Preventive Maintenance For the Brain
Tuesday, February 21, 2006
If it seems you're forgetting more as you grow older, you are. Like most other organs in the body, the brain gets smaller as we age, leading to a decline in memory, decision-making ability and verbal skills. That doesn't necessarily mean that you're on a steep downhill slide toward certain dementia, say experts. Growing evidence suggests there are steps you can take to better the odds of preserving your brainpower and protecting it against disease.
Two avenues for boosting cognition -- challenging your brain and exercising your body -- have drawn considerable scientific research.
Just last week a massive review of the scientific data, published online, found that getting lots of physical activity and reducing your risk of heart disease -- by cutting cholesterol and blood pressure levels, for example, or losing weight -- are among the best ways to maintain a healthy brain. The study, funded by the National Institutes of Health (NIH), also found that increased mental activity throughout life appears to preserve brainpower.
Through its "Maintain Your Brain" campaign, the Alzheimer's Association urges people to regularly engage in mentally stimulating activities. These may involve doing logic puzzles like Sudoku, reading an entire newspaper daily or going to a museum -- anything that takes you outside your normal range of thinking, said Elizabeth Edgerly, a clinical psychologist who helped develop the campaign.
Mental challenges such as these, researchers theorize, build neural pathways in the brain, buffering against age-related loss and possibly an assault by disease. Some researchers have hypothesized that persistent, effortful mental activity might even retard underlying disease.
Meanwhile, evidence that physical activity may protect against cognitive loss impresses other experts on aging. A recent study that followed more than 1,700 normal seniors for six years found those who exercised the most -- at least three times a week -- were least likely to develop Alzheimer's disease. One theory, based partly on animal research, is that physical exercise may improve blood flow and oxygen delivery to the brain and increase substances that promote the growth of tissue and blood cells in the hippocampus, a region critical to memory.
But even if mind games or physical activity confer a protective benefit -- scientists say proof is still far off -- there are limits: The most determined personal efforts won't override a strong genetic predisposition to Alzheimer's, say experts. (But not every mental lapse is a sign of dementia. See "Is It Normal? Or a Warning Sign?")
Other factors may also affect brain integrity, including diet (for brain health, nutritionists suggest a diet low in saturated fats and rich in vegetables, fruit and fish with omega-3 fatty acids), social life (an active one is thought to improve immunity and reduce inflammation, believed to play a role in Alzheimer's) and health problems like diabetes and heart disease.
Those issues aside, a major question remains: If exercise is protective, what kind is best and at what dose? No one can say.
"You can say with conviction that if a person decides to exercise a certain amount every day or week, that it will help their heart and that it might help their head," said Marcelle Morrison-Bogorad, director of the neuroscience and neuropsychology of aging program at the National Institute on Aging (NIA). But whether one form of exercise is superior-- whether, say, aerobic exercise beats non-aerobic -- isn't yet known, any more than whether playing chess or listening to classical music will give you more protection than playing Scrabble or going to a rock concert.
The idea that challenging the brain may help stave off dementia has intrigued many researchers. Defining what constitutes "challenging," though, is difficult, said Edgerly. "If you think of each of us as individuals, what's mentally stimulating to me might be really easy for you and not make you break a cognitive sweat," she said.
The Religious Orders Study, which began in 1993 and includes more than 1,000 nuns, priests and brothers across the country, has found that those who engage more often in reading, puzzles and processing information have a 47 percent lower risk of Alzheimer's disease than those who do little or none. The NIA is funding the study.