Medical Research Review
"Consumption of fish and n-3 Fatty Acids and Risk of Incident Alzheimer's Disease." -- Archives of Neurology. The study results indicate that participants who consumed fish once per week or more had 60% less risk of Alzheimer's disease, as compared to those who rarely or never ate fish.
My comment: I strongly advocate consumption of oily fishes and supplementation of high quality fish oil concentrate, and with excellent results. As our rivers and oceans are often very polluted (courtesy of extensive use of chemicals in agriculture), please, avoid consumption of fish that is known to contain a large amount of mercury, such as large tuna, swordfish, and sturgeon. You may obtain additional information from EPA website. The safest fishes are wild or clean water salmon, sardines, herring, small mackerell, and trout.
Dr. Radzik advises that you combine proper nutrition, active lifestyle, and other preventive measures with the appropriate medical care that only your physician can and will provide. Although prevention makes great difference, do not underestimate the benefits of early detection. Here, primary example is early detection of colon polyps and early stage of colon cancer. There are many other conditions that are easy to control with a proper nutritional and lifestyle modification program.