Virgin Olive Oil Tied to Slower Cognitive Decline through Gut Microbiome Changes
Large prospective cohort study finds older adults who consume more virgin olive oil – a key part of the Mediterranean diet – have slower cognitive decline and a more diverse gut microbiota over two years of follow-up; in contrast, higher consumption of common refined olive oil was linked to lower microbial diversity and faster decline.
Extra virgin olive oil, a major component of the Mediterranean diet, protects against cognitive decline. Image credit: Steve Buissinne.
Virgin olive oil is a cornerstone of the Mediterranean diet and is rich in phenolic compounds with anti-inflammatory and antioxidant properties.
Previous laboratory and animal studies have suggested neuroprotective effects, but human evidence linking olive oil, gut microbiota, and cognition is limited.
The new findings draw on participants from the PREvención con DIeta MEDiterránea-Plus (PREDIMED-Plus) study, a large, ongoing trial designed to examine how diet and lifestyle changes affect cardiovascular and metabolic 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,” said Dr. Jiaqi Ni, researcher at Universitat Rovira I Virgili.
Researchers followed more than 650 adults ages 55 to 75 who were overweight or obese and at high risk of cognitive decline but in good cognitive health at the start of the research.
Over a two-year period, they tracked olive oil consumption, gut microbiota profiles, and participants’ performance on a comprehensive battery of cognitive tests.
Higher consumption of virgin olive oil was associated with improvements or preservation in overall cognition, executive functions, and language skills.
In contrast, higher consumption of common, largely refined olive oil was associated with reduced microbial diversity in the gut and faster cognitive decline.
“At a time when cases of cognitive decline and dementia are increasing, our findings highlight 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 to protect brain health,” said Nancy Babio and Stephanie Nishi, researchers at Rovira I Virgili University.
To explore why virgin olive oil might benefit cognition, the scientists analyzed stool samples collected at baseline.
People who consumed more virgin olive oil had a more diverse gut microbiota and distinct microbial community structures compared to those who consumed less.
Further analysis suggests that specific gut bacteria may help explain the cognitive benefits.
Changes in the abundance of certain microbial species, such as Adlercreutziaappears to statistically mediate the link between virgin olive oil consumption and improved general cognitive performance, supporting the idea that diet can influence brain health via the gut-brain axis.
“This research reinforces the idea that the quality of the fats we consume is as important as the quantity,” said Dr. Jordi Salas-Salvadó, also from Rovira I Virgili University.
“Extra virgin olive oil not only protects the heart, but may also help preserve the brain during aging.”
“The fact that a microbial profile plays a role in these benefits opens the way to new prevention strategies based on nutrition to preserve cognitive functions. »
The study was published in the journal Microbiota.
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J.Ni and others. 2026. Total and different types of olive oil consumption, gut microbiota and changes in cognitive functions in older adults. Microbiota 14, 68; doi: 10.1186/s40168-025-02306-4
