The study team found that greater adherence to the diet was linked with preserved microstructure in extensive areas of the white matter up to a decade later. And this appeared to be related to strong cognitive benefit, equal to up to 10 years of delayed cognitive aging for those with the greatest adherence.
“This is to our knowledge the first study investigating the associations of the Mediterranean diet to brain structure in humans, focusing not only on grey matter volume but also on white matter architecture (a more novel marker of brain health),” Cecilia Samieri, PhD, from University of Bordeaux, France, told Medscape Medical News.
“These findings give mechanistic clues on the link between the Mediterranean diet and lower cognitive aging which have been suggested in previous research,” she said.
The study was published online July 16 in Alzheimer’s & Dementia.
The Mediterranean diet has been associated with a lower risk for Alzheimer’s disease, but the underlying mechanisms were unclear.
The new findings are based on 146 non demented older adults in the Bordeaux Three-City study. Participants provided information on their diet, and underwent MRI an average of 9 years later.
“Our results suggest that the Mediterranean diet helps preserve the connections between neurons, which appear to be damaged with aging, vascular brain diseases and neurodegenerative diseases such as Alzheimer’s dementia,” said Dr. Samieri.
“In addition, the regions which appeared preserved with greater adherence to the Mediterranean diet were extended and were not specific to a particular disease, suggesting that the Mediterranean diet may have the potential to prevent not only stroke, but also multiple age-related brain pathologies, ” she added.
The added finding that none of the individual components of the diet was strongly associated with imaging results “supports our hypothesis that overall quality may be more important to preserve brain structure than any single food,” the researchers write.
Keith Fargo, PhD, director of scientific programs and outreach at the Alzheimer’s Association said these findings and conclusions are “sensible”. “One study can’t tell the whole story, but it is consistent with the idea that the Mediterranean diet may have some beneficial effect for your brain vasculature, which could account for some of the cognitive effects some studies are seeing.”
Dr. Fargo said it’s important to note that the study was small and diet was assessed only at one point and brain structure measured 9 years later. “Whether patients maintained the Mediterranean diet over time is unknown,” he said.
“This is an observational study not an interventional study, which is ultimately needed to determine whether there really is an effect. There may be something else about people that makes them both more likely to eat a Mediterranean diet and more likely to have preserved white matter structure as they age,” he said.
However, he said the findings support a growing literature indicating that diet does matter to brain health.
medscape.com August 7, 2015