A new study suggests that changing what we eat could help protect our brain as we age.
Researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard found that following a Mediterranean-style diet may reduce the risk of developing dementia, especially in people with a higher genetic risk of Alzheimer’s disease.
The Mediterranean diet focuses on eating more fruits, vegetables, whole grains, nuts, legumes, olive oil, and lean proteins like fish, while limiting red meat and processed foods.
Past studies have already shown that this way of eating can benefit heart health and reduce inflammation. Now, scientists believe it may also help slow cognitive decline and reduce the risk of diseases like Alzheimer’s.
This new study, published in the journal Nature Medicine, looked at more than 5,700 people over several decades. The researchers wanted to know if the Mediterranean diet could make a difference depending on a person’s genetic makeup.
They paid special attention to a gene called APOE. This gene comes in different forms, and one of them—called APOE4—is linked to a higher chance of developing Alzheimer’s disease later in life.
People with one copy of the APOE4 variant are three to four times more likely to get Alzheimer’s, while those with two copies face up to 12 times the risk. But this study found something hopeful: people who had the highest genetic risk and followed a Mediterranean diet had a significantly lower risk of dementia compared to those who didn’t follow the diet.
The researchers analyzed data from two major studies. One included over 4,200 women from the Nurses’ Health Study, followed from 1989 to 2023. The second group involved nearly 1,500 men from the Health Professionals Follow-Up Study, followed from 1993 to 2023. Participants were between the ages of 57 and 65 when the study began.
Participants filled out food questionnaires over the years to track their eating habits.
They also gave blood samples, which were tested for hundreds of small molecules called metabolites—these are chemicals that show how our body processes food and maintains health. Researchers also looked at genetic data to calculate each person’s risk for Alzheimer’s.
The results were clear. People who stuck closely to the Mediterranean diet had a lower risk of developing dementia and showed slower memory loss over time.
The diet seemed to offer the most protection to those who carried two copies of the APOE4 gene. This suggests that even people who are more likely to get Alzheimer’s can lower their risk by making healthy food choices.
The study also revealed that the Mediterranean diet may protect the brain by affecting the body’s metabolism—the way it uses and breaks down nutrients. This broad influence on biological processes could explain why the diet is so helpful.
One limitation of the study is that most participants were well-educated and of European background. The researchers say more studies are needed in people of other races, ethnicities, and backgrounds.
Also, while the study provides strong evidence of a link between diet and dementia risk, most people don’t know their genetic risk. And current medical care doesn’t usually include metabolomics or genetic testing for Alzheimer’s. So more work is needed to bring these findings into everyday healthcare.
Lead author Dr. Yuxi Liu said that future research could look at targeting certain metabolites with diet or other treatments to create personalized strategies for preventing dementia.
For now, the takeaway is simple: eating a healthy Mediterranean diet may be one of the best ways to protect your brain—especially if you have a family history of Alzheimer’s.
If you care about brain health, please read studies about Scientists find connection between fungus and Alzheimer’s disease and findings of Scientists find links between COVID-19 and Alzheimer’s disease.
For more about Alzheimer’s disease, please read studies about Research shows root cause of Alzheimer’s disease and new treatment and findings of Scientists find the link between eye disease glaucoma and Alzheimer’s disease.
The study finding is published in Nature Medicine.
Copyright © 2025 Knowridge Science Report. All rights reserved.
