According to recent studies, people who follow a Mediterranean-style diet are less likely to develop dementia and experience slower cognitive decline. The study, published in the journal Nature Medicine, suggests that even genetic risk factors can be mitigated. Alzheimer’s disease (AD) and AD-related dementias (AD/ADRD) have a substantial genetic basis, and APOE4 homozygotes are increasingly recognized as a distinct genetic subtype, according to the study. A team led by researchers at the Harvard T.H. Chan School of Public Health found that it may be especially protective for people with two copies of the APOE4 gene variant.

“To identify genotype-specific metabolic pathways and modifiable risk factors, we integrated genetic data from 4,215 women and 1,490 men in prospective cohorts”

Below, we’ll explain in detail how this type of research is put into practice. To begin, let’s talk about the study published in Nature Medicine, in which the researchers state: “To identify genotype-specific metabolic pathways and modifiable risk factors, we integrated genetic, plasma metabolomic, and dietary data from 4,215 women and 1,490 men in prospective cohorts.”

The study, called ‘Interplay of genetic predisposition, plasma metabolome and Mediterranean diet in dementia risk and cognitive function’ says that “environmental factors, especially diet, interact with genetics to further shape the metabolome by introducing exogenous metabolites and modulating key metabolic processes, such as inflammation, energy production and oxidative stress.” So, what we eat is what we are, in other words. The human body works this way, so everything has an impact. The food we feed our bodies influences not only our satiety, but also our blood pressure, hydration, our heart, our emotions and, of course, our brain.

The researchers investigated the Mediterranean diet in people with specific genetic backgrounds

Over a period of three decades, researchers were able to see how people (more than 4,200 women and almost 1,500 men) who followed Mediterranean-style diets—rich in vegetables, fruits, nuts, and whole grains, and low in red and processed meats—were less likely to develop dementia and experienced slower cognitive decline. The researchers investigated the Mediterranean diet in people with specific genetic backgrounds, while also analyzing blood metabolites: molecules that can act as indicators of how the body is functioning and processing food.

In fact, the researchers found the Mediterranean diet regulated metabolites related to dementia, particularly in participants whose genes put them at high risk for Alzheimer’s. “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,” says epidemiologist Yuxi Liu of the Harvard Chan School. On the other hand, the researchers have also suggested that doctors could do more to include genetic and metabolite testing when assessing patients’ Alzheimer’s risks. Alzheimer’s is a complex condition, with risk factors known to include sleep quality, diet, and mental health.

The findings are based on highly educated individuals of European descent and do not show direct cause and effect

As we point out throughout the article, there is an important genetic element, because having one or two copies of the APOE gene significantly increases the chances of developing the disease. While the association is significant, the findings are based on highly educated individuals of European descent and do not show direct cause and effect, suggesting that there may be unknown factors that have an impact that is currently unknown.

The final conclusion of the research reads as follows: “We observed that individuals with greater adherence to the Mediterranean Diet had a significantly lower risk of dementia and better cognitive function. Notably, these protective associations with dementia risk were more pronounced among APOE homozygotes compared with non-carriers and heterozygotes, although no clear trend was observed when stratifying by ADRD PRS.”