From Alzheimer’s Association

According to the most current research, a brain-healthy diet is one that reduces the risk of heart disease and diabetes, encourages good blood flow to the brain, and is low in fat and cholesterol. Like the heart, the brain needs the right balance of nutrients, including protein and sugar, to function well. A brain-healthy diet is most effective when combined with physical and mental activity and social interaction.

More under the link below,

http://www.alz.org/we_can_help_adopt_a_brain_healthy_diet.asp