Dark chocolate is any chocolate that has a high percent of cocoa solids - it's different for every country for what is legally considered a high percent, but generally 70% or higher is considered dark chocolate.
One of the processes that takes away nutrients from the raw cocoa (or cacao) while it is being processed to make dark chocolate, is alkalization. Alkalized cocoa powder contains potassiumcarbonate, sodium carbonate, sodium hydroxide, or magnesium. These neutralize the acids of the chocolate and make the powder easier to dissolve into a liquid. An other thing commonly added to cocoa powder is corn starch to keep it from caking especially during storage.
The better dark chocolates do not add these fillers. A few other fillers include, waxes, dyes, vegetable oils, etc..
Where a lot of the nutrients that are naturally present in raw cacao beans get lost is in the heating process. If you can find cold processed chocolate that will have more nutrients in it. If you do testing on dark chocolates and compare regular heated dark chocolate and cold processed dark chocolate, you'll find that there are some flavanols and flavanoids in the cold processed chocolate that barely even register (if they do at all) in the heated chocolate. The key is to never heat the chocolate too high.
This is kind of common sense. We all know that there are less vitamins available in cooked vegetables than there are in raw vegetables. Just remember, chocolate is a vegetable. ;-), well, okay, at least it grows on trees! Technically it is a bean from a fruit.
Anyway for the finest health benefits, always pick cold processed or raw cocoa and non-alkalized dark chocolate.
