A new study from researchers in Spain suggests that consuming virgin olive oil instead of refined olive oil may help boost cognitive function in older adults — possibly by improving the gut microbiome.

The study followed 656 adults aged 55 to 75 who were overweight or obese and had metabolic syndrome, all risk factors for cardiovascular disease. Over two years, researchers tracked participants’ intake of both virgin and refined olive oil while analyzing their gut microbiota — the community of microorganisms living in the digestive tract.

Results showed that those who consumed virgin olive oil — a key component of the Mediterranean diet — had better cognitive performance and greater diversity in their gut microbiome. Researchers also identified a specific bacterium, Adlercreutzia, as a potential contributor to improved brain function.

Refined olive oil undergoes processing that can reduce or remove beneficial compounds, including antioxidants, polyphenols, and vitamins that support brain health.

Jordi Salas-Salvadó, the study’s principal investigator, emphasized the importance of oil quality. “This research reinforces the idea that the quality of the fat we consume is as important as the quantity,” he said. “Extra virgin olive oil not only protects the heart but can also help preserve the brain during aging.”

Researchers say the findings highlight how diet — particularly foods that support a healthy gut microbiome — may play a role in protecting cognitive health. As rates of dementia and cognitive decline continue to rise, choosing higher-quality fats like extra virgin olive oil could be a simple step toward better brain health.