A recent report by a panel of experts from the US National Institutes of Health has cast some doubt on the usefulness of a healthy diet, crossword puzzles and regular exercise in terms of delaying or reducing the severity of Alzheimer’s disease.

As the CBC reported, the panel expressed their doubt thus:

“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,” said Dr. Martha Daviglus, conference panel chair and professor of preventive medicine and medicine at Northwestern University in Chicago. The panel, however, said the public needs to understand such strategies are at best only loosely associated with an improved outcome. The cause-and-effect relationship, if any, is unclear, Daviglus said.

CAKEns contacted Dr. Kenneth Rockwood, a leading researcher into dementia who currently holds the Kathryn Allen Weldon Chair in Alzheimer’s research at Dalhousie University here in Nova Scotia, for comment on this.  His response:

There is a problem with these sorts of recommendations, which rely on “the evidence”.  The evidence is biased towards pharmacological interventions, which outnumber non-pharmacological interventions by hundreds to one.  So if the experts want to wait until there are multi-hundred person randomized controlled trials before daring to recommend exercise as a useful strategy in AD, we will wait a long time.  More valuable, it seems to me, are data from cohort studies, in which people who exercise and have AD can be compared against those who do not exercise, and have AD.  Although the design of a study like this means that we can never know for sure if exercise would work in people who take it up because they have AD, the data do allow some insight. (There are also elaborate reasons why we cannot know for sure from a randomized trial if the patient in front of us will benefit either, but that is another matter.)

Our analysis of data from the Canadian Study of Health and Aging suggests that there are cognitive benefits to exercise, even in people with dementia.  The open access reference for this work is: Middleton LE, Mitnitski A, Fallah N, Kirkland SA, Rockwood K.Changes in cognition and mortality in relation to exercise in late life: a population based study. PLoS One. 2008 Sep 1;3(9):e3124.

You can read the full report form the National Institutes of Health panel here.