From The New York Times:
Behind all the good-natured joking about “senior moments” lies real frustration and fear. How empowering, then, that we can do something to ward off normal, age-related memory loss: exercise. No, it’s not as easy as popping a pill. But as Sue Halpern reports in “Can’t Remember What I Forgot,” even a few brisk walks per week can have a measurable effect. Exercise promotes the birth of new neurons in the very part of the hippocampus (a brain structure crucial to forming new memories) that begins to malfunction with age. Exercise also counters age-related shrinking of the prefrontal cortex, an area involved in concentration and working memory (as in remembering a phone number long enough to dial).
Of course, if you’re unwilling to exercise for your health, or even to look good in a bathing suit, perhaps you’re still hoping for an easier solution. The problem, Halpern explains, is that solid, peer-reviewed science has not yet proved that anything else works: not herbal supplements, fish oil, vitamin E, almonds, $400 interactive computer software or even crossword puzzles. (After reading her section on blueberries, however, you’ll want to buy them by the bucketful.)