Through some basic research I have found that the hallmarks of Alzheimers are believed to be plaques and tangles. What these do is they attack nerve cells and take away function from the brain. A treatment has yet to be found for this disease that touches many families and is carried genetically.
"Evidence is also mounting for the promotion of exercise and a healthy diet to reduce Alzheimer's risk. Avoiding tobacco, limiting alcohol consumption, staying socially active, and engaging in intellectually stimulating activities have also been shown to have a protective effect against Alzheimer's disease." http://alzheimers.about.com/od/whatisalzheimer1/a/causes.htm
The information listed above gives some of the examples physicians give to help those susceptible to the disease fight it off.
Although I may not know much about the true science behind this disease I have seen it in work. My grandmother was diagnosed with Alzheimer's in her 60s and lived well into her 80s with the disease. What began as forgetting she had just said something turned into repetitive thoughts, although always kind, forgetting where she was headed when she got into her vehicle, not knowing how many drinks she had consumed, and even to a point where names of her own family were at a loss at times. The disease brought memories of the past to her at times and for her it was typically Christmas in July. It is a wicked disease that takes away a person's quality of life by making them believe they are somewhere other than where they are and make them forget their own thoughts as soon as they have been spoken.
One painful memory for my family was when my grandmother was in hospis care. She was asking my mother, one of four sisters, when her husband would be coming to see her. Caught up in emotion one of the sisters answered, "Mom, dad passed on ten years ago. He is not coming." If this would have been good news, which is what they eventually resorted to saying, "He'll be here soon. Dad is just tied up at work!" for some reason the bad memories lingered longer.
As I said it is a wicked disease and what frightens me most is that it is said to skip a generation, which means my brothers and I are possibly going to be diagnosed one day.