Maybe in some way this may sound unexpected or even strange, but for me the best food for the brain is any kind of mental job which maintains the neurophysiological activity of the brain. Resent research confirm that regular mental excersises can prevent or slow down the progression of Alzheimer's disease and other types of demetia. For instance, activities such as solving puzles or playing chess, reading or, especially, learning foreign lenguages showed a good mental health effect. I think good and sufficient sleep, as well as a diet based on complex carbs and foods rich in vitamins and Omega-3 also make a difference. However, I would say that intense cerebral activity is one of the main sources of brain efficiency. #helpmecorrect Let me know if you have any questions about the corrections :)