Successful Aging: How can I prevent Alzheimer’s disease?

Q. I recently returned from visiting a friend who is in the memory care section of an assisted living facility. He has Alzheimer’s disease. I was depressed seeing my friend so immobile and unable to communicate as well as seeing others in a room with a television no one was watching. What can I do to protect myself from such an existence? Many thanks. S.B.
Dear S.B.
You have asked a question that is challenging the greatest minds in the country, and perhaps the world. To date, scientists d