Does canola oil cause dementia?

“Alzheimer’s symptoms worsened by canola oil—and it could cause onset of dementia, scientists warn,” ran Newsweek’s headline in December 2017.

Yikes. Time to toss your canola oil?

“I don’t know how that study was ever published,” says James Roede, a neuro­degenerative disease researcher and assistant professor of toxicology in the department of pharmaceutical sciences at the University of Colorado, Denver.

The study Newsweek was describing used six-month-old mice that were genetically engineered to have Alzheimer’s-like plaques in their brains. For six months, the mice got either a control or a “canola oil-enriched” diet—the equivalent of about a teaspoon of canola oil added to every 200 pounds of food.1 (That’s enriched?)

“Every part of the study design is flawed,” says Roede.

First, what happens in the brains of mice may not happen to people who get Alzheimer’s disease.

“Normal mice won’t develop plaques on their own, so this mouse model pushes the brain to produce amyloid with multiple copies of genes,” explains Roede. “It’s totally artificial.”

And while people with Alzheimer’s have plaques made of beta-​amyloid protein, “amyloid may be a marker, not a cause, of the disease,” notes Roede. “Studies that have targeted amyloid have failed to reverse symptoms.”

Second, the researchers didn’t report how much food the mice ate or what was in the control diet. Worse yet, “if you look at the data, barely anything was statistically significant,” says Roede.

In 35 of the roughly 40 markers and tests of brain health that the researchers looked at, canola oil had no impact at all.

One, the Morris water maze, “is a great test for assessing learning and memory,” says Roede. “And they saw no difference with canola oil.”

As for the five statistically significant differences: they could have been due to chance.

The Bottom Line: The evidence that canola oil causes Alzheimer’s? Zilch.


1 Sci. Rep. 7: 17134, 2017.

Photo:  Jolene Mafnas/CSPI.

The information in this post first appeared in the June 2018 issue of Nutrition Action Healthletter

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