New Study Questions Whether Healthy Diet Reduces Dementia Risk

A number of studies find that diet may lower risk of dementia in an individual. A new study from Sweden, however, failed to find a correlation between reduced dementia risk based on healthy diet. At the end of study, 6.9% (n=1,943) of participants who had a Mediterranean diet were diagnosed with dementia, including Alzheimer disease (AD) and vascular dementia.

“Previous studies on the effects of diet on dementia risk have had mixed results,” said study author Isabelle Glans, MD, of Lund University in Sweden. “While our study does not rule out a possible association between diet and dementia, we did not find a link in our study, which had a long follow-up period, included younger participants than some other studies and did not require people to remember what foods they had eaten regularly years before.”
 
For the study, 28,000 individuals from Sweden with an average age of 58 who did not have dementia at the start of the study were enrolled and followed over a 20-year period. Participants filled out a weekly food diary, a detailed food frequency questionnaire, and completed an interview during the study. 

Nils Peters, MD, of the University of Basel in Switzerland, who wrote an editorial accompanying the study, said, “Diet on its own may not have a strong enough effect on memory and thinking, but is likely one factor among others that influence the course of cognitive function. Dietary strategies will still potentially be needed along with other measures to control risk factors.”
 
Limitations of the study include participants possibly misreporting their dietary and lifestyle habits and that the study was done only among Swedes, which could introduce cultural biases, including typical dietary intake.