What did they investigate?
The researchers followed the patient for two years. 656 adults aged 55–75, who were without a diagnosis of dementia at the start of the study but were at increased risk of cognitive decline, partly due to overweight/obesity and metabolic syndrome. They assessed their olive oil intake using dietary questionnaires, collected stool samples for microbiome analysis, and compared their intake Virgin olive oil And Regular/refined olive oil, along with monitoring changes in cognitive function.

What did they find?
It was found that a higher consumption of Virgin olive oil was associated with better improvement or preservation of cognitive function over the follow-up period, as well as a greater diversity of gut bacteria. In contrast, higher intake of שמן זית מזוכך has been linked to a decrease in microbial diversity and accelerated cognitive decline. In addition, researchers identified a bacterium called Adlercreutzia As a possible mediator in part of the relationship between extra virgin olive oil and cognitive change.

What are the conclusions?
The study does not prove that extra virgin olive oil definitely “protects” against dementia, but it does strengthen the hypothesis thatFat quality Diet is also important for brain health, not just heart health. Extra virgin olive oil's contribution may be due to the fact that it preserves active compounds such as polyphenols and antioxidants, some of which are damaged during the refining process. The researchers emphasize that more research is needed, but the results reinforce the idea that brain health is also affected by what happens in the gut.

What are the recommendations for the public?
The practical message from the study is not to “drink olive oil,” but to prefer, as part of a balanced diet, Extra virgin/extra virgin olive oil Over olive oil מזוכך When possible. This fits well with the principles of the Mediterranean diet, which is already recognized as a diet that supports heart health, metabolism and perhaps cognitive function over time. It is important to remember: this is an observational study only, so this is Not a personal medical recommendation., but more interesting evidence of the importance of nutritional quality.

The main message from the study:
Not all olive oils are created equal when it comes to brain health. In this study, olive oil Virgin Linked to conservation Better of cognitive function and the gut microbiome Healthier, while olive oil מזוכך Linked to the trend Less good.

The full article:

• Link: https://link.springer.com/article/10.1186/s40168-025-02306-4
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• Reference:

Ni, J., et al. (2026). Total and different types of olive oil consumption, gut microbiota, and cognitive function changes in older adults. Microbiome, 14, Article 68. doi:10.1186/s40168-025-02306-4