Here's more research that a heart healthy diet is also good for the brain. According to a recent study published online on May 18, 2012 in the Annals of Neurology, eating "good" fats was associated with less cognitive decline over a four-year period.
This study involved 6,183 women over the age of 65 who were evaluated over a four-year time frame. They reported their diet to researchers and were tested several times throughout the study to assess their cognitive functioning.
Participants whose diet consisted of more monounsaturated fat (or "good" fat), such as olive oil, nuts or seeds, showed better memory and overall cognitive functioning over four years than those whose diets contained more "bad" fat, such as the saturated fat contained in butter, cheese and red meats. The women who ate more "bad" fat demonstrated a bigger cognitive decline throughout the study.
Research consistently has demonstrated that eating right, exercising, and staying mentally active can reduce the risk to develop Alzheimer's or another dementia. So, while scientists continue to work on isolating the causes of Alzheimer's, knowing how to reduce the risk plays a key role in the fight against Alzheimer's.
Also, here's more research on diet and its effect on cognitive functioning.

Coconut oil is the ultimate oil. Dont be afraid of saturated oils. They were not all made equal.
I agree with Stanley. Coconut Oil has proven to be very helpful in cases of dementia and Alzheimer’s and has brought some victims of the disease back to their families. Why not try it?
I have been using coconut oil in cooking for my mother, and her cognitive function has gotten better. Proof enough to me.
In April of 2003, a scientific study indicated that there may be a connection between Alzheimer’s and Parkinson’s disease. In that study, it was concluded that older adults who develop the tremors and other classical symptoms of Parkinson’s disease may be up to eight times as likely to develop Alzheimer’s disease as well.
Is there a connection between Alzheimer’s and Parkinson’s disease? More and more studies indicate that they’re might be a link between these two debilitating diseases. Only more time, and more research will be able to explain the connection between Alzheimer’s and Parkinson’s disease.
Consumption of dairy products, especially milk, increases a man’s risk of contracting Parkinson’s disease, according to a recent study published in the American Journal of Epidemiology.
Previous studies have established a link between Parkinson’s — a degenerative central nervous system disorder that commonly causes the impairment of motor skills, including speech — and the consumption of dairy. It is understood that allergies to dairy deplete the immune system of vitamin C and Zinc. Zinc is an essential trace mineral that is a component of over 200 enzymes, and functions as part of more enzymatic reactions than any other mineral. Zinc is readily absorbed in the upper small intestine. The body only absorbs the amount that it needs and discards the rest through the feces. However, zinc is stored in the liver, pancreas, kidney, bones, and voluntary muscles, parts of the eyes, glands, sperm, skin, hair, and fingernails. However, because the small intestine only absorbs what is needed at the time, it is important that zinc be constantly replaced. Zinc is probably most famous for being an immune system booster. When zinc levels decrease, the number of T cells decreases, thymic hormone levels decrease, and many white blood cell functions cease. Both Zinc and Vitamin C have antiviral activity, especially against several of the viruses that cause the common cold.