Mediterranean diet and preserved brain structural connectivity in older subjects.

Introduction: The Mediterranean diet (MeDi) has been related to a lower risk of Alzheimer's disease; yet, the underlying mechanisms are unknown. We hypothesized that protection against neurodegeneration would translate into higher gray matter volumes, whereas a specific association with preserved white matter microstructure would suggest alternative mechanisms (e.g., vascular pathways).

Methods: We included 146 participants from the Bordeaux Three-City study nondemented when they completed a dietary questionnaire and who underwent a 3-T magnetic resonance imaging at an average of 9 years later, including diffusion tensor imaging.

Results: In multivariate voxel-by-voxel analyses, adherence to the MeDi was significantly associated with preserved white matter microstructure in extensive areas, a gain in structural connectivity that was related to strong cognitive benefits. In contrast, we found no relation with gray matter volumes.

Discussion: The MeDi appears to benefit brain health through preservation of structural connectivity. Potential mediation by a favorable impact on brain vasculature deserves further research.