MONDAY, April 22, 2002 (HealthDayNews) -- A new study of the brain power of elderly men adds ammunition to the theory that testosterone has a lot to do with the mind's ability to work properly in old age.
However, don't ask your doctor for a testosterone supplement just yet; researchers aren't sure if a pill will have any effect at all.
"Our study only looked at natural testosterone levels, and so it doesn't prove that testosterone supplements can prevent cognitive decline," study author Dr. Kristine Yaffe says in a statement.
Yaffe, an assistant professor of psychiatry at the University of California at San Francisco, examined a study of aging among 300 men from the Pittsburgh area. The average age of the men was 73. Among other things, the researchers tested the mental skills of the men in areas of concentration, memory, attention and language.
People at risk for brain disorders like Alzheimer's disease tend to score lower on such tests.
The findings appear in the April issue of the Journal of the American Geriatrics Society.
Yaffe found men scored higher on the tests if they had higher levels of a type of testosterone that affects the brain. The levels of estrogen -- a hormone that appears in both men and women -- appeared to have no effect.
Testosterone has a variety of effects on the body, says John Seibel, an endocrinologist who works in private practice.
Testosterone "builds muscle mass, and it helps change fat into protein or muscle," he says. Also, men with low levels of testosterone who take supplements generally have "a better sense of well-being and feel better. "
The boost in well-being may explain why men with higher testosterone levels score better on cognitive tests, Seibel says. People who feel better, he explains, also think better: "We know if we're stressed or depressed, we do much worse on many mental status exams."
However, it's not clear what's really going on because scientists have a limited understanding of how hormones affect the brain, Seibel says.
Testosterone, like estrogen, may stimulate specialized cells in the brain and limbic system, says Dr. James Grisolia, a neurologist at Scripps Mercy Hospital in San Diego.
It's too early to tell if testosterone can protect the aging brain from deterioration, Grisolia says. Some early studies indicated that estrogen appeared to protect women against Alzheimer's disease, but later research suggested the opposite. Long-term studies now underway should resolve the issue, he adds.
For now, men should avoid the hype about the effects of testosterone supplements, Seibel says.
"It frequently gets abused by people who say you need high testosterone to be 'young,'" he says.
However, testosterone supplements are appropriate for men whose hormone levels are unnaturally low, Seibel says. The problem is that many of the symptoms of low testosterone levels -- such as low libido, impotence and loss of muscle mass -- can be a sign of nothing other than normal aging.
What To Do
To learn more about the symptoms of Alzheimer's disease, visit the Alzheimer's Association. Meanwhile, the National Institute on Aging has a list of clinical trials testing a variety of treatment approaches.
Learn more about testosterone therapy from the Digital Urology Journal.
