There are so many heart healthy benefits of dark chocolate, almost too many to list. A 100 gram bar with 70-85% cocoa contains iron, zinc, magnesium, manganese, copper, as well as plenty of potassium, phosphorus, selenium, and fiber.
Scientific researches have found that dark chocolate may improve blood flow and lower blood pressure. For instance, a 2015 study revealed that eating dark chocolate is associated with a lower risk for cardiovascular disease (CVD). The study suggests that up to 100 grams per day of dark chocolate may be associated with a lower risk of CVD.
Keep in mind, however, that 100 grams (3.5 ounces) is a fairly large amount, and does come with a hefty amount of calories (647 to be exact) as well as 42g of fat and 24g of sugar!