Virgin olive oil protects cognitive health thanks to gut microbiota

Virgin olive oil is considered one of the fundamental pillars of the Mediterranean diet and is widely recognized for its benefits for cardiovascular and metabolic health. However, its direct influence on the brain through the digestive system had not been explored in depth in humans. A new study led by researchers from CIBEROBN at the Human Nutrition Unit of the Universitat Rovira i Virgili (URV), part of the Institut d’Investigació Sanitària Pere Virgili (IISPV), reveals that virgin olive oil (VOO) may play a key role in protecting cognitive function through the gut microbiota.

“This is the first prospective study in humans that specifically analyzes 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 Department of Biochemistry and Biotechnology at URV. To conduct the study, the research team worked with data from 656 individuals aged between 55 and 75 who were overweight or obese and had metabolic syndrome—a group of risk factors that increase the likelihood of cardiovascular disease. This information, collected as part of the PREDIMED-Plus project over a two-year period, also included the consumption of different types of olive oil—virgin and refined—the composition of the gut microbiota, and a follow-up of changes in cognitive function.

Better cognitive function and a more diverse microbiota

The results reveal that people who consumed virgin olive oil instead of refined olive oil showed better progression in cognitive function and greater diversity in their gut microbiota, an important marker of intestinal and metabolic health. In contrast, the consumption of refined olive oil was associated with a less diverse microbiota over time. In addition, the research identified a genus of bacteria within the gut microbiota, called Adlercreutzia, as a possible indicator of the beneficial association between virgin olive oil consumption and the preservation of cognitive function. This finding suggests that part of the benefits of consuming this type of oil for brain function could be explained through its impact on the composition of the gut microbiota.

So what makes virgin olive oil healthier than refined olive oil? The main difference lies in the production process: VOO is obtained exclusively through mechanical procedures, while refined oil undergoes industrial treatments that remove impurities. The problem is that these processes also degrade natural antioxidants, polyphenols, vitamins, and other bioactive compounds that are beneficial to health. Taking this into account, Jiaqi Ni warns that “not all olive oils have benefits for cognitive function” and that it is necessary to prioritize the consumption of virgin olive oils over refined ones.

Quality is as important as quantity

Results such as those from this research help advance our understanding of the mechanisms linking cardiovascular and cognitive health with the gut microbiota. Jordi Salas-Salvadó, the study’s principal investigator, highlights the importance of olive oil quality as a central element of the Mediterranean diet: “This research reinforces the idea that the quality of the fat we consume is just as important as the quantity; VOO not only protects the heart but may also help preserve the brain during aging.” The URV professor also emphasizes the significance of having identified a microbial profile involved in these benefits: “it opens the door to new nutrition-based prevention strategies to preserve cognitive function.”
 
 
 

At the same time, researchers Nancy Babio and Stephanie Nishi, co-directors of the study, highlight the relevance of the findings in the current context of population aging: “At a time when cases of cognitive decline and dementia are increasing, our results reinforce the idea that improving the quality of the diet—and particularly prioritizing virgin olive oil over refined versions—can be an effective, simple, and accessible strategy to protect brain health.”

The completion of this study was made possible thanks to the leadership of the Human Nutrition Unit of the Department of Biochemistry and Biotechnology at URV and the participation of institutions such as the Institut d’Investigació Sanitària Pere Virgili (IISPV-CERCA) and CIBEROBN of the Instituto de Salud Carlos III. The project also involved collaboration with researchers from the PREDIMED-Plus consortium and from international universities such as Wageningen University (Netherlands) and Harvard University (United States).