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Sweet dreams: eating chocolate prevents heart disease
- By Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing
ARCHIVED CONTENT: As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date each article was posted or last reviewed. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
If you’re a chocoholic, the news out of England is tantalizing: middle-aged and older adults who eat up to 3.5 ounces of chocolate a day (that’s more than two standard Hershey bars) seem to have lower rates of heart disease than those who spurn chocolate.
At least that was the conclusion of a study that followed the health of nearly 21,000 resident of Norfolk, England, for 11 years. Among those in the top tier of chocolate consumption, 12% developed or died of cardiovascular disease during the study, compared to 17.4% of those who didn’t eat chocolate. The results were published online in the medical journal Heart.
Desire vs. evidence
I’m a chocolate lover. My new favorite is an ice cream called Chocolate Therapy. The name doesn’t feel like a stretch, given the results of this study and many before it that have linked eating chocolate to a lower risk of heart disease.
Much as I’d like to believe in that connection, and get to work on my own personal Chocolate Therapy, we don’t yet know enough to put eating chocolate on a par with eating fruits, vegetables, and whole grains.
All of the large studies, including the one from Norfolk, are observational studies. That means the researchers asked questions about the participants eating habits, tracked their health, and made statistical connections. These kinds of studies can generate important insights. But they can’t prove cause and effect. It takes a randomized trial to do that.
It’s possible that people who like to eat chocolate do something else that offers heart protection, like eat a wide variety of healthful foods. One of the interesting things about this research is that participants in the non-chocolate group had higher average weight, more artery-damaging inflammation, more diabetes, were less physically active and had diets with the least amount of fat compared to chocolate eaters.
Is milk chocolate okay?
Most of the previous studies on the chocolate-heart connection found that only dark chocolate offered any cardiovascular protection. In the Norfolk study, any type of chocolate, including milk chocolate, seemed to have the same beneficial effect.
Scientists aren’t sure what it is about chocolate that seems to boost heart health. It may be related to flavonoids, a type of antioxidant produced by plants. Flavonoids are found in tea, red wine, blueberries, apples, pears, cherries, and nuts.
Flavonoids are particularly abundant in cacao beans—the seeds of the cacao tree. Fermenting, drying, and roasting cacao beans yields cocoa powder, which is used to make chocolate.
Flavonoids in cocoa have been shown to help lower blood pressure, improve blood flow to the brain and heart, prevent blood clots, and fight cell damage. They’ve also been shown to help thinking skills.
No chocolate prescription—yet
I routinely write my patients a prescription for exercise, and sometimes for eating more vegetables and fruits. I won’t be writing any prescriptions for chocolate in the foreseeable future.
But I won’t be telling them not to eat chocolate—in moderation of course. As the Norfolk study researchers concluded, “There does not appear to be any evidence to say that chocolate should be avoided in those who are concerned about cardiovascular risk.”
When it comes to chocolate or cocoa flavonoids, no recommended daily amounts have been set. The European Food Safety Authority suggests that 200 mg of cocoa flavonoids per day is a good target for the general population.
The amount of cocoa used in chocolate varies a lot. To find out how much you’re getting you’ll have to do some detective work. The amount of flavonoids in chocolate is not always listed.
Your best bet is to stick with dark chocolate. As a general rule, it has more cocoa and therefore more flavonoids than milk chocolate. It also has less unhealthy sugar and saturated fat.
The higher the cocoa content of the bar, the better it is for your health. Look for bars with 70% cocoa or more.
I’m going to stick with an ounce of dark chocolate every so often—with some Chocolate Therapy in between.
About the Author
Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
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