Effects of acute, sub-chronic and chronic chocolate consumption with different percent of cocoa/sugar on memory and EEG waves in rats

People mainly have a major interest in eating some palatable foods such as chocolate and sweet foods that influence brain functions. This study investigated the effects of acute, sub-chronic and chronic chocolate consumption with different percent of cocoa/sugar on learning, memory, memory consolidation and electroencephalogram (EEG) waves in rats.

Thirty-five male Wistar rats were allocated to five main groups containing control and sucrose as well as dark, milk and white chocolate groups. All groups were freely fed with chow, different kinds of chocolate and sucrose separately for 1,7 and 14 days as acute, sub-chronic and chronic food consumption. Also, memory and memory consolidation were evaluated using a passive avoidance test on days 1,7 and 14. In addition, brain electrical activity was evaluated by EEG.

Acute and sub-chronic dark and milk chocolate consumption significantly improved latency after day 1 and particularly day 7. In addition, only the chronic dark chocolate diet showed a significant enhancement in latency after 14 days. White chocolate and sucrose diets did not have significant effects on three latencies. The milk and dark chocolate diets changed nearly all brain waves of EEG, while the sucrose diet did not affect any of them.

Unlike sucrose and white chocolate, dark chocolate (acute, sub-chronic and chronic consumption) and milk chocolates (acute and sub-chronic consumption) had beneficial effects on memory and nearly all electrical brain activity probably due to high levels of cocoa and perhaps its antioxidant effect. Hence, these types of diets modified brain homeostasis and increased conscious state and relaxation reduction.