SUNDAY, April 26, 2026 (HealthDay News) — When it comes to olive oil, not all are created equal. 

Extra virgin olive oil — the centerpiece of a Mediterranean diet — has benefits for your belly and your brain, new research shows. Refined olive oil, which is generally cheaper to buy, does not.

"Not all olive oils have benefits for cognitive function," said lead author Jiaqi Ni, a researcher at the University of Rovira i Virgili in Italy.

Ni’s team tracked the diets of 656 overweight or obese adults for two years, including their intake of virgin and refined olive oil.

Participants were between 55 and 75 years of age and had a constellation of heart disease risk factors known as metabolic syndrome. Researchers also watched for changes in participants’ thinking skills.

Those who regularly used what devotees often refer to as EVOO — extra virgin olive oil — saw improvements in cognitive function and had a more diverse population of microbes colonizing their guts.

That’s a sign of better metabolic and intestinal health.

Ni’s team tied these benefits to a specific group of gut bacteria known as Adlercreutzia. And its presence seems to underscore the positive link between EVOO use and cognitive function.

In other words, part of the oil’s brain benefit may come from how it reshapes the makeup of gut bacteria.

But why was EVOO found to be more helpful than refined olive oil? 

Chalk it up to how it’s made. 

EVOO is produced through mechanical methods that help preserve its beneficial compounds. Refined olive oil is processed to remove impurities, improve shelf life and provide consistent taste. 

That processing also reduces levels of good-for-you compounds like antioxidants, plyphenols and vitamins. 

"This research reinforces the idea that the quality of the fat we consume is as important as the quantity," principal investigator Dr. Jordi Salas-Salvadó, a professor of nutrition at University of Rovira i Virgili, said in a news release. 

"Extra virgin olive oil not only protects the heart, but can also help preserve the brain during aging," he said, adding that identifying the microbes contributing to these benefits "paves the way for new nutrition-based prevention strategies to preserve cognitive functions."

The findings were recently published in the journal Microbiome.

More information

The Mayo Clinic has more about the health benefits of olive oil.

SOURCE: University of Rovira i Virgili, news release, April 18, 2026