Scientists say this type of olive oil could boost brain power

A study led by researchers from the Human Nutrition Unit at the Universitat Rovira i Virgili (URV), the Pere Virgili Health Research Institute (IISPV) and CIBERobn points to a meaningful link between extra virgin olive oil, gut bacteria, and brain health.

Study explores olive oil, gut microbiome, and brain health

"This is the first prospective study in humans to specifically analyze the role of olive oil in the interaction between gut microbiota and cognitive function," explains Jiaqi Ni, first author of the article and researcher at the URV's Department of Biochemistry and Biotechnology.

The research followed 656 adults between the ages of 55 and 75 who were overweight or obese and had metabolic syndrome -- a set of risk factors that increase the likelihood of developing cardiovascular disease. Over a two-year period, as part of the PREDIMED-Plus project, scientists tracked participants' diets, including their intake of virgin and refined olive oil, along with detailed analyses of their gut microbiota. They also monitored changes in cognitive performance over time.

Virgin olive oil linked to better cognition and gut diversity

The findings showed clear differences depending on the type of olive oil consumed. Participants who regularly used virgin olive oil experienced improvements in cognitive function and had a more diverse gut microbiota, which is widely considered a sign of better intestinal and metabolic health. In contrast, those who consumed refined olive oil tended to show a decline in microbiota diversity over time.

Researchers also identified a specific group of gut bacteria, known as Adlercreutzia, that may be tied to these benefits. Its presence could serve as an indicator of the positive relationship between virgin olive oil consumption and preserved cognitive function. These results suggest that part of the oil's brain-supporting effect may come from how it reshapes the gut microbiome.

Why extra virgin olive oil stands out

The difference between extra virgin and refined olive oil largely comes down to how they are produced. Extra virgin olive oil is obtained using mechanical methods, which help preserve its natural compounds. Refined olive oil, on the other hand, undergoes industrial processing to remove impurities.

While this refining process improves shelf life and taste consistency, it also reduces beneficial components such as antioxidants, polyphenols, vitamins and other bioactive substances. According to Jiaqi Ni, "not all olive oils have benefits for cognitive function," highlighting the importance of choosing extra virgin varieties.

Quality of dietary fats matters for brain health

These findings add to growing evidence that diet plays a key role in both cardiovascular and cognitive health through its influence on the gut microbiota. Jordi Salas-Salvadó, principal investigator of the study, emphasizes the importance of choosing high-quality fats: "This research reinforces the idea that the quality of the fat we consume is as important as the quantity; extra virgin olive oil not only protects the heart, but can also help preserve the brain during aging."

He also notes that identifying a specific microbial profile linked to these benefits "paves the way for new nutrition-based prevention strategies to preserve cognitive functions."

A simple dietary change for an aging population

Co-directors Nancy Babio and Stephanie Nishi highlight the broader implications of the findings as populations continue to age. "At a time when cases of cognitive decline and dementia are on the rise, our findings drive home the importance of improving diet quality, and in particular prioritizing extra virgin olive oil over other refined versions as an effective, simple and accessible strategy for protecting brain health."

The study was led by the Human Nutrition Unit at the URV's Department of Biochemistry and Biotechnology, with contributions from the Pere Virgili Health Research Institute (IISPV-CERCA) and the CIBER area on the Physiopathology of Obesity and Nutrition (CIBEROBN) of the Carlos III Health Institute. Researchers from the PREDIMED-Plus consortium also participated, along with collaborators from international institutions including Wageningen (Netherlands) and Harvard (United States).