Do you enjoy an occasional -- or frequent -- square or two of dark chocolate? If so, you are far from alone. Dark chocolate is gaining a reputation as a heart-healthy food, and research suggests that there might be some substance behind those claims. But while some chocolate lovers feel virtuous, others may view their habit as a guilty pleasure -- emphasis on the guilty. What is the best way to think about chocolate?
"I see it just as a pleasure, nothing to feel guilty about," says Ginger Hultin, M.S., R.D.N., owner of Champagne Nutrition in Seattle and a spokesperson for the Academy of Nutrition and Dietetics. "Cocoa contains antioxidants in addition to magnesium, potassium, zinc, and iron. Plus, studies have shown that there could be some benefit to consuming chocolate or cocoa for the cardiovascular system, including potentially lowering blood pressure."
The power of flavanols
Dark chocolate's health halo comes from its cocoa -- specifically its cocoa flavanols. Flavanols are a type of polyphenol, and polyphenols are one group of phytochemicals. Many fruits and vegetables contain flavanols, but they are especially rich in tea, wine, and cocoa. Some research suggests that they have anti-inflammatory and antioxidant properties and may help protect against cardiovascular disease, which affects both the heart and brain.
For example, research has found that even two weeks of eating of dark chocolate or other flavanol-rich cocoa products is better than a placebo for lowering blood pressure in people who already have high blood pressure, although not to normal levels. In 2013, the European Food Safety Authority approved the claim that cocoa flavanols help maintain normal blood pressure.
Cocoa vs. chocolate
Data from the long-running Physicians' Health Study suggests that chocolate intake is associated with a reduced risk of developing Type 2 diabetes in younger and normal-weight men. However, take those findings with a grain of salt, because they were based on a single question about average yearly intake of chocolate that didn't ask what type of chocolate--white (which contains no cocoa), milk, or dark, says Howard Sesso, Sc.D., M.P.H., an associate professor of preventive medicine at Brigham and Women's Hospital in Boston. "If we assume that any benefits from cocoa are attributable to its flavanol content, then dark chocolate should in theory confer greater benefits than milk chocolate."
While a number of smaller studies have demonstrated that cocoa can help lower blood pressure, blood sugar, and cholesterol, the big question is whether those payoffs will actually help prevent cardiovascular disease down the road. As part of the COSMOS, or COcoa Supplement and Multivitamin Outcomes Study, Sesso and other researchers are investigating whether taking daily supplements of 600 mg of cocoa flavanols -- not chocolate itself -- reduces the risk for developing heart disease and stroke, as well as cancer.
Is the devil in the dose?
What does that mean for the average person who enjoys chocolate and hopes they're getting some health benefit from it? Sadly, results from the large European Prospective Investigation of Cancer, Norfolk (EPIC-Norfolk) study suggest that the amount of flavanols that the average person in Europe or the United States consumes is unlikely to do much to reduce risk of cardiovascular disease.
Of course, how much you need to consume to reap benefits isn't even clear. Some research suggests 200 milligrams of cocoa flavanols daily, about the amount in 2.5 grams of high-flavanol cocoa powder, or a third of an ounce (10 grams) of high-flavanol dark chocolate. However, other research has found that a daily dose of 900 milligrams of flavanols may be necessary.
Further muddying the waters is the fact that, even though cocoa is a key ingredient in milk and dark chocolate, you can't really be sure how many flavanols you're getting. "Product packaging does not specify amounts of cocoa flavanols, only percent cacao," Sesso says. "Variable processing of the cocoa bean makes it difficult to equate percent cacao with cocoa flavanol content."
The merits of moderation
So far, results from clinical trials looking at various cocoa or chocolate products and possible health benefits are promising, but very preliminary. "Our ongoing COSMOS trial will eventually provide greater clarity on clinical outcomes," Sesso says, adding that it's unclear whether bioactive components of the cocoa bean other than flavanols may play a role.
In the meantime, because chocolate products are typically high in calories and fat, Sesso says it's best to not think of dark chocolate as a health food, per se. "Moderation is key; if someone enjoys eating chocolate, it should be done in moderation along with other foods."
So for now, it's best to not put all your flavanol -- or phytochemical -- eggs in a dark chocolate basket. For a phytochemical boost, take a broader, more balanced approach. "We get different phytochemicals and antioxidants from a wide variety of foods," Hultin says. "Including different colors of fruits, veggies, whole grains and beans is the best way to gain access to antioxidants that could support health." That said, she does recommend enjoying a bit of chocolate or cocoa. "I put cocoa powder in my smoothies for an added boost of flavor, nutrients and antioxidants."
(Environmental Nutrition is the award-winning independent newsletter written by nutrition experts dedicated to providing readers up-to-date, accurate information about health and nutrition in clear, concise English. For more information, visit www.environmentalnutrition.com.)