Canola oil has been called both the “world’s healthiest cooking oil” and a “poison.” Obviously there is much misunderstanding and misinformation out there about it. The oil comes from a specially bred variety of rapeseed, a yellow-flowering plant in the Brassicaceae (cabbage) family, developed by Canadian scientists in the 1970s. Its name is a contraction of Canadian and ola (meaning oil).
Is canola oil “toxic,” as many people warn?
No. The confusion involves erucic acid, a substance in traditional rapeseed that has been linked with structural changes in heart tissues and other problems in animals. But canola has been specifically bred to be very low in erucic acid. In 1981, several hundred deaths in Spain were linked to food-grade rapeseed oil—but it turned out the oil (mislabeled as “olive oil”) was contaminated with an industrial solvent that was being used illegally.
Despite the long-standing safety of canola oil, the Internet is still awash with rumors that it causes all kinds of maladies. There has never been any evidence to support these claims. According to the EPA, canola oil’s “toxicological profiles are similar to those of other vegetable oils that are used as food.”
Isn’t canola oil used industrially?
Yes, though that doesn’t mean it’s dangerous to consume. Canola oil can be used, for example, as a pesticide (it smothers insects), industrial lubricant, and biofuel—but that’s true of any vegetable oil. It’s also used to make soaps, plastics, cosmetics, and printing inks. In fact, such uses are generally considered environmentally friendly alternatives.
How does canola compare to other oils nutritionally?
All vegetable oils contain a mix of polyunsaturated, monounsaturated, and saturated fatty acids. Canola oil consists mostly of monounsaturated fats (61 percent, almost as much as olive oil) and polyunsaturated fats (32 percent). Of all vegetable oils, it is lowest in saturated fats (7 percent). And, notably, it is second highest in alpha-linolenic acid (ALA), an omega-3 polyunsaturated fat related to the omega-3s in fish (11 percent ALA, compared to 57 percent in flaxseed oil). In contrast, olive, corn, safflower, and sunflower oils contain just 1 percent ALA.
Like many other plant foods, canola oil contains phytosterols (such as beta-sitosterol), which lower cholesterol, along with some vitamin E and K.
What are canola’s health benefits?
Twenty years ago, the well-known Lyon Diet Heart Study from France, which put the “Mediterranean diet” on the map, found that an ALA-rich diet (with fats coming largely from canola oil-based margarine) significantly reduced heart attacks and deaths in people who had a prior heart attack.
Several studies since then have also shown that canola oil, when substituted for saturated fats, has heart benefits. For example, in a small study in the Journal of Internal Medicine in 2011, a high canola oil diet (from a spread) lowered LDL (“bad”) cholesterol and triglycerides in people with high cholesterol after three weeks. And a review of 40 studies in Nutrition Reviews in 2013 linked canola-based diets to reduced LDL oxidation (oxidation makes LDL more harmful) and decreased blood clotting, compared to saturated-fat-based diets.
Other vegetable oils have similar effects, however, and it’s not clear how canola oil compares with them. Still, some researchers contend that canola oil may be advantageous because of its higher ALA content.
Since 2006, the FDA has allowed canola oil and products containing it to carry this qualified health claim: “Limited and not conclusive scientific evidence suggests that eating about 1.5 tablespoons (19 grams) of canola oil daily may reduce the risk of coronary heart disease due to the unsaturated fat content in canola oil. To achieve this possible benefit, canola oil is to replace a similar amount of saturated fat and not increase the total number of calories you eat in a day.”
What is high-oleic canola oil?
Used in commercial food production, high-oleic canola oil is higher in monounsaturated fats (oleic acid is monounsaturated) than regular canola oil, though it is also lower in ALA. The food industry likes it because it is more heat-stable, so it lasts longer in frying (it has a high “fry life”), and it is less susceptible to developing off-flavors. Also important, it is a good substitute for partially hydrogenated oils.
Is all canola genetically modified?
Nowadays most, but not all, canola plants in North America are genetically modified to be resistant to the herbicide RoundUp, used for weed control. But the original canola plant was developed through traditional plant-breeding methods (genetic engineering didn’t even exist at the time). In any case, the oil, whether from a genetically modified or conventional canola plant, is the same. Organic canola oil, by definition, cannot be produced from genetically modified plants—though it makes up only a small percent of the market. In Europe, canola oil is produced from non-modified plants only.
What about claims that canola oil is extracted using toxic chemicals?
To produce canola (and other vegetable) oils, the plant’s seeds are crushed and then typically heated and subjected to chemical solvents, like hexane, to extract the oil. Manufacturers claim that virtually all the solvent is then removed, but it’s unclear whether trace residues might be a health hazard; hexane also has adverse environmental effects. Cold- and expeller-pressed oils, including canola, do not involve the use of chemical solvents and, because they undergo less processing, tend to be higher in nutrients and antioxidants. They also cost more.
Bottom line: Like other healthful vegetable oils, canola oil can be used in place of butter or shortening in all types of cooking, including baking and sautéing, as well as in salad dressings and marinades. If you’re concerned about hexane processing or just want to be more environmentally friendly, look for cold- and expeller-pressed oil. If you want to discourage the use of genetic modification, buy organic or European-produced oils. Keep in mind that all oils—including canola—are calorie-dense, with about 120 calories per tablespoon.