Why the Mediterranean diet protects the brain from signs of Alzheimer’s disease: study

Nutrition

By Brooke Steinberg

The Mediterranean diet continues to prove why it’s been named the No. 1 best diet overall by the U.S. News & World Report for seven years in a row.

A new study published in the journal JAMA Neurology found that sticking to the Mediterranean diet can keep a person’s mind sharp into old age — even if the brain shows signs of Alzheimer’s disease.

People who followed the diet scored higher on cognitive functionality tests, despite markers for dementia in the brain after death, researchers from Rush University in Chicago found.

The Med diet is derived from the traditional diets of 21 countries that border the Mediterranean Sea — where fresh greens, fruits, fish, nuts and olives abound. It involves eating plant-based foods, grains and lean poultry along with healthy doses of extra-virgin olive oil.

While it doesn’t focus on a specific nutrient or food group, the Med diet instead stresses the importance of focusing on quality and filling your plate with a wide range of foods, such as fruits, vegetables, seafood, olive oil and whole grains.

Using data from the Rush Memory and Aging Project, a study with autopsy data from 1997 to 2022 with up to 24 years of follow-up, researchers analyzed 586 subjects who died at an average age of 91.

Participants had self-reported life factors to the project, including smoking, alcohol consumption, exercise frequency, a Mediterranean diet and cognitive activity score.

The healthy lifestyle score was based on these factors and was ranked from one to five, and higher scores indicated a healthier lifestyle and better cognitive function closer to death.

These scores were compared to the cognitive function score from the test less than a year before the participant’s death.

Post-death, the brains were removed from the subject’s bodies, and the researchers looked for signs of amyloid beta and tau tangles — two of the main signs of Alzheimer’s.

Dementia is not a specific disease — it’s a term for the impaired ability to remember, think or make decisions that interferes with doing everyday activities, according to the Centers for Disease Control and Convention. Alzheimer’s is the most common form of dementia.

Even if participants’ brains showed signs of Alzheimer’s, their healthy lifestyle still appeared to protect them somewhat from cognitive decline, the study showed.

It’s thought that the diet can help with cognitive decline because it is so balanced — making you full longer and less likely to munch on junk food and snacks.

An October 2023 study found that the Mediterranean diet may help reduce symptoms of post-traumatic stress disorder via the gut microbiome.

Other recent studies showed that those who stick to the diet may reduce their odds of premature death by 29%, while women alone have shown a nearly 25% lower chance of heart disease and early death.

An earlier study from Harvard University said the Mediterranean diet was one of four common healthy eating patterns that can help reduce the risk of early death by up to 20%.