An apple a day might keep the doctor away, but a diet rich in olive oil could prevent cognitive impairment.

At least that’s what researchers at Temple University are suggesting. They found that consuming extra virgin olive oil in early adulthood could protect against a form of dementia.

For the study, mice were put on a diet that featured extra virgin olive oil at the human age equivalent of 30 to 40 years. After six months — which would make the mice similar in age to 60-year-old humans — tau deposits had been reduced by about 60%. Tau protein has been linked to the formation of various types of dementia.

Domenico Praticò, M.D., said he and colleagues were encouraged by the discovery.

“The realization that extra virgin olive oil can protect the brain against different forms of dementia gives us an opportunity to learn more about the mechanisms through which it acts to support brain health,” he said.

Full findings appear in the journal Aging Cell.