Does dark chocolate or cocoa benefit your heart?

Dark chocolate with a high cocoa content has been linked to beneficial effects on the heart and blood vessels in multiple studies. Flavanols, the active compounds in cocoa, help relax blood vessels via nitric oxide, suppress inflammation, and reduce platelet clotting. How strong those effects are in practice has not yet been fully proven in humans; a portion of the evidence comes from laboratory and mechanistic studies.

What makes the health benefits of dark chocolate more concrete: in three large American cohort studies involving more than 192,000 participants, eating five or more portions of dark chocolate per week was linked to a 21% lower risk of type 2 diabetes. That is relevant for the heart, because diabetes substantially raises the risk of cardiovascular disease. For each additional portion per week, the risk falls by around 3%. The same large cohort studies also show favourable associations with blood pressure and vascular health, but this is observational research. No firm cause-and-effect conclusion can be drawn from it.

Dark chocolate contains saturated fat, but that does not appear to cancel out the beneficial effect. A comprehensive review concluded that dark chocolate, despite its fat content, is not linked to a higher risk of cardiovascular disease. What matters is the food as a whole, not any single component.

For milk chocolate the opposite is true. It showed no protective effect and was instead associated with weight gain. The beneficial effects are specific to dark chocolate with a high cocoa content. In addition, chocolate is calorie-dense: consuming it in too large amounts leads to weight gain, which is itself a risk factor for cardiovascular disease. Experts speak of 'moderate amounts', although an exact portion size is rarely defined.