For years, the news about Alzheimer's and other dementia-related illness has been unrelentingly grim. We don't know many of the causes. We don't have a cure.
Researchers warned that the number of people with brain-robbing diseases would double in the next three decades as the baby boom generation aged. In other words, if you lived long enough, you'd likely suffer from it.
Finally, however, good news: Dementia rates in England and Wales plunged by 25 percent over the past two decades, according to a recent study in The Lancet. Another recent study, from Denmark, found that people in their 90s now are mentally sharper than those who reached that age a decade ago. Researchers suspect, but can't say for certain, that such trends are also afoot in the United States.
Tentative conclusion: That slide into dementia and Alzheimer's with age may not be inevitable. New theory: Eating right, exercising and cutting out smoking is not only good for your heart and lungs ... it may also help forestall dementia.
Dr. Marsel Mesulam, director of the Cognitive Neurology and Alzheimer's Disease Center at Northwestern University, told us these studies are "very exciting. The field had become pretty depressing with the news that the older you get, the more you lose cognition to the point where this could become almost inevitable if you live long enough."
Here's what anyone bent on preserving his or her gray matter into advanced age needs to know: What you eat, how well you take care of your health, how much you exercise, could well make a difference.
Researchers say those who keep their blood pressure and cholesterol under control are likely to fare better, possibly because they avoid dementia that is caused by ministrokes and other vascular damage.
Education, too, is associated with lower dementia rates. Those with more education tend to fare better than those with less. (Another good reason to finish high school and go to college.) You don't need a Ph.D, says Dr. Dallas Anderson of the National Institute on Aging. But being better educated may guide choices you make over a lifetime that help shield you from dementia.
Make no mistake: Your lifestyle choices matter, and not just for dementia. Researchers reported last year in the New England Journal of Medicine on the impact of high cholesterol, blood pressure, smoking and diabetes on life expectancy. If you don't have any of those factors, your risk of dying of cardiovascular disease is amazingly low: 4.7 percent for men and 6.4 percent for women. But if you have at least two of those factors, you have a much higher risk of heart disease or stroke.
Researchers have theorized that keeping the brain active - via crossword puzzles, for instance - would help prevent a mental slide. Some suggested brisk exercise or staying socially engaged helps. Diet? Vitamins? Drugs? So far, there's no strong evidence that any of these prevent dementia.
Many baby boomers are terrified that their memories are slipping. If you've ever walked into a room and forgotten why, you know. If you've ever encountered a colleague on the elevator and blanked on his name, you know. If you've ever forgotten the end of a sentence while you were writing it ...
A sobering story in The New York Times says that some people can detect their slide into early memory loss and dementia before doctors see symptoms or medical tests can detect anything amiss.
Before you panic, please remember our larger point: Following this health advice isn't a guarantee that you'll be sharp into your 90s. But those who shrug about these things and say, 'it's out of my hands,' are wrong. The choices you make add healthy weeks, months or years of life, or chip away at them.
"Once the brain goes downhill, it is hard to bring it back," Anderson told us. Hard to forget that.