A groundbreaking new study indicates that adhering to a Mediterranean diet may help offset the genetic risk of Alzheimer’s disease. This is particularly significant for those with a high genetic propensity to develop this debilitating condition. The research affirms that the Mediterranean diet, renowned for its health benefits, could play a crucial role in preventing cognitive decline and dementia, even in individuals with a high genetic susceptibility.
Genetics and ‘sporadic’ Alzheimer’s disease
‘Sporadic’ Alzheimer’s disease, the most common type, typically develops later in life and is not directly linked to family history. Instead, it arises due to a combination of genetics, environmental factors, and lifestyle choices. The Apolipoprotein E (APOE) gene is particularly implicated in this, with the APOE4 variant being the strongest genetic risk factor for late-onset AD. Individuals with one copy of this variant have a three to four times higher risk of developing Alzheimer’s, while those with two copies face an eight to twelve times higher risk.
The new study on the Mediterranean diet and Alzheimer’s risk
The study, published in the journal Nature Medicine, analyzed data from 4,215 women who participated in the U.S. Nurses’ Health Study, tracked for 34 years. The researchers also verified their findings using data from 1,490 male participants of the U.S. Health Professionals Follow-Up Study. The participants’ adherence to the Mediterranean diet was gauged using their Mediterranean Diet (MedDiet) index scores. The study found that those who adhered closely to the Mediterranean diet had a significantly lower risk of dementia and better cognitive function.
MedDiet score components
The MedDiet scores, ranging from zero to nine, were determined based on participants’ regular intake of certain dietary components. These components included vegetables, whole fruits, nuts, whole grains, pulses, and fish. A higher intake of monounsaturated fat compared to saturated fat was also awarded points, as was a lower consumption of red and processed meat.
Mediterranean diet most protective for highest risk group
The study revealed that the Mediterranean diet’s greatest benefits were observed in those with the highest genetic predisposition to AD. For individuals with two copies of the APOE4 gene, every one-point increase in the MedDiet score was linked to a 35% lower risk of dementia. Among individuals with one copy of the gene, each one-point increase in the MedDiet score correlated with a 4% reduced dementia risk.
Potential mechanisms of the Mediterranean diet in preventing dementia
The Mediterranean diet-derived metabolites may influence metabolic pathways in the brain, thereby reducing the risk of cognitive decline and dementia, especially in individuals carrying two copies of the APOE4 gene. For instance, the researchers found cognitive benefits associated with betaine, a phytochemical plentiful in beets, spinach, and whole grains, in people at high genetic risk for AD. In addition, higher intake of anti-inflammatory carotenoids, found in a variety of vegetables and fruits, has also been associated with slower cognitive decline, especially in APOE4 carriers. These findings add to the growing evidence that a healthy diet is a vital tool for the prevention of dementia, even for those with a high genetic predisposition.
Article by Leslie Beck, a Toronto-based private practice dietitian, director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD
