Researchers meeting in the United States say there isn't yet enough evidence to support the idea that dementia and Alzheimer's disease are preventable -- but they're holding out hope that an active lifestyle might help.
The independent panel, convened in Washington by the National Institutes of Health, reviewed the existing research on purported dementia prevention measures, such as mental stimulation, dietary supplements and medications.
Their conclusion? There is no evidence such strategies effectively delay or reduce the severity of Alzheimer's and dementia.
"We wish we could tell people that taking a pill or doing a puzzle every day would prevent this terrible disease, but current evidence doesn't support this," Dr. Martha L. Daviglus, a professor at Northwestern University, said in a statement.
Dr. Neil Buckholtz, with the U.S. National Institute on Aging, was similarly cautious.
"At this point, there is not a high level of evidence that any of these factors can prevent Alzheimer's or age-related cognitive decline," he said.
The panel concluded that there are no special foods, vitamins, or medications that can prevent dementia or cognitive decline, though there are medications that can slow the progression of Alzheimer's in those already diagnosed.
Still, they say, some of these supplements and diets are not necessarily harmful and may confer other benefits. And the panel didn't rule out the possibility that further carefully-designed randomized studies might still show that diet or supplements could reduce dementia risk.
Research has shown that diabetes, depression and smoking are related to Alzheimer's disease and dementia. But the research has so far fallen short of concluding that one causes the other, the experts noted.
"These associations are examples of the classic chicken or the egg quandary. Are people able to stay mentally sharp over time because they are physically active and socially engaged or are they simply more likely to stay physically active and socially engaged because they are mentally sharp?" said Dr. Daviglus.
On a hopeful note, the experts said that unfinished studies on physical activity, omega-3 fatty acids, anti-hypertensive medications and cognitive stimulation could supply new insights on how to prevent the two diseases.
Researchers are now following elderly participants, in the hopes of validating whether activities such as volunteering can prevent dementia.
"What we are predicting is that the more demanding the activities, the more protective they'll be," said Nicole Anderson, a neuropsychologist at Baycrest Centre for Geriatric Care in Toronto.
Evelyn (Burns) Weinrib is 76, and volunteers at Toronto's Baycrest Home Care Services nursing home. During breaks, she knits -- and she believes are active lifestyle is keeping her brain young.
"When you are volunteering, you are challenged. It helps your mind grow," she told CTV News.
An estimated six million North Americans suffer from Alzheimer's. Millions more have a mild form of dementia. Those numbers are expected to rise as the baby-boom generation ages.
With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip
