Scientists have discovered that the Mediterranean diet, already known to reduce dementia risk, provides the strongest brain protection to those who need it most: people with high genetic risk for Alzheimer’s disease.
High-Risk Groups Saw Greatest Benefits
Alzheimer’s disease has a strong genetic component, with heritability estimated at up to 80 percent. One gene, apolipoprotein E (APOE), is the strongest risk factor.
The study, recently published in Nature Medicine, tracked 4,215 women and 1,490 men for up to three decades. It found that people carrying two copies of the APOE4 gene variant, which increases Alzheimer’s disease risk by up to 12 times, experienced the largest reduction in dementia when following Mediterranean eating patterns.
Over the study period, those following Mediterranean-style diets showed lower rates of dementia and slower mental decline overall. However, the protective effect was strongest among those with two copies of the APOE4 gene.
Researchers studied how diet and genetics relate to Alzheimer’s risk by analyzing participants’ food questionnaires, blood samples, and genetic data, and then monitoring them for signs of dementia over time.
How the Mediterranean Diet Supports Brain Health
The mechanisms linking diet and gene expression in Alzheimer’s disease aren’t fully understood, but researchers suspect that epigenetic factors—changes in gene activity influenced by environmental factors such as diet—may play a role.
The researchers theorized that eating more of the Mediterranean diet is associated with increased levels of healthy fats in the body, which may support brain health. The diet also increases levels of certain natural compounds, such as piperine, betaine, and pantothenic acid, that are known to protect brain cells.
Additionally, the diet might influence substances related to caffeine breakdown that have antioxidant and brain-protecting qualities, especially in those with the APOE4 gene.
“These findings suggest that dietary strategies, specifically the Mediterranean diet, could help reduce the risk of cognitive decline and stave off dementia by broadly influencing key metabolic pathways,” first author Yuxi Liu, a research fellow at Brigham and Women’s Hospital, part of Mass General Brigham, said in a statement.
“This recommendation applies broadly, but it may be even more important for individuals at a higher genetic risk.”
Foods That Feed the Brain
The Mediterranean diet emphasizes foods that help support neural health, Dr. Brynna Connor, a board-certified family medicine physician specializing in antiaging and regenerative medicine who was not involved in the study, told The Epoch Times. These include fatty fish, leafy green vegetables, whole grains, and berries.
Fatty fish have substantial brain-supporting benefits, primarily because of their high levels of omega-3 fatty acids, which are essential nutrients that support cognitive processes, guard against neurodegenerative conditions, and help maintain overall brain health. Research has shown a causal link between omega-3 intake and a slower rate of brain aging and reduced cognitive decline. People who eat more omega-3-rich foods often have greater amounts of gray matter, a key part of the brain that supports memory, learning, and decision-making.
“When people think of ‘fatty fish,’ they typically defer to salmon; however, fatty fish options also include mackerel, bluefin tuna, sardines, striped bass, herring, whitefish, and anchovies,” Connor said.
According to her, walnuts are another good source of omega-3 fatty acids. She said research has found that people who regularly eat walnuts show improved memory and cognitive function compared with those who don’t.
Leafy greens in the Mediterranean diet also help maintain brain function.
“Packed with brain-boosting nutrients and antioxidants, leafy green vegetables like spinach, kale, and/or arugula play a crucial role in protecting neural pathways,” Connor said.
Research conducted on older adults ages 58 to 99 found a strong correlation between frequent consumption of leafy greens and improved cognitive health, with those who ate the most leafy greens showing brain function comparable to that of people more than a decade younger.
“To maximize the benefits of leafy green vegetables, aim for at least one serving a day, with other choices including collard greens, bok choy, and/or Swiss chard to help guard against age-related cognitive decline,” Connor said.
Emily Feivor, a dietitian at Northwell Health who was not involved in the study, noted that the Mediterranean diet’s low processed food content helps “prevent inflammation linked to cognitive impairment.”
Why More Research Is Needed
“One reason we wanted to study the Mediterranean diet is because it’s the only dietary pattern that has been causally linked to cognitive benefits in a randomized trial,” Liu said. The team wanted to understand whether genetic background affected these benefits.
The research focused on well-educated people of European ancestry. Scientists emphasized that more diverse populations need to be studied to confirm that these findings apply universally.
Currently, genetics and blood metabolite testing aren’t common in clinical Alzheimer’s risk assessments, although that may change as research progresses.
“In future research, we hope to explore whether targeting specific metabolites through diet or other interventions could provide a more personalized approach to reducing dementia risk,” Liu said.
As of now, the specific mechanisms linking diet and APOE gene expression in relation to Alzheimer’s disease are not fully understood. Researchers are exploring whether dietary factors influence gene activity and how this might affect disease risk.
Epigenetic factors are considered a possible area of influence. Epigenetics refers to changes in gene activity that do not alter the underlying DNA sequence but can be shaped by environmental influences such as diet. Modifications such as DNA methylation (chemical changes that switch genes on or off) and histone modification (changes to proteins that control gene activity) may play a role in how genetic risk factors such as APOE contribute to Alzheimer’s disease development.
