What the Study Found
Olive oil has long been associated with heart health. Now, a new Spanish study from Universitat Rovira i Virgili suggests extra virgin olive oil may also protect brain health as people age. Researchers published their findings in the journal Microbiome.
The study tracked over 600 adults. All participants were between the ages of 55 and 75. They were also overweight or obese and had metabolic syndrome — a condition linked to increased risk of heart disease. Researchers monitored their consumption of both virgin and refined olive oil for two years. They also tracked changes in gut microbiota — the community of living microorganisms in the human digestive system.
This research marks a significant step forward. “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 lead author Jiaqi Ni of the URV’s Department of Biochemistry and Biotechnology.
How Gut Bacteria Protect the Brain
The Gut-Brain Connection
The study revealed a clear link between gut bacteria diversity and cognitive performance. Participants who consumed virgin olive oil showed greater diversity in their gut microbiome. Researchers identified this diversity as an important marker of both intestinal and metabolic health.
Moreover, researchers pinpointed a specific genus of bacteria called Adlercreutzia as a potential indicator of brain preservation. Higher levels of this bacteria appeared in participants who regularly used virgin olive oil. This suggests the oil actively supports the growth of bacteria that shield the brain from age-related decline.
Why Diversity Matters
A diverse gut microbiome helps regulate inflammation, supports immune function, and produces compounds that influence brain activity. Consequently, a healthy gut may directly contribute to sharper thinking, better memory, and stronger focus in older adults. Thus, what you eat does not just affect your waistline — it shapes your mental performance too.
Virgin vs. Refined Olive Oil
How Processing Changes Everything
Not all olive oils deliver the same health benefits. The key difference lies in how each type gets processed. Virgin olive oil undergoes minimal processing. As a result, it retains natural antioxidants, polyphenols, and vitamins that support human health.
Refined olive oil, however, goes through industrial treatments to remove impurities and improve taste and shelf life. Unfortunately, these processes strip away the very compounds — polyphenols and antioxidants — that make olive oil beneficial. In short, refining the oil removes its brain-boosting power.
The Research Comparison
Participants who consumed refined olive oil showed less gut microbiome diversity over time. Furthermore, they did not experience the same improvements in cognitive function. This contrast highlights a key takeaway from the research. “Not all olive oils have benefits for cognitive function,” Ni noted plainly.
Key Cognitive Benefits Observed
Memory, Attention, and Executive Function
Researchers conducted follow-up cognitive assessments to measure any changes in brain performance. Participants who consumed extra virgin olive oil showed measurable improvements across three areas: memory, attention, and executive function. These improvements emerged over the two-year study period.
Participants who used refined olive oil, by contrast, did not show similar gains. Therefore, the type of olive oil consumed — not simply the amount of fat — appears to determine whether cognitive benefits occur.
What Experts Are Saying
Principal investigator Jordi Salas-Salvadó emphasized the broader implications of the findings. “Extra virgin olive oil not only protects the heart but can also help preserve the brain during aging,” he stated in a press release. His comments reinforce a growing body of evidence that dietary fat quality plays a critical role in long-term health outcomes.
Additionally, the study supports the idea that what aging adults eat directly influences brain preservation. Choosing extra virgin olive oil over refined alternatives could therefore become a simple, actionable step toward maintaining cognitive function in later life.
Limitations to Keep in Mind
Observational Design and Self-Reported Data
Despite its promising findings, the study carries some limitations. First, it used an observational design — meaning researchers observed participants rather than conducting controlled experiments. As a result, the study does not prove that extra virgin olive oil alone caused the cognitive improvements.
Second, the study relied on self-reported dietary information. Self-reporting introduces the possibility of inaccuracies. Participants may not have recalled their olive oil consumption with full precision.
Population-Specific Results
Third, the study focused on older Mediterranean adults with specific metabolic risk factors. Consequently, the findings may not apply to younger populations or those without metabolic syndrome. Researchers also noted that factors such as smoking habits and lower education levels appeared more frequently among participants using refined olive oil. These variables may have influenced results, even after statistical adjustment.
What This Means for You
The evidence points toward a practical and accessible lifestyle choice. Swapping refined olive oil for extra virgin olive oil at home costs little effort. Yet, based on this research, it could support both gut health and brain function as you age.
Furthermore, this study adds to the growing science behind the Mediterranean diet — a dietary pattern long associated with longevity and cognitive resilience. Including extra virgin olive oil as a regular part of meals may offer protection that goes well beyond the kitchen.
As always, consult a healthcare professional before making significant dietary changes, especially if you manage existing health conditions.
