The study, published in the journal Neuropsychiatric Disease and Treatment, said cocoa flavanols -- the unique compounds found naturally in cocoa -- may increase blood flow to the brain.

Harvard medical scientists said researchers suggest long-term improvements in brain blood flow could impact cognitive behavior, offering potential defense against debilitating brain conditions including dementia and stroke.

When the flow of blood to the brain slows over time, the result may be structural damage and dementia. Scientists speculate that maintaining an increased blood flow to the brain could slow this cognitive decline.

The study participants who regularly drank a cocoa flavanol-rich beverage made using the Mars Inc. Cocoapr process had an 8 percent increase in brain blood flow after one week, and 10 percent increase after two weeks.