Is dark chocolate actually healthy?

Dark chocolate’s purported benefits are ascribed to compounds called flavanols, which are particularly abundant in cocoa.

EVEN YOUNG children know that chocolate is a treat, to be savoured on special occasions. But the “dark” variety, which has more cocoa, is touted as healthier and even as a health-booster. Dark chocolate, it is suggested, can alleviate all manner of problems, from high blood pressure to depression, while improving mental acuity. Many studies, often paid for by Big Chocolate, hint this may be true. Sadly, the best research debunks the idea.

Representative image.(Unsplash)

Dark chocolate’s purported benefits are ascribed to compounds called flavanols, which are particularly abundant in cocoa. In randomised controlled trials (the gold-standard type of study) researchers have looked at the health effects of capsules containing flavanols, as well as of consuming flavanol-rich foods such as cocoa products, coffee, tea, berries, grapes and apples. Some trials have found beneficial effects, for example on blood pressure. But results overall have been inconsistent. Moreover, these trials typically last just a few weeks, so they may not reflect the consequences of sustained consumption.

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Observational studies, which ask about diet rather than dictating it, have sometimes found that those who eat more flavanols, either from various foods or specifically from dark chocolate, are healthier. (They are less likely to develop diabetes, for example.) But such individuals may have other things going for them, too—for example, higher incomes that let them buy pricey stuff like dark chocolate. Work published in 2024 found people who ate lots of dark chocolate were less likely to smoke than those who ate little.

A big randomised trial called COSMOS, set up in 2015 in America, was intended to deal with these shortcomings. It measured the effects of daily cocoa-extract supplements containing 500mg of cocoa flavanols. (To get that dose you would need to eat between 50g—or half a bar—and 280g of dark chocolate, depending on its flavanol concentration.) Participants, who were in their 60s or older, took the capsules for a median of 3.6 years. Flavanols made no difference to rates of new cases of diabetes, serious circulatory problems such as heart attacks and strokes, cancer or cognition. They did, however, lead to a 27% reduction in deaths from cardiovascular disease.

Alas, this positive result is not proof that dark chocolate is heart-healthy. Getting those 500mg of flavanols from it means consuming lots of sugar, which is added lavishly by manufacturers to counter the bitterness of cocoa. It also means consuming upward of half (for men) or 70% (for women) of the recommended daily maximum of saturated fats, which are bad for the heart because they increase artery-clogging cholesterol. A better option for adding cocoa flavanols to your diet may be cocoa powder or ground cacao beans (often called nibs). All told, though, the healthiest flavanol-boosting strategy is to eat more fruits, vegetables, nuts and legumes—and to put the kettle on.

Two apples, a portion of nuts and a large serving of strawberries provide roughly 500mg of flavanols. So do two to three cups of green tea. If you decide to treat yourself to some chocolate every now and then, don’t sweat about finding the darkest variety. Some very dark chocolates contain few flavanols, whereas some milk varieties have lots. Sadly for chocoholics, the health claims for dark chocolate come from wishful thinking and sly marketing, not the findings of science.

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