Dark Chocolate Reduces ACE Activity and May Lower Heart Attack Risk

Eating as little as 75 grams of dark chocolate reduces the activity of angiotensin-converting enzyme (ACE) while increasing levels of nitric oxide (NO), which suggests that including chocolate in the diet may ultimately help reduce hypertension and its related risk of cardiovascular disease.

Investigators at Linköping University (Sweden) wanted to determine if cocoa extract and dark chocolate would influence ACE and NO in human endothelial cells (in vitro) and in healthy volunteers (in vivo).

ACE activity was analyzed with a commercial radioenzymatic assay and measured in human endothelial cells from umbilical veins (HUVEC) after a 10-minute incubation with cocoa extract. NO was measured after 24 hours incubation. In 16 healthy volunteers ACE activity and NO were measured at baseline and after 30, 60 and 180 minutes after a single intake of 75 g dark chocolate containing 72% cocoa. The volunteers were not tobacco users and were not allowed to take any pharmaceuticals for the two weeks prior to the experiment. During the last two days, they were not allowed to eat chocolate or any foods containing similar compounds, including many kinds of berries and fruits, nor could they drink coffee, tea, or wine.

Results published in the October 14, 2010, online edition of the Journal of Cardiovascular Pharmacology revealed that in the HUVEC significant inhibition of ACE activity and significant increase of NO were seen. In the human volunteers, a significant inhibition of ACE activity (mean 18%) three hours after intake of dark chocolate was measured, but no significant change in NO was seen.

"We have previously shown that green tea inhibits the enzyme ACE, which is involved in the body's fluid balance and blood pressure regulation. Now we wanted to study the effect of cocoa, since the active substances catechins and procyanidines are related,” said first author Dr. Ingrid Persson, professor of pharmacology at Linköping University. "Our findings indicate that changes in lifestyle with the help of foods that contain large concentrations of catechins and procyaninides prevent cardiovascular diseases.”

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