Using olive oil can 'boost' brain health, says new study

An estimated 5.8 million people in the U.S. have dementia, and those numbers are only expected to rise. With that, many people want to do what they can to lower the risk that they'll develop the debilitating disease over time. While dementia is a complicated condition that likely has several causes, a new study suggests a simple lifestyle change can help lower your risk of dying from dementia: incorporating olive oil into your diet.

What the study says

The study, which was conducted by researchers at Harvard University and presented at the American Society for Nutrition's Nutrition 2023 conference, found that those who used olive oil in place of condiments such as margarine and mayonnaise had a lowered risk of dying from dementia.

What are the key findings?

The study analyzed dietary and health data from 60,582 women and 31,801 men who didn't have cardiovascular disease and cancer at the start of the study, along with death records. Over a 28-year follow-up, 4,749 people died of dementia.

The researchers found that having more than 7 grams a day of olive oil (or about half a tablespoon) was linked with a 25% lowered risk of dying of dementia compared to people who never or rarely had olive oil. The scientists also discovered that swapping 1 teaspoon of margarine and mayo with the equivalent amount of olive oil a day was linked with an up to 14% lowered risk of dying of dementia.

"In U.S. adults, higher olive oil intake was associated with a moderately lower risk of fatal dementia, irrespective of diet quality," the researchers concluded. "Increasing olive oil intake in place of margarine and mayonnaise represents a potential strategy to reduce dementia mortality risk."

What experts think

It's important to note that the study didn't find that having olive oil alone actually lowers your risk of dying from dementia — instead, it found a link between people who have more olive oil and a lowered risk of dying from dementia. However, experts say there may be something to this.

"Olive oil is rich in antioxidant compounds such as polyphenols and vitamin E, which are known to combat oxidative stress," registered dietitian Scott Keatley, co-owner of Keatley Medical Nutrition Therapy, tells Yahoo Life. "Oxidative stress is a key factor in the pathogenesis of several neurodegenerative disorders, including Alzheimer's disease, which is the most common form of dementia. From this perspective, the study's findings make sense: Antioxidants in olive oil could potentially help protect the brain by reducing oxidative stress and inflammation."

Olive oil contains a lot of monounsaturated fatty acids, which are linked to cardiovascular health and brain health, registered dietitian Deborah Cohen, an associate professor in the department of clinical and preventive nutrition sciences at Rutgers School of Health Professions, tells Yahoo Life. "Vegetable oils — soy, sunflower, peanut — and margarine, on the other hand, contain primarily polyunsaturated fatty acids; butter and coconut oils contain more saturated fatty acids," she says.

"Some antioxidant compounds in olive oil can cross the blood-brain barrier, potentially having a direct effect on the brain," lead author of the study and registered dietitian Anne-Julie Tessier, a postdoctoral researcher at the Harvard T.H. Chan School of Public Health, tells Yahoo Life.

But experts caution against thinking that olive oil is the sole solution for preventing dementia. "It is hard to believe that one food product can influence overall brain health substantially," Dr. Amit Sachdev, medical director in the department of neurology at Michigan State University, tells Yahoo Life. "It is more likely that lifestyle and dietary choices make the difference."

However, Sachdev notes that diet does have a big impact on brain health, especially with blood vessel health in the brain. "Blood vessel problems lead to strokes and white matter changes, which can cause dementia symptoms," he explains.

Why it matters

Dementia is a complicated condition, and, as of now, there is no definitive treatment or method that researchers have discovered that can prevent it. "Dementia is a situation where memory, organization and emotional resilience aren't as robust as they used to be," Sachdev says. "The areas that govern these functions can be diminished for lots of different reasons."

While he and the other experts say that the findings don't mean everyone should suddenly start guzzling olive oil, Sachdev says there is a definite take-home message here. "A study like this emphasizes that simple switches in lifestyle can make a big difference in dementia risk," he says. What's actually driving that difference may not be the olive oil itself, "but rather being aware of your body and attempting to attend to it," he says.

Keatley agrees. "Replacing a saturated fat or a more processed fat source here and there with an extra virgin olive oil may help provide protection from oxidative stress that leads to diseases such as Alzheimer's," he says. "But, keep in mind that this is not the answer. It may be part of the solution to a very complex problem."

If you like olive oil and want to incorporate more of it into your diet, registered dietitian Jessica Cording, author of The Little Book of Game Changers, recommends being "pretty liberal" with its use. "When we look at studies on health impacts of olive oil, you'll very commonly see people have up to four tablespoons a day," she tells Yahoo Life. "I tell my clients to make olive oil their primary cooking oil, and their primary oil for dressings and garnishes."

Tessier also recommends swapping olive oil for more processed fats such as margarine and mayonnaise.

Keatley suggests looking at the latest study findings with "cautious optimism." He adds, "More research, particularly randomized controlled trials, are needed to further investigate this link and understand the exact mechanisms involved. It's exciting and valuable research, but there's still much we don't know about how olive oil might work to boost brain health and reduce dementia risk."

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