Canola Oil

A challenge of living in the Information Age is learning how to distinguish good reporting from bad. While the Internet has granted access to unprecedented stores of knowledge, it has at the same time blurred the line between fact and fiction, as fanciful claims travel through cyberspace alongside credible contention. Few issues illustrate this point as well as the “controversy” over canola oil. While some of canola’s criticisms deserve consideration, the majority of accusations against it are, quite simply, balderdash. But before we decipher canola’s pros and cons, a little history is in order.

What’s a Canola?

The story of canola starts with a pungent plant of the mustard family known as rape. The oil of the rape plant’s seeds, or rapeseed oil, has been used for cooking in India and China for centuries. It was also common in Canadian kitchens during the 50s and 60s before a study reported that one of rapeseed oil’s main fatty acids, the monounsaturated erucic acid, caused health problems in rats.1 Since rapeseed had become a cash crop in Canada, where it grows well in the subarctic conditions, the hunt was on there to breed a version of rape void of the troublesome fatty acid. The result was a selectively-bred rape plant that contains very little erucic acid. At first the plant’s oil was marketed as Low Erucic Acid Rapeseed (LEAR) oil, but later the name was changed to the catchier “canola,” a contraction of “Canada” and the oily-sounding “ola.”2 Although “canola” technically refers to the oil of the rape hybrid, the term has been around for so long now that it is used to refer to the plant as well.

Canola Oil is Not Rapeseed Oil

Although canola oil comes from a plant derived from rape, it’s important to note that canola oil and rapeseed oil are two different beasts. This distinction is lost on many a website, where “canola” and “rapeseed” are often used interchangeably. One of the biggest differences between the two oils is that rapeseed oil contains up to 40% erucic acid, while canola oil contains virtually none of the stuff—less than 2% by law.3 In spite of this fact, many Internet writers condemn canola for its alleged erucic acid content. Whether erucic acid is harmful is now debated, but the argument is moot when discussing canola because there is virtually no erucic acid in canola oil.

Health Claims in Support of Canola

In place of erucic acid, canola was bred to contain about 60% oleic acid, the prized monounsaturated fatty acid of olive oil (which is about 70% oleic acid). In addition to being high in oleic acid and low in erucic acid, canola also contains little saturated fatty acid (7%) and a substantial amount of omega-3 polyunsaturated fatty acids (11%).4 Since a diet low in saturated fatty acids and high in monounsaturated and omega-3 fatty acids is believed by many researchers to be beneficial for cardiovascular health, promoters of canola oil often tout it as the “healthiest vegetable oil.”5 Combine the oil’s favored fatty acid profile with a long shelf life and low cost, and you have a happy confluence of interests between mainstream science and the food manufacturing industry, which uses canola in everything from mayonnaise to granola bars.

Criticisms of Canola

Not everyone agrees that canola is the healthiest vegetable oil out there. For one, because crude canola has an off-putting taste, it is deodorized as part of an overall refining process that removes or destroys many nutritious compounds in the raw oil, such as minerals and antioxidants.6 Canola’s backers are quick to add that most other seed oils, such as sunflower and safflower oils, are also refined, but this does not change the fact that refined canola is a processed, un-whole food. It is also important to note that the majority of canola grown in the United States is genetically modified. Genetically-modified foods have never been tested for safety. Always choose organic canola oil, as USDA organic standards do not allow any genetically-modified organisms.

In addition to this reasonable questioning of canola’s healthfulness, the Internet is plastered with accusations against the oil that range from outlandish to absurd. While the criticisms can be found on any number of sites, almost all of them can be traced back to a single article titled “Blindness, Mad Cow Disease, and Canola Oil,” by a man named John Thomas. The article reputedly appeared in the March/April 1996 issue of Perceptions magazine, and it has been reproduced on countless websites.7 Below we address some of the report’s chief contentions.

Canola is an “industrial oil” unfit for human consumption.

More chicanery: any edible oil can be denatured and processed for use as an industrial chemical, and many are. Popular oils for industrial use include flax oil, which is used in paint, ink, cosmetics and linoleum, and coconut oil, a main ingredient in many soaps and cosmetics.10

Canola oil is a hydrogenated oil full of trans fatty acids.

Any seed or vegetable oil can be hydrogenated, a process that generally leads to the formation of trans fats. Oils are hydrogenated to make them more fat-like, i.e., solid instead of liquid at room temperature. So, liquid bottled canola oil is not hydrogenated. If you are worried about hydrogenated canola oil in a packaged food, just look at the ingredient list. Any product that contains hydrogenated or partially hydrogenated oil must state this fact; it also must list the amount of trans fats in its Nutrition Facts. (Though beware that, according to FDA guidelines, a food containing any amount of trans fats less than 0.5 g per serving can state that it contains 0 g trans fat on its label.) Regarding liquid seed and vegetable oils, some researchers claim that the high heats of refining morph the oil’s unsaturated fats into trans fats.11,12 Others claim that the fatty acid profile of a refined oil remains essentially unchanged.13 In any case, if trans fats are formed, the amount created is in all likelihood minimal, as evidenced by the fact that the Nutrition Facts on most seed and vegetable oils list the trans fat content as 0 grams.

The Canadian government acquired the needed FDA GRAS (generally recognized as safe) status needed for LEAR (canola) oil to enter the U.S. food supply without any of the normally required testing and research.

Here Mr. Thomas seems to have confused the approval procedure of a drug with that of a food seeking GRAS status. While the former is a mandatory, regimented process that involves years of testing and research, gaining GRAS for a food is far less formal or rigorous, requiring for approval only the general agreement among scientists that a food is safe to consume. Moreover, a food doesn’t technically need to gain GRAS status to be brought to market. (Generally, the FDA gets involved only if a food on the market causes a public health crisis.) In the case of canola, the Canadian government seems to have sought GRAS for its new oil to distinguish canola from rapeseed oil, which some experts considered unsafe at the time (though it was being consumed in countries such as Great Britain, France, and Germany). To obtain GRAS for canola, the Canadian government submitted, in 1985, a lengthy petition to the FDA, citing over 60 peer-reviewed studies regarding the relative safety of LEAR oil in both animals and humans. In conclusion of its 59-page, point-by-point response to the petition, the FDA states plainly, “LEAR oil can be affirmed as GRAS based on…a large body of scientific data…published in the scientific literature.” In fact, in reviewing the Canadian petition, the FDA states that it examined over 200 published studies in all.14

Rapeseed oil causes Mad Cow’s disease.

In addition to incorrectly equating rapeseed oil with canola oil, Thomas implies that rapeseed meal fed to European cows was somehow responsible for the outbreak of Mad Cow Disease (bovine spongiform encephalopathy, or BSE) in the 1990s. While the cause of BSE has yet to be clearly identified, conventional theory attributes the outbreak to an infectious form of protein called a prion present in the sheep offal fed to the fated cows.15 A competing theory maintains that organophosphate insecticides caused malformation of the cow’s natural prions.16 In any case, no evidence that rapeseed oil was responsible in any way for the outbreak has ever been published.

Rapeseed oil is the source of mustard gas.

Rapeseed is a member of the mustard family (Brassicaceae), which also includes cabbage, cauliflower, broccoli and mustard seed.17 Apparently, mutual use of the word mustard was sufficient cause for Thomas to propose that rape oil is the source of the chemical agent mustard gas. In truth, mustard gas derives its name not from any connection with mustard plants but from its caustic odor, which is reminiscent of, you guessed it, mustard. The chemical name of mustard gas is 2,2′-dichlorodiethyl sulfide, and it is prepared from the chemicals ethylene and sulfur chloride, not rapeseed oil, which consists primarily of organic fatty acids.18

In addition to the claims above, Thomas attributes a slew of ill effects to canola or rapeseed oil, including glaucoma, blindness, emphysema, respiratory distress, anemia, constipation, and irritability. According to Thomas, canola also antagonizes the central and peripheral nervous systems and delivers cyanide-containing compounds into the body that inhibit the production of the body’s energy molecule, ATP. Unfortunately, none of this is backed up with any sort of proof. While there is always the possibility of idiosyncratic reactions to any food, to the best of our knowledge none of the effects cited by Mr. Thomas have been documented or supported by scientific research.

Should You Eat Canola?

Mad cows and mustard gas aside, perhaps you just want to know whether you should eat canola. That really depends on what you’re looking for in an edible oil. If you eat a lot of processed foods such as salad dressings, crackers, cookies, and chips, then canola and its superior fatty acid profile are probably a better choice than most of the other fats found in such foods—especially corn, soy, peanut, and cotton seed oils. (This assumes, of course that the canola has not been hydrogenated. Hydrogenated oils of any sort are toxic and should be avoided.) Canola is also useful if you want to bake or cook with a fat that will impart no taste to your food and has a good shelf life. But at the same time remember that canola is a refined food, stripped of many intangibles that a healthful “whole” cooking fat such as extra virgin olive oil provides. In the end, perhaps it is best to think of canola as a kind of a nutritionally neutral food, a “cleaner” choice than other refined seed and vegetable oils but not quite at the health-promoting level of unprocessed fats such as organic butter, extra virgin olive oil, and virgin coconut oil.


  1. Erasmus U, Fats That Heal, Fats That Kill (Burnaby: Alive Books, 1993), 116–117.
  2. Personal correspondence with Dr. Keith Downey, Canadian agricultural chemist who helped breed the low-erucic rapeseed plant that produces canola oil.
  3. “Growing Canola,” Canola Council of Canada website, 2005 (5 June 2007), <>.
  4. “Canola Oil Properties and Uses,” Canola Council of Canada website, (4 June 2007), <>.
  5. Coleman B, The Canola Journal (Sept 2003): 3.
  6. Erasmus, 93–99.
  7. Thomas J, “Blindness, Mad Cow Disease, and Canola Oil,” (3 June 2007), <>.
  8. “Genetically Modified Foods: A Primer,” CBC News Online, 11 May 2004 (6 June 2007), <>.
  9. “Genetically Modified Crops in the United States,” Pew Initiative on Food and Biotechnology website: Factsheet, 2007 (6 June 2007), <>.
  10. Enig M, “Dangers of Canola,” Dr. Joseph Mercola’s eHealthy News You Can Use, 16 January 2000 (4 June 2007), <>.
  11. Erasmus, 96–97.
  12. Enig, “Dangers of Canola.”
  13. “The Truth About Canola Oil,” Spectrum Organic Products, Inc. (2001).
  14. “Direct Food Substances Affirmed As Generally Safe: Low Erucic Acid Rapesed Oil,” U.S. Food and Drug Administration website: 21 CFR Part 184, 1 April 2001 (6 June 2007), <>.
  15. “Commonly Asked Questions About BSE in Products Regulated by FDA’s Center for Food Safety and Applied Nutrition (CFSAN),” U.S. Food and Drug Administration website, 14 Sept 2005 (6 June 2007), <>.
  16. Purdey M, “Animal Pharm,” The Weston A. Price Foundation website, Fall 2000 (6 June 2007), <>.
  17. USDA Natural Resources Conservation Service website: Plants Database (6 June 2007) <>.
  18. Enig, “Dangers of Canola.”