A groundbreaking study published in Nature has found that closely following the Mediterranean diet can significantly reduce the risk of dementia, even in individuals with the highest genetic predisposition to Alzheimer’s. Researchers from Brigham and Women’s Hospital and Harvard Medical School tracked more than 5,700 people over 34 years and discovered that those who adhered to a plant-rich Mediterranean diet had a 35% lower risk of dementia if they carried two copies of the APOE4 gene — a major risk factor for Alzheimer’s.
Lead author Yuxi Liu told CNN that the findings are especially striking for people who previously believed their genetic destiny was fixed. “Not only did following a Mediterranean diet reduce the probability of developing dementia by 35% in people with two APOE4 genes, but higher adherence further reduced their risk,” Liu said.
Why the Mediterranean diet matters The diet emphasizes vegetables, fruits, legumes, nuts, whole grains, olive oil, and fish while limiting red and processed meats. Researchers noted that people with the APOE4 gene show distinctive metabolic profiles that respond dramatically to these nutrient-dense foods. Improved nutrient digestion, energy production, and brain tissue repair may explain the significant drop in dementia risk.
“This is a stop-the-presses finding,” neurologist Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases in Florida, told CNN. He emphasized that genes are not destiny. “If the risk of dementia in a person in the highest risk category can be cut by 35% just by following a specific diet, imagine the power of combining this with other lifestyle changes such as exercise, sleep, and stress reduction.”Longevity lessons from other diets The findings echo a growing body of research linking plant-forward diets to healthier, longer lives. Earlier this year, a study presented by the European Society of Cardiology compared the Mediterranean diet with the Planetary Health Diet (PHD). Both were associated with a lower risk of early death, with the Mediterranean diet lowering mortality risk by 21% and the PHD by 22%.
The PHD, developed by the EAT-Lancet Commission, emphasizes whole grains, fruits, vegetables, legumes, nuts, and unsaturated oils, while limiting red meat, dairy, and added sugars. Like the Mediterranean pattern, it supports both health and sustainability. Researchers identified four foods — fruits, dairy, unsaturated oils, and nuts — as particularly powerful for longevity, reinforcing the message that dietary choices can reshape health outcomes. Hope beyond genetics For patients and families worried about dementia, the implications are profound. In one clinical trial led by Dr. Isaacson, patient Simon Nicholls — who also carries two APOE4 genes — significantly reduced amyloid and tau levels in his blood through lifestyle changes. Remarkably, his hippocampus, the brain’s memory hub, even increased in volume after adopting a healthier diet and exercise routine. These studies converge on one powerful insight: while we cannot change our genes, we can influence how they play out. By embracing nutrient-rich diets like the Mediterranean and PHD, people may not only lower their dementia risk but also extend their overall lifespan. As Dr. Liu and her colleagues note, the research underscores that Alzheimer’s is not an inevitable fate. Instead, the path to better brain health may begin with something as simple as what’s on our plate.
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