Could a Mediterranean Diet Reduce Brain Shrinkage in Old Age?

Greater adherence to a Mediterranean-type diet is associated with less brain volume loss over a 3-year period in older age, according to a new study.

“It might be that the diet protects the brain from shrinkage and this could result in better maintenance of cognitive functions as we age,” said study lead author Michelle Luciano, PhD, from the Center for Cognitive Aging and Cognitive Epidemiology at the University of Edinburgh in Scotland.
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The researchers assessed the association between Mediterranean-type diet and change in brain MRI volumetric measures and mean cortical thickness across a 3-year period in older age (73-76 years). They focused on 2 longitudinal brain volumes (total and gray matter; n=401 and 398, respectively) plus a longitudinal measurement of cortical thickness (n=323), for which the previous cross-sectional evidence of an association with the Mediterranean diet was strongest. The investigators calculated adherence to the Mediterranean diet from data gathered from a food frequency questionnaire at age 70, 3 years prior to the baseline imaging data collection.

In regression models adjusting for relevant demographic and physical health indicators, the researchers found lower adherence to the Mediterranean diet to be associated with greater 3-year reduction in total brain volume (explaining 0.5% of variance, p<0.05). This effect was half the size of the largest covariate effect (i.e., age). Cross-sectional associations between Mediterranean diet and baseline MRI measures in 562 participants were not significant. Targeted analyses of meat and fish consumption did not replicate previous associations with total brain volume or total gray matter volume.

In one main study limitation, the investigators only had a single measurement of diet so they do not know how long people had been adhering to it, Dr Luciano said. However, they have recently collected more dietary information from the study participants so they can check the stability of their diet over time.

“Our research adds to the growing literature that a Mediterranean diet is associated with many positive health outcomes, but further research is needed to confirm whether any late-life change in diet would produce such effects and whether the association is indeed causal,” Dr Luciano said.

They aim to study the effect of adherence to a Mediterranean diet on change in cognitive functions in old age and whether these associations can be explained by the change in brain volume.

—Mike Bederka

Reference:

Luciano M, Corley J, Cox S, et al. Mediterranean-type diet and brain structural change from 73 to 76 years in a Scottish cohort [published online Jan. 4, 2017]. Neurology. doi:http://dx.doi.org/10.1212/WNL.0000000000003559