Dark chocolate contains 50-90% cocoa solids, cocoa butter, and sugar, whereas milk chocolate contains anywhere from 10-50% cocoa solids, cocoa butter, milk in some form, and sugar. Though dark chocolate should not contain milk, there may be traces of milk from cross-contamination during processing, as the same machinery is often used to produce milk and dark chocolate. Lower quality chocolates may also add butter fat, vegetable oils, or artificial colors or flavors. White chocolate does not contain any cocoa solids and is made simply of cocoa butter, sugar, and milk.Cocoa is rich in plant chemicals called flavanols that may help to protect the heart. Dark chocolate contains up to 2-3 times more flavanol-rich cocoa solids than milk chocolate. Flavanols have been shown to support the production of nitric oxide (NO) in the endolethium (the inner cell lining of blood vessels) that helps to relax the blood vessels and improve blood flow, thereby lowering blood pressure.Dark chocolate is loaded with nutrients that can positively affect your health. Made from the seed of the cocoa tree, it is one of the best sources of antioxidants on the planet. Studies show that dark chocolate (not the sugary crap) can improve your health and lower the risk of heart disease.