A new research study from the Universitat Rovira i Virgili in Spain suggests that extra virgin olive oil may help protect brain health as people grow older. It may also improve the balance of bacteria living in the human gut, which is crucial for overall health and may contribute to enhanced cognitive function. Scientists compared extra virgin olive oil with refined olive oil. They found clear differences in how each one affects health.
The study focused on virgin olive oil and refined olive oil. Virgin olive oil is an important part of the Mediterranean diet. It is already known for supporting heart and metabolic health. However, its possible effects on the brain through the digestive system were not fully understood before this research, particularly regarding how the bioactive compounds in virgin olive oil may influence cognitive function and neuroprotection.
The research team came from the Human Nutrition Unit at Universitat Rovira i Virgili. They also worked with the Pere Virgili Health Research Institute and CIBERobn. They studied 656 people aged between 55 and 75 years. All participants were overweight or obese and had metabolic syndrome. This condition increases the risk of heart disease and other health problems. Data was collected over two years through the PREDIMED-Plus project. Researchers recorded the types of olive oil people consumed and studied gut bacteria. They also tracked changes in cognitive function over time.
People who consumed virgin olive oil showed better cognitive function than those who used refined olive oil. They also had more diverse gut microbiota. A diverse microbiota is linked to better digestion and overall health. In contrast, refined olive oil was linked with lower bacterial diversity over time. Researchers also identified a group of bacteria called Adlercreutzia. This bacteria may be a marker of the positive effects of virgin olive oil on the brain.
The difference between the two oils comes from how they are made. Virgin olive oil is produced only by mechanically pressing olives. Refined olive oil goes through industrial processing to remove impurities. This process also removes many natural compounds like antioxidants and polyphenols. These compounds are known to support health in different ways, such as reducing inflammation and lowering the risk of chronic diseases. Because of this, refined oil has fewer beneficial nutrients. Researchers believe the evidence explains why virgin olive oil is more beneficial.
The lead researcher said that the quality of fats in the diet matters as much as the amount eaten. Extra virgin olive oil may protect both the heart and the brain. It may also support healthy ageing by keeping gut bacteria balanced, which in turn can contribute to improved cognitive function and potentially reduce the risk of memory decline and dementia. Scientists say identifying specific bacteria linked to diet effects could help future prevention strategies, such as developing targeted dietary recommendations that promote the growth of beneficial gut bacteria to enhance cognitive function and reduce the risk of dementia. This is important as cases of memory decline and dementia are increasing in older populations worldwide. Improving diet quality could be a simple and affordable way to protect brain health over time.
Scientists refer to the close connection between the gut and the brain as the gut-brain axis. This system allows bacteria in the digestive tract to influence brain activity. Healthy gut bacteria can produce substances that reduce inflammation in the body. Lower inflammation is linked with better memory and thinking skills. Extra virgin olive oil may support this system by feeding beneficial bacteria. Refined olive oil may not provide the same support because it lacks natural compounds that promote gut health and the growth of beneficial bacteria, which are essential for reducing inflammation and enhancing cognitive function.
The study also has some limitations to consider. It focused on people who already had metabolic risk factors. Results may be different in healthier populations. Researchers say more studies are needed to confirm long-term effects. However, the findings still give strong evidence that diet quality matters for brain health. They also support the idea that small daily food choices can affect long-term ageing outcomes.
The research suggests extra virgin olive oil may be a simple dietary choice with meaningful health benefits. It links better gut bacteria diversity with improved thinking ability in older adults. Experts say this supports wider use of Mediterranean-style eating patterns for healthy ageing. It highlights the importance of choosing high-quality oils every day.
The study was led by the Human Nutrition Unit of the Department of Biochemistry and Biotechnology at URV, with support from IISPV-CERCA and CIBEROBN at the Carlos III Health Institute.
