At this time, there is no known way to prevent Alzheimer's disease. But there are things that may make it less likely.
Adults who are physically active may be less likely than adults who aren't physically active to get Alzheimer's disease or another type of dementia. Moderate activity is safe for most people, but it's always a good idea to talk to your doctor before starting an exercise program.
Older adults who stay mentally active may be at lower risk for Alzheimer's disease. Reading, playing cards and other games, working crossword puzzles, and even watching television or listening to the radio may help them avoid symptoms of the disease. So can going out and remaining as socially active as possible. Although this "use it or lose it" approach hasn't been proved, no harm can come from regularly putting the brain to work.
People who eat more fruits and vegetables, high-fiber foods, fish, and omega-3 rich oils (sometimes known as the Mediterranean diet) and who eat less red meat and dairy may have some protection against dementia.