A substantial prospective cohort investigation reveals that elderly individuals who incorporate a greater quantity of virgin olive oil—a fundamental element of the Mediterranean dietary pattern—exhibit a slower trajectory of cognitive decline and a more varied gut microbial ecosystem over a two-year observation period. In contrast, elevated consumption of standard refined olive oil was correlated with diminished microbial diversity and an accelerated rate of cognitive deterioration.
Extra-virgin olive oil, a major component of the Mediterranean diet, protects against cognitive decline. Image credit: Steve Buissinne.
Virgin olive oil stands as a pivotal component of the Mediterranean diet, characterized by its rich concentration of phenolic compounds possessing anti-inflammatory and antioxidant attributes.
Prior preclinical investigations employing both laboratory models and animal subjects had indicated neuroprotective capacities; however, empirical human data substantiating a connection between olive oil consumption, the gut microbiota, and cognitive function has remained scarce.
The latest findings are derived from participants enrolled in the PREvención con DIeta MEDiterránea-Plus (PREDIMED-Plus) study, an extensive, ongoing clinical trial designed to ascertain the impact of dietary and lifestyle modifications on cardiovascular and metabolic well-being.
“This marks the inaugural prospective human study that has specifically scrutinized the influence of olive oil on the intricate interplay between the gut microbiota and cognitive performance,” stated Dr. Jiaqi Ni, a researcher affiliated with the Universitat Rovira I Virgili.
The investigative team monitored over 650 adults, aged between 55 and 75 years, who were classified as overweight or obese and presented a high susceptibility to cognitive decline, yet were cognitively sound at the commencement of the research.
Throughout a two-year duration, the researchers meticulously documented participants’ olive oil intake, assessed their gut microbial profiles, and evaluated their performance across a comprehensive spectrum of cognitive assessments.
A higher degree of virgin olive oil consumption was found to be associated with enhancements or sustained levels in global cognition, executive functions, and linguistic abilities.
Conversely, a greater intake of common olive oil, predominantly a refined product, was identified as being linked to a reduction in gut microbial diversity and a more rapid cognitive decline.
“In an era marked by the escalating prevalence of cognitive impairment and dementia, our discoveries underscore the paramount importance of elevating dietary quality, and specifically, of advocating for extra virgin olive oil over its more refined counterparts as a potent, straightforward, and readily available strategy for safeguarding cerebral health,” commented Universitat Rovira I Virgili researchers Nancy Babio and Stephanie Nishi.
To delve deeper into the potential mechanisms by which virgin olive oil might confer cognitive advantages, the scientists analyzed fecal samples collected at the study’s outset.
Individuals exhibiting higher virgin olive oil consumption demonstrated a more diverse gut microbiota and distinct microbial community structures when juxtaposed with those who consumed less.
Subsequent analyses suggested that particular gut bacterial species might serve as explanatory factors for the observed cognitive benefits.
Modifications in the prevalence of certain microbial taxa, such as Adlercreutzia, appeared to statistically mediate the correlation between virgin olive oil intake and improved overall cognitive function, thereby corroborating the hypothesis that dietary patterns can influence brain vitality via the gut-brain axis.
“This body of work reinforces the notion that the quality of dietary fats we ingest is as critical as their quantity,” remarked Dr. Jordi Salas-Salvadó, also from the Universitat Rovira I Virgili.
“Beyond its cardioprotective effects, extra virgin olive oil can also contribute to the preservation of the brain throughout the aging process.”
“The involvement of a specific microbial profile in conferring these benefits opens avenues for novel nutrition-based preventive interventions aimed at preserving cognitive faculties.”
The research initiative was formally published in the scientific journal Microbiome.
_____
J. Ni et al. 2026. Total and different types of olive oil consumption, gut microbiota, and cognitive function changes in older adults. Microbiome 14, 68; doi: 10.1186/s40168-025-02306-4
