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 β-amyloid load via C-Pittsburgh compound B [PiB] PET and neurodegeneration via F-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 ( < 0.001). Longitudinally, the MeDi--group showed CMRglc declines and PiB increases in these regions, which were greater than those in the MeDi+ group ( < 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.