Dark Chocolate Benefits Eyesight, Brain Health

READING, United KingdomEating dark chocolate, which contains high levels of cocoa flavonols, may boost eyesight and brain health by improving blood flow to the retina and brain, according to a study published in the journal in Physiology and Behavior. The findings suggest the effects may last for several hours after consumption.

Researchers at the University of Reading conducted a randomized, single-blinded, order-counterbalanced, crossover design in which 30 healthy adults ate both dark chocolate containing 720 mg of cocoa flavanols and a matched quantity of white chocolate, with a one week interval between testing sessions. Visual contrast sensitivity was assessed by reading numbers that became progressively more similar in luminance to their background. Motion sensitivity was assessed by measuring the threshold proportion of coherently moving signal dots that could be detected against a background of random motion, and by determining the minimum time required to detect motion direction in a display containing a high proportion of coherent motion. Cognitive performance was assessed using a visual spatial working memory for location task and a choice reaction time task designed to engage processes of sustained attention and inhibition.

They found relative to the control condition, cocoa flavanols improved visual contrast sensitivity and reduced the time required to detect motion direction, but had no statistically reliable effect on the minimum proportion of coherent motion that could be detected. In terms of cognitive performance, cocoa flavanols improved spatial memory and performance on some aspects of the choice reaction time task.