Mediterranean diet and 3-year Alzheimer brain biomarker changes in middle-aged adults

Objective To examine in a 3-year brain imaging study the effects of higher vs lower adherence to a Mediterranean-style diet (MeDi) on Alzheimer disease (AD) biomarker changes (brain beta-amyloid load via C-11-Pittsburgh compound B [PiB] PET and neurodegeneration via F-18-fluorodeoxyglucose [FDG] PET and structural MRI) in midlife. Methods Seventy 30- to 60-year-old cognitively normal participants with clinical, neuropsychological, and dietary examinations and imaging biomarkers at least 2 years apart were examined. These included 34 participants with higher (MeDi+) and 36 with lower (MeDi-) MeDi adherence. Statistical parametric mapping and volumes of interest were used to compare AD biomarkers between groups at cross section and longitudinally. Results MeDi groups were comparable for clinical and neuropsychological measures. At baseline, compared to the MeDi+ group, the MeDi-group showed reduced FDG-PET glucose metabolism (CMRglc) and higher PiB-PET deposition in AD-affected regions (p < 0.001). Longitudinally, the MeDi-group showed CMRglc declines and PiB increases in these regions, which were greater than those in the MeDi+ group (p(interaction) < 0.001). No effects were observed on MRI. Higher MeDi adherence was estimated to provide 1.5 to 3.5 years of protection against AD. Conclusion Lower MeDi adherence was associated with progressive AD biomarker abnormalities in middle-aged adults. These data support further investigation of dietary interventions for protection against brain aging and AD.