The research had a large sample size of 90,000 medical professionals who were part of two long-term studies on health and lifestyle factors. The studies spanned nearly 30 years, with the average participant being 56 years old when they began in 1990.

Over the next 28 years, the data showed that nearly 5,000 of those participants died from dementia. However, the study authors observed that risk was 28% lower for participants who regularly consumed olive oil (more specifically, they were consuming over half a tablespoon per day) compared to those who rarely used it.

Interestingly, this finding was independent of overall dietary choices, suggesting that a simple swap of olive oil when you might use margarine or mayonnaise could have brain-healthy benefits, regardless of the rest of your diet.

And while this research only shows a link, as opposed to offering an explanation for why, the researchers concluded that replacing just one daily teaspoon of margarine or mayonnaise with olive oil could lower the risk of dying from dementia by 8 to 14%.

It’s worth mentioning, as well, that this isn’t the first time research has suggested olive oil has brain benefits. One 2022 study1 published in Nutrients found that people with mild cognitive impairment who were supplemented with 30 mL of extra-virgin olive oil (EVOO) per day for six months experienced significant improvements in behavioral and clinical dementia rating (CDR) scores.

The researchers from that study also discovered that the EVOO helped enhance the function of the blood-brain barrier (BBB), while the breakdown and dysfunction of the BBB are associated with neurodegenerative diseases like Alzheimer’s disease.

Other studies2 also suggest olive oil consumption might reduce the accumulation of amyloid plaques3, which are also involved in the onset and progression of Alzheimer’s.