Eat oily fish to boost brain power

http://www.bbcgoodfood.com/howto/guide/10-foods-boost-your-brainpower

Essential fatty acids (EFAs) cannot be made by the body and must be obtained through diet. The most effective omega-3 fats occur naturally in oily fish as EPA and DHA. Good sources include linseed (flaxseed) oil, soya bean oil, pumpkin seeds, walnut oil and soya beans. They are good for healthy brain function, the heart, joints and general wellbeing. 

Oily fish contains EPA and DHA in a ready-made form, which enables the body to use it easily. The main sources of oily fish include salmon, trout, mackerel, herring, sardines, pilchards and kippers. Low DHA levels have been linked to a higher risk of developing Alzheimer's disease and memory loss.