News & Blog

Fiftysomething Diet: Is Canola Oil Safe?

Sorting out myth from truth about 4 scary rumors

By Maureen Callahan for Next Avenue

The American Heart Association recommends cooking with oils like canola because they are rich in heart-healthy monounsaturated fats, the kind that don't clog arteries. Home cooks prize canola oil for its neutral flavor, making it a versatile choice for everything from baking to pan frying.

Yet, this supposedly heart-healthy oil continues to be dogged with concerns about safety.

Are these just wild Internet rumors or are there real toxicity concerns with canola oil, things that might sabotage a fiftysomething's attempts to eat healthy?

Here we take a look at what critics lay out as four major negatives of canola oil, and then stack them up against current scientific findings:

1. Canola oil is harvested from a toxic plant and contains toxins.

The canola plant was developed through crossbreeding with the rapeseed plant and this, it seems, is where the confusion about toxins originates. One plant is harmful to humans; the other is not.

"Rapeseed oil contains very high levels of erucic acid, a compound that in large amounts can be toxic to humans. Canola oil, however, contains very low levels of erucic acid," explains Mayo Clinic dietitian Katherine Zeratsky.

Bottom line: Neither the canola plant, nor canola oil, contains toxins.

2. Canola oil is processed with dangerous chemicals.

The most common method for harvesting oil from the canola plant involves crushing its seeds and then extracting any last bits of remaining oil with hexane, a low-boiling solvent.

"Hexane has been used to extract oils from plant material since the 1930s, and there is no evidence to substantiate any risk or danger to consumer health when foods containing trace residual concentrations of hexane are ingested," says Guy Crosby, an adjunct professor of nutrition at the Harvard School of Public Health. (Interestingly, all of the top four vegetable oils — soybean, canola, palm and corn oil — are manufactured this same way.)

However, there is an alternative extraction process that involves crushing the seeds without a solvent or heat, in effect cold-pressing them at a slow pace in order to let friction help extract the oil. These expeller-pressed oils typically cost more and pack stronger flavors.

Bottom line: While scientists consider the trace levels of hexane that remain in canola oil after processing to be of little concern, it's possible to purchase oils processed without solvents. Look for labels that say organic or expeller-pressed and expect to pay a little bit more.

3. Canola oil is genetically modified.

Complicated. That's the best word to illustrate the difficulties of untangling the pros and cons of genetically-modified food crops like canola, soy and corn, a discussion that is far too involved for this short article. Some scientists swear that GMOs are safe. Others express concerns that the continued use and creation of GMOs creates health problems like allergies and other unknowns.

If you're not as familiar with the GMO controversy as you'd like to be, this Katie Couric video sums it up nicely.

Bottom line: GMOs are part of the food supply. If you want to avoid them, choose organic canola oil. It's illegal to use genetic engineering in the production of any organic food.

4. Canola oil contains harmful trans fats.

It is well established that both saturated fats and trans fats can raise levels of "bad" LDL cholesterol, the kind of fat that can clog arteries.

That's why the American Heart Association recommends cooking with liquid fats — oils like olive, canola and safflower. Dr. Dean Ornish, famous for his plan for reversing heart disease, thinks canola oil is an even better choice than olive oil since it "results in lower LDL cholesterol levels."

So then where do the trans fats come in? Well, that happens when canola oil is heated during processing. Heating converts teeny tiny amounts of the unsaturated fats, particularly the plant-based omega 3 fats like linolenic, to trans fats.

"Other vegetable oils, and even nut oils, have been found to contain levels of trans-fatty acids that are comparable to the levels in beef fat," says Crosby.

Bottom line: The amounts of trans fat in canola oils are too minimal to cause harm.

So in the end, this litany of negative strikes against canola oil is mostly smoke and mirrors clouding the issue that this oil — organic or regular — is both a safe and good choice for cooking.