Testosterone is the hormone du jour … a hormone that can enhance sex life, boost mood and possibly protect against heart attacks. What’s not to like? Now, a growing body of evidence is suggesting that testosterone may even stave off Alzheimer’s disease or, in the case of those who already have symptoms, improve quality of life.
In a study published in 2010 in the Journal of Alzheimer’s Disease, researchers at the University of Hong Kong reported that higher levels of testosterone later in life protected against the development of Alzheimer’s. Closer to home, in 2004 researchers for the Baltimore Longitudinal Study of Aging, which followed 574 men ages 32 to 87 for an average of 19 years, reported that for every 10-unit increase in levels of testosterone, the risk of developing Alzheimer’s was lowered by 26 percent.
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Testosterone may also improve quality of life in men with mild Alzheimer’s disease, according to research published in the Archives of Neurology in 2006. In that study, researchers examined the effects of daily applications of testosterone gel to the skin of men with Alzheimer’s for six months. Another group of men was treated with a placebo gel. The researchers measured a range of functions including cognitive skills, verbal learning, psychiatric symptoms such as depression and anxiety, and quality of life. What they found was that Alzheimer’s patients who were treated with testosterone had a significantly better quality of life, as assessed by their caregivers, than patients treated with the placebo. However, improvement wasn’t evident in memory or other cognitive skills.
“Testosterone is the number one most effective agent to fight Alzheimer’s,” says Edward Friedman, Ph.D., author of The New Testosterone Treatment: How You and Your Doctor Can Fight Breast Cancer, Prostate Cancer and Alzheimer’s. “It lowers the production of beta amyloid and increases its degradation so the body breaks it down and gets rid of the excess.” That keeps beta amyloid, a plaque that causes much of the brain destruction associated with Alzheimer’s, from building up in the brain. Testosterone also improves blood flow to the brain as well as glucose metabolism, says Friedman. Impaired blood flow to the brain and the inability of the brain to metabolize sugar, or glucose, contribute to Alzheimer’s, he adds.
An estimated 5.2 million Americans, including 200,000 younger than age 65, have Alzheimer’s. So it’s no surprise that researchers are looking for ways to prevent the plaques and tangles in the brain that are the hallmark signs of Alzheimer’s. And it’s no surprise that many people are investigating testosterone as a solution. But whether the hormone is the answer so many people are looking for is still unclear, warns Heather Snyder, Ph.D., director of medical and scientific operations for the Alzheimer’s Association.
“We can’t draw conclusions based on relatively small studies,” Snyder says. “We know that as we age there are changes in hormone levels,” adds Snyder. “But Alzheimer’s is a very complex disease that is unlikely to be the result of one single factor.” Indeed, she says, the disease may well be caused by something that has not yet been identified.
“We do believe in exploring all the possibilities about what might be happening in the disease and the disease process and unlocking the mysteries,” says Snyder. In fact, the Alzheimer’s Association has funded research to investigate the link between testosterone and Alzheimer’s. One such study, done in 2006, reported that low levels of testosterone sped the development of an Alzheimer’s-like disease in mice; testosterone, on the other hand, stopped the decline. Mice with low levels of testosterone had higher levels of beta amyloid in their brain, whereas rodents that received testosterone had lower levels of the protein and were less likely to be cognitively impaired.
Before any recommendations can be made about preventing or treating Alzheimer’s with testosterone, more research must be done. And any promising results will need to be “replicated in diverse and larger populations,” adds Snyder.
What’s more, it must be clear that the benefits of such therapy clearly outweigh any potential risks. These include possible side effects such as sleep apnea; prostate cancer or benign prostate hyperplasia; liver problems, including tumors; congestive heart failure; and enlarged breasts.
So while the jury is still out as to whether testosterone will one day be the cure for Alzheimer’s, this new research most definitely offers a glimmer of hope in what can otherwise seem a hopeless diagnosis.