Could extra-virgin olive oil help prevent Alzheimer's disease?

A new study from Temple University's Lewis Katz School of Medicine adds to evidence that EVOO is good for the brain.

The study was done in mice engineered to develop brain changes typical of Alzheimer's.  Studies involving mice often don't hold up when tried with people, but senior investigator Domenico Pratico, a professor in the Center for Translational Medicine who studies neurodegenerative diseases, thinks his findings have promise.  There's already evidence, he said, that people who eat a Mediterranean diet — olive oil is a key component — have a lower risk of developing dementia as they age.  Temple's study, published Wednesday in the Annals of Clinical and Translational Neurology, might explain why.

The study used mice that have developed memory problems and also the hallmark pathological features of Alzheimer's disease, clumps of a protein called amyloid and tangles made of tau. Twelve of them ate only their regular chow, pellets made of ground wheat, corn and a milk protein, with added vitamins and minerals.  Ten were also given small amounts of extra virgin olive oil every day for six months. (They did not get fatter than the other mice.)  Pratico, who worked with a researcher at Sapienza University of Rome, wanted to mimic how people would eat the oil.  The team used cold-pressed, first-extraction oil, a type that is pricey but carried by typical grocery stores.  The mice were given tests of memory and learning at six, nine, and 12 months old, and graded by researchers who did not know what the mice had been eating.

The mice that had eaten olive oil did about 40 percent better on tests of working memory — the kind you use to hold thoughts in your mind while performing a task — and a more advanced maze-learning activity.  Researchers then studied the inner workings of their brains.  The EVOO-eating mice had 60 percent less abnormal amyloid and 40 percent less tau in their brains.  There also was evidence that the connections between nerve cells were functioning better and that their cells were doing a better job of clearing refuse, which could help them rid the brain of the errant proteins, Pratico said.

"We are very excited," Pratico said.  "It's super-promising."

To do the same test in people, Pratico said, study subjects would need to eat a tablespoon of olive oil a day for six to eight years.

He is now studying the impact of canola oil, a cheaper and widely used oil.  He plans to look at regular, less-expensive olive oil than EVOO and to test olive oil in older mice that have started exhibiting Alzheimer's symptoms.

Pratico thinks there's enough evidence to support health benefits from olive oil to justify using it himself.  He also likes it.  "I've been doing this for a while." he said.

For more on how olive oil is made and what's in it, check out this video from the American Chemical Society: