Long-Term Study Of Cocoa Flavanols Reveals Benefits For Cardiovascular Health

Participants in a study of cocoa flavanols were found to be less likely to die of cardiovascular events such as stroke.

<p>Cocoa beans, which are the basis of chocolate, contain flavanols that appear to have benefits for cardiovascular health. (Brigham and Women's Hospital)</p>

Chocoholics can rejoice because a new study has found that an essential component of the sweet treat can actually improve cardiovascular health. 

Cocoa flavanol, also known as flavan-3-ols, is an extract from cacao beans that reduces the probability of death from cardiovascular disease by 27 percent. 

The Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) is the first large-scale randomized trial that compares the benefits of using a cocoa flavanol supplement with those of using a multivitamin over three and a half years. 

While neither lessened the main causes of diminished cardiovascular health, subjects who took the cocoa flavanol were 27 percent less likely to die from heart attack, stroke, coronary revascularization, carotid artery disease, unstable angina, cardiovascular death and peripheral artery surgery. 

Whole roasted cocoa beans are displayed for tasting at Dandelion Chocolate on March 17, 2014, in San Francisco, California. A study on the health benefits of cocoa flavanols and how they can help prevent heart attacks and strokes has just been published, confirming that large concentrations of flavanols do reduce deaths due to cardiovascular events. (Justin Sullivan/Getty Images)

The study was conducted by scientists at Brigham and Women’s Hospital in Boston, Massachusetts. Their findings were published in The American Journal of Clinical Nutrition

“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 lead author Howard Sesso. “These findings merit further investigation to better understand the effects of cocoa flavanols on cardiovascular health.”

Cocoa seed extracts, or flavanols, are already available on the market from various manufacturers and vendors that tout their benefits for blood circulation and brain health. 

Flavanols are found in beverages and foods other than chocolate, including berries, grapes and tea, according to the study. 

Flavanols can also be found in berries, grapes and tea. Red and black grapes have higher concentrations of flavonoids, which cause the darker color. (Kiran Ridley/Getty Images)

“COSMOS was not a chocolate trial,” said study co-author JoAnn Manson. “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.”

While previous studies determined that cocoa flavanols are beneficial for blood pressure and blood vessel dilation, the COSMOS study is the first to evaluate whether as a supplement, they might offer long-term benefits to cardiovascular disease patients.  The study also examined whether a commonly used multivitamin can fight cardiovascular disease and cancer. 

“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,” said Manson. Sesso called on consumers to “eat a healthy, balanced diet, rich in natural food sources of flavanols” and expect to hear about further benefits of the COSMOS study. 

In the study, over 21,000 participants were randomized to take capsules containing 500 mg of cocoa flavanols or a multivitamin tablet or both or neither. While the researchers initially determined that the flavanols reduced the total number of cardiovascular events by 10 percent and were not statistically significant, further analysis showed that participants had a 27 percent reduction in death from cardiovascular disease, which was significant.

A COSMOS trial study pills pack. Some participants were given either a multivitamin or a flavanol supplement, while others were given both or neither. (MARS)

Also, when participants faithfully consumed the pills, the researchers observed a 15 percent reduction in total cardiovascular events and a 39 percent drop in death from cardiovascular disease. 

The daily multivitamin had no significant effect on cardiovascular events, according to the study, and there were no safety concerns for the multivitamin or cocoa flavanols. Neither had a significant effect on total invasive cancer, but the researchers will follow the study participants to determine whether there are any long-term effects on death and cancer. 

The team may also study how the supplements influence eye disease, cognitive decline, falls and other effects of aging in the future. 

 The European Food Safety Authority noted in 2014 that products containing 200 mg of cocoa flavanols “help maintain the elasticity of blood vessels, which contributes to normal blood flow.”

Edited by Siân Speakman and Kristen Butler