Some tips on slowing down the effects of aging on the brain:

Physical exercise: Being active can make us more cognitively healthy, says Dr. Ronald C. Petersen of the Mayo Clinic.

Diet: Eating more fresh fish, fruit and vegetables makes us physically and perhaps mentally healthier.

Moderate drinking: Leah Hanson, director of HealthPartner's Alzheimer's Research Center, calls it "protective, in general," but notes that heavy drinking can affect memory.

Mental exercises: Neuropsychologist Susan McPherson touts Sudoku, Scrabble, Battleship and other "games in which you have to think," while Petersen is not sold on their benefits. Hanson is in the middle: "We don't have proof that it will solve the problem, but it is good practice."

Active social life: People with strong connections to family and friends tend to stay sharper, Hanson says. Adds McPherson: "There's a lot of cognitive activity going on in socializing. Even if you're talking about what your grandchildren are doing, you're pulling information from different sources to formulate ideas and have discussion."

Lifelong learning: It takes fifty-somethings more time to pick up a language or memorize something than those who are in their college years. But that doesn't mean that they shouldn't try, McPherson says.