A Mediterranean-style diet may help reduce the risk of dementia, especially for people who carry a higher genetic risk of developing Alzheimer’s disease.
That’s the finding of a new study led by researchers from Mass General Brigham, the Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard.
The study was published in the journal Nature Medicine.
For decades, researchers have been studying how diet affects brain health. Among many eating patterns, the Mediterranean diet—rich in fruits, vegetables, olive oil, fish, and whole grains—has been repeatedly linked to benefits for the brain and overall health.
This new research adds another piece to the puzzle: people who are genetically more likely to get Alzheimer’s may benefit even more from this way of eating.
The team looked at data from two large health studies: 4,215 women in the Nurses’ Health Study and 1,490 men in the Health Professionals Follow-Up Study. Participants were followed for several decades.
At the beginning of the study, their average age was 57. Over time, researchers tracked their diets, tested their memory and thinking, and collected blood samples to measure substances called metabolites—tiny molecules that show how the body processes food and performs daily functions.
The researchers also examined the participants’ genes, especially looking for a version of a gene called APOE4. People with one copy of this gene are three to four times more likely to get Alzheimer’s, and people with two copies are at even greater risk—about 12 times more likely.
The results were clear. People who ate more like the Mediterranean diet were less likely to get dementia. They also experienced slower memory decline over the years. And the biggest benefit was seen in those with two copies of the APOE4 gene—people at the highest genetic risk.
This means that even if someone has genes that put them at risk for Alzheimer’s, their choices may still make a difference. A healthy diet like the Mediterranean diet could help protect the brain and lower that risk.
The study also found that the Mediterranean diet seemed to influence key metabolic pathways—how the body breaks down food and uses it. This may be one of the ways the diet helps protect the brain. Still, more research is needed to fully understand how these changes happen and how we can use this knowledge in everyday medical care.
One thing to keep in mind: the people in this study were mostly white, well-educated, and from similar backgrounds. Future studies need to include more diverse populations to see if the same benefits apply to everyone.
For now, this research gives new hope that eating well may help keep the brain healthier for longer—even for those at higher genetic risk.
If you care about dementia, please read studies about Early heart rhythm problem linked to higher dementia risk and findings of Green leafy vegetables may help reduce Alzheimer’s risk.
For more about dementia, please read studies about Research shows an important cause of frontotemporal dementia and findings of New way to detect Lewy body disease early, a leading cause of dementia.
The study is published in Nature Medicine.
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