Antioxidants protect your brain from forming free radicals, or unstable atoms in your brain. Loading up on foods with naturally occurring antioxidants will help prevent these from forming. Green vegetables like broccoli, brussels sprouts, and spinach as well as other dark skinned fruits like grapes, cherries, blueberries, raspberries, and cranberries are all great sources of natural antioxidants that will help keep from incurring cell damage from free radicals.
Cold water fish like tuna, salmon, and mackerel are very high in omega-3 fatty acids that stimulate cell regeneration and blood circulation, though the largest benefit are to the health of your brain. A study was published in the April 2007 Journal of Neruoscience that involved feeding laboratory mice different diets to study their effects on the brain. A group that was supplemented with omega-3 fatty acids showed a significantly lower level of abnormal protein buildup in the brain after 3 months. These abnormal proteins are thought to contribute to memory loss over time.
In 2006, a study at Columbia University showed that a group of the elderly who ate a diet that closely resembled the Mediterranean diet had a much lower risk of developing cognitive decline that can lead to Alzheimers. A key factor to this is eating only 12-14 ounces of red meat per week, along with higher amounts of fruits and vegetables while using olive oil as the main source of fat.
The same 2006 study also showed that moderate amounts of exercise were very beneficial in keeping body and mind in top form. Even just 4 hours of light physical activity per week can be protective against Alzheimers. Dont stop at exercising your body though, an active mind is the most powerful weapon in your arsenal. Reading often will help with any vocabulary related decline, but even doing simple things like crossword puzzles will keep you on your toes.