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

TLDR

The study examined whether higher versus lower adherence to a Mediterranean‑style diet over three years influences Alzheimer disease biomarkers—amyloid deposition and neurodegeneration—in cognitively normal adults aged 30–60. Researchers recruited 70 cognitively normal adults (30–60 y) split into high‑ and low‑MeDi adherence groups and compared amyloid PET, FDG PET, and MRI biomarkers using statistical parametric mapping and region‑of‑interest analyses at baseline and follow‑up. Participants with lower MeDi adherence had higher amyloid deposition and lower glucose metabolism at baseline and, over three years, experienced greater amyloid increases and glucose metabolism declines than the high‑MeDi group, while MRI measures were unchanged; the high‑MeDi trajectory suggested 1.5–3.5 years of protection against Alzheimer disease.

Abstract

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 11C-Pittsburgh compound B [PiB] PET and neurodegeneration via 18F-fluorodeoxyglucose [FDG] PET and structural MRI) in midlife.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.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 (pinteraction < 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.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.