Is the Secret to Lowering Alzheimer's Risk in Your Diet?
The meals we consume might have a significant influence on our likelihood of developing dementia, as per a recent study. This research discovered that adhering to a diet common in the Mediterranean regions could decrease the risk of Alzheimer’s disease. This diet's impact is especially potent for those with a higher genetic risk for the disease, specifically those who have inherited two copies of the APOE4 gene.
Behind the Study
The study was conducted by a team of researchers from leading health and educational institutions. It was published in a reputable scientific journal. The first author of the study, a research fellow in the Department of Medicine at a well-known Hospital and postdoctoral fellow at prestigious universities, explained their interest in studying the Mediterranean diet.
The Mediterranean diet is the only diet that has been definitively linked to cognitive benefits in a randomized trial. The researchers were curious if this benefit might vary among people with different genetic backgrounds. They were also interested in examining the role of blood metabolites, the small molecules that reflect how the body processes food and carries out normal functions.
This study is particularly crucial as Alzheimer’s has a strong genetic component, with heritability estimated at up to 80%. The apolipoprotein E (APOE) gene is particularly implicated as it carries the strongest genetic risk for the more common type of Alzheimer’s that develops later in life and is not directly inherited in a predictable pattern. 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 primarily plant-based, with an emphasis on fruits, vegetables, whole grains, nuts, beans, and legumes. Extra virgin olive oil serves as the main source of fat. The diet can also include fish, poultry, and dairy — especially fish that are rich in omega-3 fatty acids. Red meat and sweets are discouraged, as is butter.
In addition to its potential benefits for dementia, the Mediterranean diet is also considered 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 gut health, lowering the risk of certain cancers, and offering other health benefits.
Details of the Study
The researchers analyzed data from 4,215 women in the Nurses’ Health Study, who were, on average, 57 years old at the beginning of the study. They followed these participants from 1989 to 2023. They also examined similar data from 1,490 men in the Health Professionals Follow-up Study, using data from 1993-2023.
To determine dietary patterns, they used food frequency questionnaires and blood samples for a broad range of metabolites. They also took into account genetic risk. Participants were tracked over time to see if they developed dementia, with a subset of 1,037 women undergoing regular telephone-based cognitive testing.
It was found that those who followed a Mediterranean-style diet had a lower risk of dementia and also experienced slower cognitive decline. The protective effect was strongest in the high-risk group with two copies of the APOE4 variant. This indicates that diet might help counteract genetic risk.
An interesting point is that many people may not know their APOE status or whether they have the APOE4 allele. The researchers hope to explore whether using diet or other interventions to target specific metabolites could create a more focused, personalized approach to reducing dementia risk.
However, the study does have some limitations. For instance, it was 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 some inaccuracies.