My mother loves canola oil while I have always been a bit suspicious of it. She likes the fact that it is low in saturated fat and high in heart-healthy monounsaturated fat — she uses a product that is half-butter and half-canola oil. She also likes the fact that, compared to butter, it is low in cost.
I won’t touch the stuff. Rumors that the golden liquid can be harmful to human health abound – but is there any scientific evidence that this stuff is really bad for us? I decided to check it and share my findings with you Dear Readers.
Much as I had secretly hoped to find a hidden scandal waiting for complete exposure, most experts agree that canola oil is perfectly safe.
This is good news since canola, a hybridized form of rapeseed, is the second-best seller of all common cooking oils, after soybean oil. A lot of people agree with my mom on this one.
Rapeseed (Brassica napus) is a yellow-flowering plant in the cabbage family. The blooms produce seed pods full of some 20 tiny round black or brownish-yellow seeds which are processed in a crushing facility to extract the oil before refining it to remove impurities and improve its taste.
Mechanically pressing the seeds squeezes out about 80% of the oil. This “first press” expeller oil may be refined further for use as a liquid oil, margarine or shortening.
Rapeseed is grown mainly in the prairie regions of western Canada. Some cultivation occurs in Ontario and the Pacific Northwest with small amounts grown in the midwestern and southeastern United States.
The finished product is called Canola oil, a protected name for this specific vegetable oilseed. “For an oil to be called Canola, it must meet an internationally regulated standard,” which is less than 2% erucic acid and less than 30 micromoles of glucosinolates.
Confusion arises, the experts say, because rapeseed oil contains very high levels of erucic acid, which in large amounts can poison humans. Studies conducted in the 1960s linked erucic acid in the body to myocardial lipidosis, an accumulation of lipids in heart muscle fibers that progressively damages and weakens muscle tissue.
In the early 1970s, Agriculture and Agri-Food Canada scientists at the University of Manitoba used standard cross-breeding methods to combine two rapeseed cultivars with the most desirable traits. Cultivar stands for “cultivated variety” and is a group of plants breeders select for their desirable characteristics to maintain during propagation (growing new plants) while selecting against undesirable traits.
The Canadian researchers produced a seed that was lower in both erucic acid and bitter-tasting glucosinolates. Canola – the name combines the first three letters of “Canada” and ola for “oil” – looks almost identical to rapeseed but is genetically a distinct plant with a new nutritional makeup that is different from its parent plant rapeseed.
That was a shrewd move because today the canola oil industry employs over 250,000 Canadians and adds $26.7 billion every year to the national economy.
One criticism opponents of canola oil have is that is has been genetically altered in the laboratory. About 80% of the canola grown in Canada is genetically modified to be resistant to herbicides. GM (genetically modified) foods are the subject of heated controversy around the world. The Canola Council of Canada seeks to calm these fears by pointing out that only one protein has been modified in the canola plant and this protein is removed during processing.
Here’s how canola oil breaks down nutritionally:
- 62% oleic acid, an omega-9 monounsaturated fatty acid (MUFA)
- 19% linoleic acid, an essential omega-6 polyunsaturated fatty acid (PUFA)
- 9% alpha-linolenic acid (ALA), a plant-based omega-3 PUFA
- About 7% saturated fatty acid (SFA)
Canola oil has the lowest SFA content of any common cooking oil — less than one-half the amount found in olive or soybean oils. Scientists have found no evidence that canola oil has the same cardiovascular health benefits as extra virgin olive oil – but canola, in moderate amounts, appears to be a harmless cooking oil.
Not all the news about canola is cheery, though. In 2017, researchers at the Lewis Katz School of Medicine at Temple University in Philadelphia, Pennsylvania, found that mice fed a diet rich in canola oil for 6 months had impaired working memory, weakened synaptic nerve firing, and gained weight.
In another study, rats put on a diet of 10% canola oil saw decreases in several antioxidants and increases in “bad” LDL cholesterol levels compared to rats fed soybean oil.
Other warnings about canola oil are that it depletes anti-inflammatory healing vitamin E, increases the risk of lung and heart cancers, shortens animal lifespans, and raises triglyceride levels a whopping 47%.
Also, canola is high in sulfur and spoils easily. Because it is odor-free and doesn’t taste bad when it turns rancid, the consumer may not know that the canola oil has gone bad. Rancid canola makes allergies worse and compounds lung or asthmatic problems.
My conclusion is that canola oil, like many other foods, has both benefits and risks. Like so many things in life, moderation is key.
Thanks to the popularity of this affordable butter substitute, we can expect to hear more expert opinions about the pros and cons of canola oil.