New research suggests that extra-virgin olive oil may protect the brain from Alzheimer’s disease symptoms.

Alzheimer’s disease is estimated to affect approximately 5 million people in the United States. The neurodegenerative disease is progressive and cannot yet be cured or reversed.

But new research moves closer to a prevention – and potentially reversing – strategy, by studying the effects of extra-virgin olive oil on the cognitive performance (thinking) and brain health of mice.

Extra-virgin olive oil is a key component of the Mediterranean diet, which is a diet rich in fruits, vegetables, whole grains, olive oil, and nuts.

The new study – published in the journal Annals of Clinical and Translational Neurology – was carried out by a team of researchers from the Lewis Katz School of Medicine at Temple University in Philadelphia, PA.

Lead investigator Dr. Domenico Praticò states that several studies have singled out olive oil and hailed it as the main reason why the Mediterranean diet is linked to so many health benefits. Mostly because of the high amount of monounsaturated fat, and high polyphenol content.

Dr. Praticò and team used a traditional Alzheimer’s mouse model to study the effect of EVOO. The rodents were modified to have the three main characteristics of Alzheimer’s disease: memory impairment, the buildup of amyloid plaques, and neurofibrillary tangles.

Dr. Praticò and colleagues split the rodents into two groups: one group was fed a chow diet with extra-virgin olive oil, and the other group received a regular chow diet with no added oil.

Alzheimer’s characteristics begin to develop in a rodent model quite early on, so in this experiment, the oil was added to the diet when the mice were 6 months old, before any symptoms could have appeared.

The researchers evaluated the mice’s cognitive abilities by administering tests for their spatial memory, working memory, and learning skills.

In terms of general appearance, no differences were noted between the two animal groups.

But, when the mice were 9 months and 12 months old, the mice that had been fed the extra-virgin olive oil diet performed much better in the cognitive tests.

Dr. Praticò and his team also analyzed the brain tissue of these mice, and the studies revealed striking differences between the appearance and functioning of the nerve cells. Improvement in healthy brain tissue was dramatic in the EVOO group.

Next, the researchers plan to introduce olive oil at a later stage, when Alzheimer’s symptoms will have already emerged. In the case of mice, this would mean at 12 months of age.

“Usually when a patient sees a doctor for suspected symptoms of dementia, the disease is already present,” Dr. Praticò explains. “We want to know whether olive oil added at a later time point in the diet can stop or reverse the disease.”

Dr. Edward Catalano