For Some, A Bit of Chocolate May Help Lower Risk of Heart Problems

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ANAHEIM, Calif. — Eating chocolate on a regular basis may reduce people's risk of heart problems, particularly among those with obesity, a large new study suggests.

The study analyzed information from nearly 150,000 U.S. veterans who participated in the Million Veteran Program, a large study that tracks veterans and their health over time. Among these participants, the average age was 64 years, and 90 percent were men. At the start of the study, none of the participants had coronary artery disease (CAD), a type of heart disease in which plaque builds up in the arteries that supply blood to the heart.

The participants were asked how often they ate a 1-ounce (28 grams) serving of plain chocolate (without extras such as nuts or caramel added). They were then followed to see if they experienced heart problems or "events" related to coronary artery disease, such as chest pain, a heart attack or heart failure.

After about 2.5 years, 4,055 people experienced a CAD-related event. Overall, the rates of these heart events per 1,000 people were as follows: 11.8 events among those who didn't consume any chocolate, 10.5 events among those who consumed 1 ounce of chocolate once per month, 10.1 events among those who consumed 1 ounce of chocolate once per week, 10.1 events among those who consumed 1 ounce of chocolate two to four times per week and 9.7 events among those who consumed 1 ounce of chocolate five or more times per week. [Top 10 Amazing Facts About Your Heart]

After the researchers took into account factors that might affect a person's risk of CAD — such as age, sex, race, physical activity levels and smoking habits — they found that eating a 1-ounce serving of chocolate five or more times a week was linked with an 11 percent decrease in the risk of CAD-related events. (Eating chocolate less frequently was not linked with a reduced risk of CAD-related events.)

The findings show that "there is a little bit of benefit" to eating chocolate regularly, in terms of lowering the risk of CAD-related events among these participants, said study co-author Yuk-Lam Ho, a researcher at the U.S. Department of Veterans Affairs. Ho presented the findings here yesterday (Nov. 12) at the American Heart Association's Scientific Sessions meeting.

When the researchers categorized people into three groups based on their body mass index (BMI), they found that only those with obesity (with a BMI over 30) had a lower risk of CAD-related events if they ate a 1-ounce serving of chocolate five or more times a week. The reduced risk was not seen in those who were overweight (with a BMI between 25 and 30) or normal or underweight (with a BMI under 25).

The findings add to a number of studies that suggest eating chocolate may reduce the risk of heart disease and stroke. However, many previous studies were smaller, so those were less stable, Ho said.

The reason chocolate was linked with a lower risk of CAD-related events only for people with obesity in the study is not clear. But it may be because the reduced risk was small, so it showed up only in people who had the highest risk for heart disease, Ho told Live Science. (People who are obese are known to be a higher risk for heart disease than those who are normal weight.)

It's important to note that although the new study found an association between eating chocolate and having a reduced risk for CAD-related events, it cannot prove that eating chocolate causes a reduce risk of CAD-related events.

Nor are the new findings a reason to gorge on chocolate, considering that the serving size used in the study was a single ounce of chocolate. (A regular-sized Hershey bar is about 1.5 ounces, or 43 grams.) A previous analysis published in 2015 in the journal Heart of nearly 160,000 people also found that eating up to 3.5 ounces (100 grams) of chocolate daily is linked with lowered risks of heart disease and stroke.

Because the new study included mainly older, white men, it's unclear if the results would apply to other populations, Ho said.

The new study did not distinguish between dark and milk chocolate. However, less processed or darker chocolates tend to have higher levels of antioxidants, which are the compounds in chocolate that are hypothesized to provide health benefits, according to previous research. Ho said she hopes that future studies involving this same group will look into how the type of chocolate affects the link between chocolate consumption and CAD-related events.

The findings have not yet been published in a peer-reviewed journal.

Original article on Live Science.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.