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Mediterranean diet may reduce Alzheimer’s risk, study finds

Scientists say it counters genetic risk in some people

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Mark Huffman
Reporter

Mark Huffman has covered consumer issues since 2004, with a special focus on protecting and empowering older adults. A former news correspondent for the Associated Press Radio Network, Westwood One, and ConsumerAffairs, Mark brings decades of journalistic experience to RetirementLiving.com. He is passionate about giving consumers a voice and helping them make informed decisions. Mark has also created educational content, including Senior Scam Alert, a video resource designed to help seniors recognize and avoid fraud. He holds a B.A. from the University of Kentucky and lives with his family in Richmond, Virginia.
Lots of Mediterranean on a table: Photo by Alexandra Tran on Unsplash

Photo by Alexandra Tran on Unsplash

Key Insights

  • People with two copies of the APOE4 gene show unique biological changes that raise their risk of Alzheimer’s disease.
  • Certain fats and amino acids in the blood are linked to dementia risk differently depending on a person’s genes.
  • The Mediterranean diet appears especially protective for those at the highest genetic risk.

A major new study published in Nature Medicine reveals that the risk of developing Alzheimer’s disease may depend not only on genes but also on how those genes interact with the body’s metabolism and diet. One diet in particular, the Mediterranean diet, appears to significantly reduce the risk.

In a study published in the journal Nature Medicine, researchers found that people who inherit two copies of the APOE4 gene, a powerful genetic driver of Alzheimer’s, have a distinct biological profile that makes them especially vulnerable to dementia.

The study followed more than 5,700 adults – 4,215 women in the Nurses’ Health Study and 1,490 men in the Health Professionals Follow-Up Study – over several decades. By analyzing genetic data, blood metabolites, and dietary habits, scientists were able to map how different biological pathways contribute to dementia risk.

Metabolic fingerprints of dementia

The team identified 57 metabolites, molecules produced when the body processes food and energy, that were linked to dementia risk in ways that varied by genetics. For example, cholesteryl esters and sphingomyelins, both types of fats, were most strongly tied to higher dementia risk in people with two APOE4 copies. At the same time, certain glycerides seemed to protect only this group.

In people carrying other risk-related genetic variants, such as in the APP gene, different metabolites played a role. One example was dimethylguanidino-valeric acid, which was more strongly connected to dementia risk in those carriers.

The research also highlighted the Mediterranean diet, rich in fruits, vegetables, fish, nuts, and olive oil, as a powerful tool against dementia. For people with the genes, adherence to this diet had a particularly strong effect in reducing harmful metabolites and boosting protective ones. Nearly 40% of the diet’s benefit in reducing dementia risk in these individuals could be explained by its influence on metabolites, the study’s authors wrote. This suggests that targeted dietary strategies might help offset even the strongest genetic risks for Alzheimer’s disease.

Health experts at UC Davis Health point to other benefits of the Mediterranean diet, including lower risk of heart disease, stroke, diabetes, certain cancers, improved longevity, and better overall metabolic health.

The diet lowers the risk of developing type 2 diabetes and supports metabolic health via high fiber intake, slow-digesting carbohydrates, and emphasis on healthy fats such as olive oil and fatty fish.