Can Mediterranean diet cut Alzheimer’s dementia risk? – Deseret News

The food that people choose could have a powerful impact on the risk of developing dementia.

That’s according to a new study that found following a Mediterranean diet reduces the risk of Alzheimer’s — and it has the greatest impact for those with the highest genetic risk, people who carry two copies of the APOE4 gene.

The study was led by researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health and the Broad Institute of MIT and Harvard. It was published in Nature Medicine.

“One reason we wanted to study the Mediterranean diet is because it is the only dietary pattern that has been causally linked to cognitive benefits in a randomized trial,” study first author Yuxi Liu, a research fellow in the Department of Medicine at Brigham and Women’s Hospital, a founding member of the Mass General Brigham health care system, and a postdoctoral fellow at Harvard and Broad, said in a news release.

“We wanted to see whether this benefit might be different in people with varying genetic backgrounds, and to examine the role of blood metabolites, the small molecules that reflect how the body processes food and carries out normal functions.”

The release said Alzheimer’s has “a strong genetic component, with heritability estimated at up to 80%.” One gene in particular is implicated: apolipoprotein E (APOE) has the strongest genetic risk for the more common type of Alzheimer’s that developed later in life and is not directly inherited in a predictable pattern, per the researchers. It has four variants and people inherit one from each of their parents. Those with one copy of the APOE4 gene variant have three to four times greater change of developing Alzheimer’s. The risk is 12-fold for those with two APOE4 copies, compared to those without that variant.

The Mediterranean diet

The Mediterranean diet is largely plant-based, with lots of fruits, vegetables, whole grains, nuts, beans and legumes. Extra virgin olive oil is the main fat source. The diet can contain fish, poultry and dairy — especially fish that contain a lot of omega-3 fatty acids. Red meat and sweets are discouraged, as is butter, according to Cleveland Clinic. The clinic’s webpage includes a Mediterranean food list.

The Mediterranean diet is also deemed a healthy choice for those looking to reduce their risk of coronary artery disease or other forms of heart disease. The diet has also been linked to maintaining a healthy body weight, improving the gut biome, lowering risk of certain cancers and other health benefits.

About the study

The researchers looked at data from 4,215 women in the Nurses’ Health Study, average age 57 at baseline, following their data from 1989 to 2023. They also looked at similar data from 1,490 men in the Health Professionals Follow-up Study, using data from 1993-2023.

To figure out dietary patterns, they looked at food frequency questionnaires and blood samples for a broad range of metabolites. They also considered genetic risk. Participants were followed over time to see if they developed dementia and a subset of 1,037 women underwent regular telephone-based cognitive testing.

The release said that those following a Mediterranean-style diet had lower risk of dementia and also slower cognitive decline. The protective effect was strongest in the high-risk group with two copies of the APOE4 variant, “suggesting that diet may help offset genetic risk.”

The researchers note that people may not know their APOE status or whether they have the APOE4 allele, adding “more work is needed to translate these findings into routine medical practice.” Liu said they hope to explore whether using diet or other interventions to target specific metabolites could create a more focused, personalized approach to reducing dementia risk.

Among limitations, they note the study conducted in well-educated individuals of European descent, which might impact whether it can be generalized to the public at large. And dementia outcomes were “based on self-reported physician diagnoses and death records, which may introduce misclassification.”