There are all sorts of rumors about canola oil—so let’s sort fact from fiction.
First, you may have heard that canola oil contains high levels of the toxic compound erucic acid. Not true. “The rapeseed plant that canola oil was originally derived from does contain high levels of erucic acid, but it’s been bred out of the canola plant we get our oil from today, so levels are very low and not harmful—the FDA regulates how much is allowed (no more than 2 percent),” says Libby Mills, R.D.N., a spokesperson for the Academy of Nutrition and Dietetics. In the late 1960s, traditional plant breeding methods—not biotechnology—were used to rid rapeseed of its undesirable qualities and canola was born. Today most of our canola oil is genetically modified, which adds a certain creep factor for some people. Truth is, there’s no hard evidence that genetically modified foods like canola oil cause adverse health effects in humans, but there’s also no good research proving that they don’t. The FDA doesn’t independently test GMOs; rather, they rely on reports from the manufacturer when clearing them for public consumption. So if you’re concerned about GMOs, buy organic.
Then there’s the claim that canola oil is processed using dangerous chemicals. There’s a kernel of truth here. Canola—like many oils—is extracted using hexane, which is dangerous (it’s flammable). That said, the final oil is essentially hexane-free—and there’s no solid evidence to suggest this method of processing is bad for your health.
There is also some truth to the idea that cooking with canola can be toxic. But there’s no need to rid your pantry of it. When canola oil is heated to high temperatures (think: frying), especially for a long time, linoleic acid (a healthy fatty acid also in corn, safflower and soybean oils) gets broken down into a compound called HNE, which has been linked to heart and liver disease and neurological problems. HNE becomes particularly concentrated when canola oil hits its smoke point or is reheated. “There’s no research on what amount of HNE is harmful, but it’s prevalent in packaged and restaurant foods—especially fried foods,” says Mills.
The temperature at which an oil begins to smoke. It varies with each oil, but in general the more refined the oil, the higher the smoke point. Heating an oil to its smoke point destroys beneficial compounds and creates harmful free radicals.