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Why chocolate protects against heart disease

Cacao has a protective effect against cardiovascular disease, several studies have shown. The cause has now been made clear by researchers at Linköping University. When a group of human test subjects got to munch on a hearty portion of dark chocolate, an enzyme in the body that contributes to increasing blood pressure was inhibited.

Behind the study, the results of which are now being published in the Journal of Cardiovascular Pharmacology, is a group of medical researchers under the leadership of Ingrid Persson.

“Earlier, we showed that green tea inhibits the enzyme ACE, which is involved in the body’s fluid balance and regulation of blood pressure. Now, we wanted to study the effects of cacao, since the active substances catechins and procyanidins are related,” says Persson.

Researchers recruited 16 healthy volunteer test subjects for the study. They didn’t smoke or take snuff, and were not allowed to take any medicines for two weeks. For the final two days, they were not allowed to eat chocolate or anything that contained similar substances, such as many types of berries and fruits, or drink coffee, tea, or wine.

During the study, everyone in the group - ten men and six women between 20 and 45 - got to eat 75 grams of dark unsweetened chocolate with a cacao content of 72 percent. In order to analyse what happened with the enzyme ACE, blood samples were taken beforehand and then a half-hour, an hour, and three hours afterwards.

In the samples taken after three hours, a significant inhibition of ACE activity was detected. The average value was 18 percent lower activity than before the cacao dose, fully comparable with the effect of medicine that inhibits ACE and which is used as a primary treatment for high blood pressure.

When the enzyme’s activity decreases, blood pressure sinks over the long term. As expected, no such effect was seen in the test subjects. To demonstrate this, the study needs to continue longer.

Despite Persson being a medicinal researcher, new medicine is not the primary goal of her studies.

“Our results indicate that lifestyle changes, with the help of foods that contain high catechin and procyanidin content, prevent cardiovascular disease,” she says.


Effects of cocoa extract and dark chocolate on angiotensin-converting enzyme and nitric oxide in human endiothelial cells and healthy volunteers by Ingrid A-L. Persson, Karin Persson, Staffan Hägg and Rolf G.G. Andersson. Journal of Cardiovascular Pharmacology Publish Ahead of Print, Nov. 2010.

Contact information:

Ingrid Persson +46 10-1031052, ingrid.persson@liu.se

Therese Winder 2010-11-18

Page manager: therese.winder@liu.se
Last updated: 2010-11-18