The link below goes to a study that shows dark chocolate that is rich in flavanols induced coronary vasodilatation and improved coronary vascular function in 11 heart-transplant recipients. Most people already know this but if you read further you notice a warning.
“There is a catch for dark-chocolate fans too. Dark chocolate can be deceptive. When chocolate manufacturers make confectionary, the natural cocoa solids can be darkened and the flavanols, which are bitter, removed, so even a dark-looking chocolate can have no flavanol. Consumers are also kept in the dark about the flavanol content of chocolate because manufacturers rarely label their products with this information.”
Click on the article below to read the article for yourself: