A large prospective cohort study has revealed that older adults consuming more virgin olive oil, a vital element of the Mediterranean diet, experience slower cognitive decline and enhanced gut microbiota diversity over two years. Conversely, higher consumption of common refined olive oil correlates with decreased microbial diversity and accelerated cognitive decline.
Extra virgin olive oil, a cornerstone of the Mediterranean diet, protects against cognitive decline. Image credit: Steve Buissinne.
Virgin olive oil is a key ingredient of the Mediterranean diet, packed with phenolic compounds known for their anti-inflammatory and antioxidant benefits.
While prior laboratory and animal research hinted at neuroprotective effects, human studies linking olive oil, gut microbiota, and cognitive function remain sparse.
This groundbreaking finding stems from participants in the PREvención con DIeta MEDiterránea-Plus (PREDIMED-Plus) study, an extensive ongoing trial designed to explore how dietary and lifestyle changes influence cardiovascular and metabolic health.
“This is the first prospective human study analyzing the role of olive oil in the relationship between gut microbiota and cognitive function,” stated Dr. Giaki Ni, a researcher from Rovira i Virgili University.
Researchers monitored over 650 adults aged 55 to 75, who were overweight or obese and at high risk for cognitive decline, yet cognitively healthy at the study’s onset.
During a two-year period, they assessed participants’ olive oil intake, gut microbiome profiles, and performance on a comprehensive range of cognitive tests.
Increased consumption of virgin olive oil was linked to improved or sustained overall cognition, executive function, and language proficiency.
In stark contrast, high consumption of common refined olive oil appeared to diminish gut microbial diversity and accelerate cognitive decline.
“As cases of cognitive decline and dementia rise, our findings underscore the necessity of enhancing diet quality. Prioritizing extra virgin olive oil over refined options emerges as a simple yet effective strategy to safeguard brain health,” emphasized researchers Nancy Babio and Stéphanie Nisi from Rovira i Virgili University.
To uncover why virgin olive oil may positively impact cognitive function, scientists analyzed baseline stool samples.
Those who consumed higher amounts of virgin olive oil exhibited greater gut microbiota diversity and a more cohesive microbial community structure compared to those who consumed less.
Further analysis indicated that specific gut bacteria may elucidate the cognitive advantages. Changes in the prevalence of particular microbial species, such as adlerkreuzia, appeared to mediate the relationship between virgin olive oil intake and enhanced cognitive performance, reinforcing the concept that diet influences brain health via the gut-brain axis.
“This study highlights that the quality of fats we consume matters as much as their quantity,” remarked Dr. Jordi Salas Salvado, also from Rovira y Virgili University.
“Extra virgin olive oil not only benefits heart health but also plays a vital role in protecting brain function as we age.”
“The discovery that microbial profiles contribute to these benefits opens avenues for new nutrition-based prevention strategies to maintain cognitive function.”
Find out more in the study published in the journal Microbiome.
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J.nee et al. 2026. Changes in total and different types of olive oil intake, gut microbiota, and cognitive function in older adults. Microbiome 14, 68; doi: 10.1186/s40168-025-02306-4
Source: www.sci.news
