Every day, it seems, a new study reports that caffeine — or fish oil or friendships — lowers the risk of Alzheimer's disease.

Many of these are "associations" that may or may not have a cause-and-effect relationship. There is still much that isn't known about the telltale plaques and tangles that slowly strangle the brains of Alzheimer's victims.

But what scientists do know now that they didn't just a decade ago is that people generate new brain cells, and new connections between them, throughout life. And the more mental reserves people build up, experts believe, the better they can stave off age-related cognitive decline.

Click here to read the full story from the Wall Street Journal.