Mediterranean diet improves cognition, protects against proteins linked to AD

Following a Mediterranean diet protected against memory decline and mediotemporal atrophy, according to a study published in Neurology.

The findings indicated that a Mediterranean-like diet can decrease amyloid and tau proteins. Evidence from the study also suggested that this kind of diet contributes to brain maintenance.

“Our study suggests that eating a diet that’s high in unsaturated fats, fish, fruits and vegetables and low in dairy and red meat may actually protect your brain from the protein build-up that can lead to memory loss and dementia,” Tommaso Ballarini, PhD, a postdoctoral researcher at the German Center for Neurodegenerative Diseases, said in a press release announcing the study’s findings. “These results add to the body of evidence that show what you eat may influence your memory skills later on.”

Ballarini and colleagues examined the impact of a Mediterranean-like diet on cognitive function and in vivo biomarkers for Alzheimer’s disease in cognitively normal participants and individuals with a higher risk for developing AD. The study comprised 512 participants, with similar rates of men and women, including 169 individuals with normal cognition and 343 with increased AD risk (53 participants with relatives with AD; 209 with subjective cognitive decline; and 81 with mild cognitive impairment. Mean age of the cohort was 69.5 years.

The researchers used a self-reported Food Frequency Questionnaire to track diet adherence. Participants chose from nine categories to describe how often they ate typical Mediterranean foods and non-typical Mediterranean foods. Ballarini and colleagues measured brain volume outcomes using a voxel-based morphometry on T1-MRI and cognitive performance with an “extensive” neuropsychological battery. They assessed AD-related biomarkers, including amyloid beta and plasma phosphorylated tau at threonine 181, or p-tau181, in 226 patients by testing their spinal fluid. The mean period between baseline interview and the final food questionnaire was 41.5 weeks.

The findings revealed that better Mediterranean diet adherence led to greater mediotemporal gray matter volume (Family-Wise Error-corrected P < .05), better memory (P = .038) and less amyloid (P = .008) and p-tau181 pathology (P = .004). Ballarini and colleagues linked each point increase in adherence to the Mediterranean diet with an increase in memory performance that they correlated with nearly one year less of brain aging. Additionally, the researchers found that the Mediterranean diet “favorably moderated” the relationship between the amyloid beta 42/40 ratio, p-tau181 and mediotemporal atrophy.

The study results were found to be consistent after correcting for APOE e4 status, according to Ballarini and colleagues.

“More research is needed to show the mechanism by which a Mediterranean diet protects the brain from protein build up and loss of brain function, but findings suggest that people may reduce their risk for developing Alzheimer’s by incorporating more elements of the Mediterranean diet into their daily diets,” Ballarini said in the release.

Additionally, the researchers wrote that “longitudinal and dietary intervention studies should further examine this conjecture and its treatment implications.”

Reference:

American Academy of Neurology. Does eating a Mediterranean diet protect again memory loss and dementia? Available at: https://www.aan.com/PressRoom/Home/PressRelease/4891. Accessed May 5, 2021.