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Mediterranean Diet May Protect Against Memory Loss, Dementia

Eating a Mediterranean diet that’s rich in fish, vegetables, and olive oil may protect the brain from protein buildup and shrinkage that can lead to Alzheimer’s disease, according to a new study recently published in Neurology, the medical journal of the American Academy of Neurology.

The study evaluated abnormal proteins called amyloid and tau. Amyloid forms into plaques, while tau forms into tangles. Both are found in the brains of people with Alzheimer’s disease but also may be found in the brains of older people with normal cognition.

“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 buildup that can lead to memory loss and dementia,” says study author Tommaso Ballarini, PhD, of the German Center for Neurodegenerative Diseases in Bonn, Germany. “These results add to the body of evidence that show what you eat may influence your memory skills later on.”

The study examined 512 people, 169 of whom were cognitively normal and 343 of whom were identified as being at higher risk of developing Alzheimer’s disease.

Researchers determined how closely people followed the Mediterranean diet based on their answers to a questionnaire asking how much they ate of 148 items over the previous month. People who often ate healthful foods typical of the Mediterranean diet, such as fish, vegetables, and fruit, and only occasionally ate foods not typical of the Mediterranean diet, such as red meat, received the highest scores, for a maximum score of nine.

Cognitive skills were assessed with an extensive test set for Alzheimer’s disease progression that analyzed five different functions, including language, memory, and executive function. All the participants had brain scans to determine their brain volume. In addition, the spinal fluid of 226 was tested for amyloid and tau protein biomarkers.

Researchers then evaluated how closely someone followed the Mediterranean diet and the relationship to their brain volume, tau and amyloid biomarkers, and cognitive skills.

After adjusting for factors such as age, sex, and education, researchers found that in the area of the brain most closely associated with Alzheimer’s disease, every point lower people scored on the Mediterranean diet scale was equal to almost one year of brain aging.

When looking at amyloid and tau in people’s spinal fluid, those who didn’t follow the diet closely had higher levels of biomarkers of amyloid and tau pathology than those who did.

When it came to a test of memory, people who didn’t follow the diet closely scored worse than those who did.

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

A limitation of the study is that people’s diets were self-reported in the questionnaire. People may have made errors recalling exactly what and how much they ate.

— Source: American Academy of Neurology