Here’s an interesting dietary finding that doesn’t require buying a superfood.
In a large long-term study, people who consumed more olive oil had a lower rate of dementia-related death.
The study included 92,383 adults from the Nurses’ Health Study and Health Professionals Follow-Up Study and followed them for up to 28 years.
People consuming more than about 7 grams of olive oil per day had a 28% lower risk of dementia-related death compared with people who rarely or never consumed olive oil.
Researchers also looked at what happened when olive oil replaced other fats.
Replacing 5 grams per day of margarine or mayonnaise with olive oil was associated with a lower risk as well.
Sounds pretty impressive.
But here’s where the story gets interesting.
Association isn’t prevention
This was an observational study.
Nobody was randomly assigned to eat olive oil.
People who eat more olive oil may differ from people who don’t in many other ways.
They may eat more vegetables.
Exercise more.
Smoke less.
Follow a Mediterranean-style diet.
Or simply have other characteristics that weren’t completely captured by the statistical adjustments.
So the study does not prove that olive oil prevents dementia.
It found an association between olive-oil consumption and lower dementia-related mortality.
That’s still worth knowing.
Why olive oil?
Extra-virgin olive oil contains monounsaturated fats and a variety of bioactive compounds, including polyphenols.
Those compounds are one reason olive oil is a central part of Mediterranean-style eating patterns.
But we shouldn’t jump from that biological plausibility to a claim that olive oil is a dementia treatment.
The research doesn’t support that.
The useful part may be the substitution
The most practical takeaway isn’t necessarily:
“Start taking a shot of olive oil every morning.”
It’s simpler.
If you’re regularly using butter, margarine or mayonnaise, consider whether some of those calories could instead come from olive oil.
That’s a dietary substitution—not an extra supplement.
And that distinction matters.
A small change, not a magic food
No single food determines whether someone develops dementia.
Your overall dietary pattern, physical activity, cardiovascular health, sleep, social engagement and genetics all matter.
But replacing some less favorable fats with olive oil is a reasonable dietary experiment, particularly if you already enjoy it.
Evidence & Source
Evidence: Moderate. The study was exceptionally large and followed participants for decades, but it was observational and relied partly on self-reported dietary intake.
Source: Read the study (JAMA Network Open)(opens in a new tab)