A study has found that the Mediterranean diet can reduce the risk of dementia and slow the rate of cognitive decline.
A joint research team involving Brigham and Women's Hospital in Massachusetts, Harvard T.H. Chan School of Public Health, the Massachusetts Institute of Technology (MIT), and the Broad Institute of Harvard University announced on the 25th in the international journal 'Nature Medicine' that the Mediterranean diet helps reduce the risk of dementia.
The Mediterranean diet is a dietary pattern that focuses on fruits, vegetables, nuts, whole grains, fish, and olive oil while reducing red meat and processed foods. It has already been shown multiple times to be effective in preventing cardiovascular diseases and metabolic disorders.
The research team aimed to investigate how the Mediterranean diet reduces the risk of dementia and affects blood metabolic products related to cognitive health. They comprehensively analyzed the dietary habits and blood metabolites of 4,215 women and 1,490 men over several decades, along with genetic information and the occurrence of dementia over time.
As a result, those who diligently followed the Mediterranean diet had a lower incidence of dementia, and cognitive decline appeared later. The effect of the Mediterranean diet was most strongly observed in the high-risk group for Alzheimer's with two copies of the APOE4 gene variant. 'APOE4' is considered one of the strongest risk factors for Alzheimer's disease. It is known that a person with one copy of this gene variant has a risk of developing Alzheimer's 3 to 4 times higher than that of the general population, and those with two copies are at an astonishing 12 times higher risk.
Yuxi Liu, a postdoctoral researcher at Harvard T.H. Chan School of Public Health, noted, "The Mediterranean diet suggests that it can have a wide-ranging impact on major metabolic pathways, reducing the risk of cognitive decline and helping to prevent dementia." This implies that what we eat directly affects our brain health.
However, the research team added that "most of the study subjects were well-educated of European descent, so further research is needed to see if the same effects are found in groups of different races or living environments."
The effects of the Mediterranean diet have been confirmed in several previously published studies. According to a meta-analysis of a total of 23 related papers, those who adhered well to the Mediterranean diet had a 11% to 30% lower risk of cognitive disorders such as dementia and Alzheimer's disease compared to those who did not. The international research team conducting this study stated that "the Mediterranean diet has the potential as a key component of public health strategies aimed at mitigating the global impact of cognitive decline and dementia."
References
Nature Medicine (2025), DOI: https://doi.org/10.1038/s41591-025-03891-5
Geroscience (2025), DOI: https://doi.org/10.1007/s11357-024-01488-3