Recent quotes:

Dark chocolate consumption reduces stress and inflammation: Data represent first human trials examining the impact of dark chocolate consumption on cognition and other brain functions -- ScienceDaily

"This is the first time that we have looked at the impact of large amounts of cacao in doses as small as a regular-sized chocolate bar in humans over short or long periods of time, and are encouraged by the findings. These studies show us that the higher the concentration of cacao, the more positive the impact on cognition, memory, mood, immunity and other beneficial effects."