Karstens AJ, et al. - In a cohort of nondemented, nondepressed community-dwelling older adults (n = 82; aged around 68.8 years; 50% female, 50% minority), researchers assessed cross-sectional links between the Mediterranean diet (MedDiet) and cognitive and neuroimaging phenotypes related to Alzheimer disease (AD) and vascular dementia (VaD) separately. They performed dietary and neuropsychological assessments and neuroimaging and divided participants into High and Low (median split) MedDiet adherence groups. They examined cognitive phenotypes mainly related to AD (ie, learning and memory [L&M]) and VaD (ie, information processing and executive functioning). Hippocampal and dentate gyrus volumes quantified using T1-weighted images and the FreeSurfer 6.0 segmentation pipeline were included in AD neuroimaging phenotypes, and total white matter hyperintensity (WMH) volumes quantified using combined T1-weighted and T2-fluid-attenuated inversion recovery images were included in the VaD neuroimaging phenotype. Findings revealed better L&M performance and larger dentate gyri reported in the High MedDiet group vs the Low MedDiet group. There was no association of MedDiet adherence with information processing, executive functioning, or WMH. Overall, a link between increasing MedDiet adherence and specific cognitive and neuroimaging phenotypes was observed. When altered, these phenotypes were found to be related to AD.