canola oil, vegetable oil made from the pressed seeds of rapeseed (Brassica napus variety napus), a relative of turnips and cabbage in the mustard family.
Rapeseed oil has long been used in industry as a lubricant for engines and other machine parts, but, because of its high level of potentially harmful erucic acid, it was not considered safe for human consumption (though it was sometimes added to animal feed). It was not until the 1970s, when Canadian scientists developed a hybrid that contained a very low level of erucic acid, that experimentation began to place rapeseed oil among the vegetable oils available for use in cooking. Because of the unfortunate association of the element rape, which comes from the Latin word for “turnip,” with the criminal act, whose name comes from an unrelated Latin term meaning “to seize,” the company developing the hybrid brought it to market in 1979 under the name Canola, an acronym for Canadian oil, low acid. Outside of North America, however, it is usually sold as colza oil, which derives from the Dutch word for cabbage seed, or as rapeseed oil.
Widely licensed for manufacture, canola oil—its name now usually lowercase—is produced in many other places besides Canada, including Britain, China, and Pakistan. It is widely used as a cooking oil, valued for its neutral flavour. With a high smoking point (400 °F [204 °C]), canola oil lends itself to sautéing, frying, and baking, and it keeps well in storage.
Canola oil is considered safe for consumption not just because of its lowered erucic acid level, but also because it contains very little saturated fat and high levels of polyunsaturated omega-3 fat and phytosterols, which reduce the absorption of cholesterol in the body. Some health concerns have been voiced because of canola oil’s relatively high level of trans-fatty acids, which is comparable to walnut oil’s but approximately 10 times lower than soybean oil’s. The level of trans-fatty acids increases if the oil is not changed frequently in, say, a deep-fat fryer, but it will remain at the lower end of the scale in most home-cooking settings. In 2018 the U.S. Food and Drug Administration determined that canola oil may reduce the risk of coronary heart disease.