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Feeling guilty about those chocolate chip cookies at lunch? Think again! Those delicious morsels might be lowering your risk of atrial fibrillation, a heart condition linked to stroke and heart failure.

A new study out of Harvard’s T.H. Chan School of Public Health found that adults who eat 2 to 6 ounces of chocolate a week are up to 20 percent less likely to develop the disease.

Atrial fibrillation is the most common cause of an irregular heartbeat, called an arrhythmia, in the United States and affects 2 million to 6 million people, said Elizabeth Mostofsky, lead author of the study.


Researchers examined data collected on about 55,000 Danish men and women who took part in the Danish Diet, Cancer, and Health Study over 13½ years.

“Researchers collected a lot of detailed information on the participants. Information such as their lifestyle, diet, blood pressure, and cholesterol,” Mostofsky said. “That also included, coincidentally, how much chocolate they ate.”

Over the time participants were monitored, about 3,400 were diagnosed with atrial fibrillation, Mostofsky said.

When researchers looked at the data, they found that compared with those who ate less than 1 ounce of chocolate a month, people consuming 1 to 3 ounces a month lowered their risk of atrial fibrillation by 10 percent. Eating 1 ounce a week reduced the risk by 17 percent, and eating 2 to 6 ounces a week resulted in a 20 percent reduction.

Benefits leveled off somewhat with greater consumption.

The results were about the same for men and women.

For reference, there’s about an ounce of chocolate in six Hershey’s Kisses.

“We’re seeing some real health benefits from eating cocoa. Obviously, eating too much poses other risks, but chocolate, in moderation, can be part of a healthy diet,” Mostofsky said.

She stressed that, as sweet as chocolate companies might find her results, there’s no conflict of interest.


“We haven’t received any money from candy makers. This isn’t meant to drive up chocolate sales or anything like that,” she said.

Money for the study came from the National Heart, Lung, and Blood Institute; European Research Council; EU 7th Research Framework Program; and the Danish Cancer Society, among others.

Andrew Grant can be reached at andrew.grant@globe.com.