The best kind of olive oil for brain health

We’ve all absorbed the message by now: olive oil is good for us. It lowers “bad cholesterol”, fights inflammation and protects against various chronic diseases, including some types of cancer. However, recently, evidence is accumulating to suggest that its benefits extend beyond the body to the brain.

I wanted to know what it actually meant. What aspects of my cognition might it affect? How was it done? I also had practical questions – did it really have to be extra virgin (and therefore insanely expensive)? And how much do I have to consume to change?

The answers are more promising—and less limiting—than I expected. It turns out that olive oil may not be the only oil with brain health claims.

But first, the usual caveats. All nutrition research is notoriously difficult to do well. Studies often require participants to keep food diaries, and I probably don’t need to tell you how easy it is to “misremember” what we ate or quietly edit out less virtuous bites. For this reason and many others, truly robust food studies are relatively rare.

However, patterns can emerge. Observational studies can offer clues, especially when supported by experiments that probe the underlying biology. Put them together and we can build a reasonably convincing picture of which foods do what for our health.

Olive oil has been a major target recently. Much of the fuss stems from its central role in the Mediterranean diet—the most appealing of all diets, in my opinion. Who can object to advice that encourages more tomatoes, bread, fresh fish and olive oil with the occasional splash of red wine? Many studies have linked this way of eating to lower rates of heart disease, type 2 diabetes and – more recently – dementia.

At first glance, this seemed to contradict common dietary theories, as the Mediterranean diet is actually quite high in fat. But a closer look revealed that the main source of fat came from olive oil. This has prompted scientists to question whether olive oil itself is doing the heavy lifting. “The Mediterranean diet is much more effective if it includes extra virgin olive oil,” said the nutritionist Richard Hoffman at the University of Hertfordshire in the UK said The new scientist in 2024.

One influential study involved more than 7,000 people in Spain between the ages of 55 and 80. One group was given a 1-liter bottle of extra virgin olive oil each week and encouraged to consume approximately 4 to 5 tablespoons per day while following a Mediterranean diet. The second group ate similarly, but supplemented their diet with nuts instead of adding olive oil, while people in the third group were advised to reduce the amount of fat in their diet.

More than five years, those in the olive oil group had significantly lower rates of heart disease and stroke. For every 10 grams of oil consumed per day—a little less than one tablespoon—the risk of cardiovascular disease and mortality decreased by 10 and 7 percent, respectively.

Most scientists are now reasonably confident that olive oil helps reduce inflammation and improves cardiovascular health. But what does it do for the brain?

To find out, a large study published in 2024 examined data from more than 92,000 adults whose olive oil consumption was assessed every four years over nearly three decades. The result was clear: those who consumed more olive oil had a lower risk of dying from dementia.

While it’s reasonable to assume that people who eat higher amounts of olive oil may also lead generally healthier lives, the researchers tried to account for this and adjusted for factors such as body mass index, physical activity, smoking, socioeconomic status and overall diet. The association between olive oil and a lower risk of dementia-related deaths persisted.

They also modeled what might happen if participants replaced other fats with olive oil. “Additional benefits are seen if butter and other animal fats are replaced with olive oil,” he says Marta Guasch-Ferré at Harvard University. Their substitution analysis showed that replacing 1 teaspoon of margarine or mayonnaise with an equivalent amount of olive oil was associated with an 8 to 14 percent lower risk of dying from dementia.

Olive oil appears to have a protective effect on the brain, but why? Polyphenols seem to play a major role. Olive oil contains the highest number of these bioactive compounds of any oil. In plants, polyphenols help protect against stress, pests and other trauma. In humans, they appear to do something similar—clean up rogue harmful molecules called free radicals, reduce inflammation, and prevent the oxidation of “bad” fats in the body that can otherwise cause plaque to build up, which contributes to stroke.

Polyphenols are also beneficial to the gut microbes that feed on them, giving them energy to grow and interact with our immune system and calm inflammation.

Inflammation is behind many of our major killers, such as heart disease, but is also a known contributor to dementia, with growing evidence suggesting that Alzheimer’s disease may be initially triggered by inflammation in distant organs such as the skin, lungs or gut.

“Mechanistic evidence is mounting to support the hypothesis that olive oil … reduces the underlying pathology of Alzheimer’s disease and other neurodegenerative diseases,” says Guasch-Ferré.

Which oil is best?

Not all olive oils are created equal. Extra virgin olive oil is the “purest” or least processed. It is made by crushing the olives with a pit or stone and then squeezing the oil out using a centrifuge, thus preserving its polyphenols. Virgin olive oil is similar but has undergone a bit more processing, sometimes using chemicals or high temperatures. Then you have “regular” or “standard” olive oil, which is further processed and stripped of many of its beneficial compounds.

So does it really matter which one you buy? “We found that consumption of olive oil, regardless of its type, was associated with a lower risk of death,” says Guasch-Ferré. “The combination of healthy unsaturated fats in conjunction with other bioactive compounds is what makes olive oil one of the healthiest vegetable oils.”

However, a recent study published in January explored this difference in more detailinvestigating the effect of different olive oils on the microbiome and cognitive function of older adults. The results were startling.

The study evaluated 656 people aged 55 to 75 who were overweight and had metabolic syndrome. Participants who consumed more virgin olive oil showed improvements in several cognitive domains, while those who consumed standard olive oil experienced faster cognitive decline, even though both types of oil had similar amounts of fat.

The differences were linked to changes in the microbiome. Consumption of virgin olive oil was associated with greater microbial diversity, while standard olive oil was associated with less diversity. The researchers also identified one particular group of bacteria, Adlercreutziawhich appears to mediate about 20 percent of virgin olive oil’s effect on cognition.

This is very early evidence and only a small trial with a follow-up of only two years, so we have to take it with a grain of salt. Still, it offers a compelling look at how diet, bacteria, and brain health may be connected.

So where does that leave us? While standard olive oil appears to be beneficial for cardiovascular health due to its favorable fat profile, extra virgin olive oil adds something extra—a layer of beneficial compounds like polyphenols that may help protect the brain.

The good news (at least for your bank balance) is that olive oil doesn’t have to be alone. Other vegetable oils, including canola, corn and safflower, also contain beneficial fats and moderate amounts of polyphenols. When Guasch-Ferré and her colleagues swapped olive oil for these other vegetable oils in their hypothetical substitution model, they saw no increased benefit for brain health, suggesting that they too may offer health benefits.

“Consuming other vegetable oils could also be a healthy alternative compared to animal fat, especially since they tend to be more affordable compared to olive oil,” he says, although he cautions that more evidence is needed to confirm these results.

For now, the easiest advice is to opt for the highest quality extra virgin olive oil you can afford. If not, replacing animal fats with other vegetable oils is still likely to be a step in the right direction for brain health. And if you want to be extra annoying, you can even pay attention to what bottle it’s stored in – light reduces the amount of polyphenols over timeaffecting subsequent health benefits, so darker bottles may be better.

I’m convinced enough to spend a few extra pounds on a quality bottle of extra virgin olive oil, not only for its excellent taste, but also for its excellent brain-boosting abilities.

topics:

• neuroscience /
• food and drink