Findings: Why Dark Chocolate Is Good for Heart Health

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Health recommendations from experts often include exercising more and eating more whole grains, but perhaps one of the more welcome advances in medical research has been the declaration that chocolate is good for us. Now, new research may help explain why indulging in the sweet treat helps our heart health.

Researchers from Linkoping University in Sweden have found that eating dark chocolate inhibits the action of an enzyme nicknamed ACE (formally known as the angiotensin-converting enzyme), which is involved the body's fluid balance and helps regulate blood pressure.

The results are based on a study of 16 brave volunteers, ages 20 to 45, who ate 75 grams (about 2 1/2 ounces) of dark chocolate with a cocoa content of 72 percent. Researchers led by Ingrid Persson, a pharmacology professor at the university, measured the level of ACE activity in the volunteers' blood before they ate the chocolate, and again 30 minutes, one hour and three hours afterward.

Three hours after eating the chocolate, the ACE activity in the volunteers' blood was 18 percent lower than before they gobbled the goodies — a change comparable to that of blood-pressure lowering drugs designed to inhibit ACE.

"I was surprised by the great effect," Persson told MyHealthNewsDaily. Previous work had shown chocolate had positive effects on cardiovascular health, but scientists didn't know the mechanisms behind these effects, she said.

ACE plays an important role in the hormone system that regulates the kidneys' excretion of water, which helps to regulate blood pressure, she said. High levels of ACE activity have been associated with hardening of the arteries and other cardiovascular diseases.

In general, when the activity of the enzyme declines, blood pressure decreases, though the researchers did not conduct their study over a long enough time period to observe this effect, nor did they directly measure blood pressure, Persson said.

In 1996, studies in the journal Lancet showed that compounds in cocoa — called flavonoids — interacted with LDL cholesterol (the bad kind), which suggested chocolate could help prevent the hardening of arteries. Further work showed chocolate had anti-inflammatory properties, and some studies showed it lowered blood pressure, but none specifically demonstrated how it worked, the researchers wrote.

The study was published online in November in the Journal of Cardiovascular Pharmacology, and was funded by the university.

Karen Rowan
Karen Rowan
Health Editor
Karen came to LiveScience in 2010, after writing for Discover and Popular Mechanics magazines, and working as a correspondent for the Journal of the National Cancer Institute. She holds an M.S. degree in science and medical journalism from Boston University, as well as an M.S. in cellular biology from Northeastern Illinois University. Prior to becoming a journalist, Karen taught science at Adlai E. Stevenson High School, in Lincolnshire, Ill. for eight years.