This study investigates the association between adherence to the Mediterranean diet (MeDi) and the risk of Alzheimer's disease (AD). The research involved 2,258 community-based nondemented individuals in New York, who were prospectively evaluated every 1.5 years. Higher adherence to the MeDi was associated with a lower risk of AD, with a hazard ratio of 0.91 (95% confidence interval: 0.83–0.98; p = 0.015). Subjects in the highest tertile of MeDi adherence had a 39 to 40% lower risk of AD compared to those in the lowest tertile. The findings suggest that higher adherence to the MeDi may reduce the risk of AD and cognitive decline. The study also highlights the potential benefits of composite dietary patterns in capturing the multidimensional effects of diet on health.This study investigates the association between adherence to the Mediterranean diet (MeDi) and the risk of Alzheimer's disease (AD). The research involved 2,258 community-based nondemented individuals in New York, who were prospectively evaluated every 1.5 years. Higher adherence to the MeDi was associated with a lower risk of AD, with a hazard ratio of 0.91 (95% confidence interval: 0.83–0.98; p = 0.015). Subjects in the highest tertile of MeDi adherence had a 39 to 40% lower risk of AD compared to those in the lowest tertile. The findings suggest that higher adherence to the MeDi may reduce the risk of AD and cognitive decline. The study also highlights the potential benefits of composite dietary patterns in capturing the multidimensional effects of diet on health.