in death from CVD among those who took at least 75% of their supplementation, according to the researchers.

Multivitamin supplementation

Among participants randomly assigned to the multivitamin arm, Sesso and colleagues reported no significant effect on breast cancer, colorectal cancer or all-cause mortality. However, there was a protective effect of the multivitamin on lung cancer (HR = 0.62; 95% CI, 0.42-0.92). The researchers noted that the follow-up period was likely too short to detect associations with cancer risk.

“Certainly, for multivitamins, we wouldn't recommend taking those specifically for disease prevention, but perhaps have them as part of a larger strategy of a heart-healthy diet,” Sesso said. “It’s critically important to maintain a heart-healthy diet, but that alone will not necessarily get useful levels of the cocoa flavanols that we tested in COSMOS.”

References:

Sesso HD, et al. Am J Clin Nutr. 2022;doi:10.1093/ajcn/nqac055.

Sesso HD, et al. Am J Clin Nutr. 2022;doi:10.1093/ajcn/nqac056.