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Health
Mediterranean diet mitigates genetic predisposition for dementia, research indicates
Most significant advantage for those with the greatest susceptibility to Alzheimer’s disease
Recent studies indicate that adhering to a Mediterranean-style diet might assist in countering an individual’s genetic susceptibility to Alzheimer’s disease.
The research, published in Nature Medicine and spearheaded by researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard, discovered that individuals at the highest genetic risk for Alzheimer’s disease who adopted a Mediterranean diet—rich in vegetables, fruits, nuts, whole grains, and limited in red and processed meats—experienced a slower cognitive decline and a more substantial reduction in dementia risk compared to those with a lower genetic risk.
“One motivation for examining the Mediterranean diet is that it is the sole dietary pattern linked causally to cognitive enhancements in a randomized trial,” stated the study’s lead author Yuxi Liu, a research associate in the Department of Medicine at Brigham and Women’s Hospital and a postdoctoral fellow at the Harvard Chan School and the Broad Institute. “We sought to discover if this benefit varied among individuals with different genetic makeups, as well as to investigate the role of blood metabolites, the small compounds representing how the body processes nutrition and maintains normal functions.”
“These results propose that dietary interventions could aid in lessening the threat of cognitive decline and delaying dementia by broadly influencing essential metabolic pathways.”
Yuxi Liu, study’s lead author
Over recent decades, scientists have gained deeper insights into the genetic and metabolic foundations of Alzheimer’s diseaseand similar dementias. These conditions represent some of the most prevalent causes of cognitive decline among the elderly. Alzheimer’s disease is known to possess a significant genetic component, with heritability estimated up to 80 percent.
A specific gene, apolipoprotein E, or APOE, has emerged as the most prominent genetic risk factor for sporadic Alzheimer’s disease—the more common type, which manifests later in life and is not directly inherited in a predictable manner. Individuals carrying one copy of the APOE4 variant face a three to four times greater risk of developing Alzheimer’s. Those with two copies of the APOE4 variant have a staggering 12-fold increased risk compared to those without.
To investigate how the Mediterranean diet might decrease dementia risk and affect blood metabolites associated with cognitive health, the team analyzed data from 4,215 women in the Nurses’ Health Study, tracking participants from 1989 to 2023 (average age 57 at the start). To corroborate their findings, researchers examined similar data from 1,490 men in the Health Professionals Follow-Up Study, which ran from 1993 to 2023.
Researchers assessed long-term dietary habits via food frequency questionnaires and analyzed participants’ blood samples for a wide array of metabolites. Genetic information was utilized to determine each participant’s inherited risk for Alzheimer’s disease. Participants were then monitored over time for instances of new dementia cases. A subset of 1,037 women underwent periodic cognitive evaluations via telephone.
They discovered that those adhering to a Mediterranean-style diet had a diminished risk of developing dementia and exhibited a slower cognitive decline. The protective impact of the diet was most pronounced in the high-risk group with two copies of the APOE4 gene variant, suggesting that dietary habits may counteract genetic risk.
“These results imply that dietary strategies, particularly the Mediterranean diet, could play a role in mitigating cognitive decline and delaying dementia by broadly impacting crucial metabolic pathways,” Liu stated. “This guidance is relevant for the general population, but may hold even greater importance for those at heightened genetic risk, such as individuals with two copies of the APOE4 genetic variant.”
A limitation of the study was that the sample consisted predominantly of well-educated individuals of European descent. Further research is necessary in more diverse populations.
Moreover, while the study uncovers significant correlations, genetics and metabolomics are still not routinely included in most clinical risk assessment models for Alzheimer’s disease. Many individuals are often unaware of their APOE genetic status. Additional efforts are required to translate these findings into everyday medical practices.
“In future investigations, we aspire to determine whether targeting specific metabolites through dietary or other methods could offer a more tailored approach to reducing dementia risk,” Liu remarked.
This research received partial funding from the National Institutes of Health.
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