Mediterranean diet lowers dementia risk, greatest in APOE4 homozygotes

A new wave of long-term research indicates that adopting a Mediterranean-style diet can significantly reduce the risk of dementia and slow cognitive decline, with the strongest protection seen among individuals carrying two copies of the APOE4 gene, the strongest genetic risk factor for sporadic Alzheimer’s disease. The findings suggest that dietary choices can modulate genetic risk and that blood metabolites may help explain how diet influences brain health over decades.

The analysis tracked more than 5,700 adults over roughly three and a half decades, combining data from multiple large cohorts. Participants’ eating patterns were assessed with detailed food questionnaires, while periodic cognitive testing and blood samples provided insight into metabolites and genetic risk. Across the groups, those who closely followed a Mediterranean-style pattern—rich in vegetables, fruits, nuts, whole grains, legumes, fish, and olive oil, and low in red and processed meats and excess alcohol—had a lower incidence of dementia and slower cognitive decline. In the subset of participants with two copies of APOE4, adherence to the diet was associated with a notably larger reduction in dementia...