While many people know vegetable oil is unhealthy, people view canola oil a little differently.
Similar to olive oil, it enjoys a “heart healthy” public reputation.
But does canola deserve this moniker?
While some claim the oil is healthy because it’s low in saturated fat, others believe this doesn’t matter.
Many people in the nutrition field also criticize canola oil due to the harsh industrial production process it undergoes.
So, what is the truth? Is canola oil the same as vegetable oil? Or is it a healthier upgrade?
Let’s find out.
How is Canola Oil Made?
Just as crushed fresh olives produce olive oil, the commercial pressing of canola leaves us with canola oil.
But actually, that’s not true at all.
In fact, there is no such thing as a canola plant, and the ‘canola’ name is just a marketing acronym which stands for Canada ola.
In case you’re wondering; ‘ola’ apparently means oil (1).
As for the real manufacturing process, the seeds of a bright yellow plant called ‘rapeseed’ contain what will become canola oil.
However, to get oil out of a seed isn’t as simple as squeezing an olive or a coconut.
Therefore, a complex solvent extraction process is necessary, which involves the degumming, bleaching and deodorizing of rapeseeds.
The Canola Oil Production Process
If you have never seen the production of canola oil, then you can see the full process in this video:
Looks tasty, right?
- First, a filter system and magnets separate rapeseeds from any impurities. After this, the rapeseeds enter a screw press machine operating at high heat, which extracts 75% of their oil.
- As 25% of the oil is remaining in the rapeseed, the remainder of the crushed seed enters a chemical extraction process. This process involves a “washing” in a chemical solvent like hexane for 70 minutes to extract the leftover oil.
- Following the hexane wash, sodium hydrochloride further filters the oil to remove any leftover impurities. Next, the canola oil is bleached to lighten the (dark and murky) color.
- Finally, the oil goes through a “steam injection process” to remove the oil’s terrible odor.
Leftover Chemical Residues
However, even after this lengthy process the oil still contains trace amounts of hexane, which some people consider a health hazard.
The Canola industry argues that production removes virtually all of the solvents. But even so, many people don’t like the idea of consuming residues of toxic chemicals no matter what the dose.
Key Point: Overall, the production process of canola oil is complex and involves the use of chemical solvents. Despite claims of safety, many people feel even trace amounts of hexane are a health hazard.
A Brief History of Canola Oil
First released into the market in 1956/57, there were immediate safety concerns over canola oil due to the erucic acid content. Shortly after, the FDA recognized it as unsafe and banned it for human consumption (2).
Erucic acid is problematic for several reasons, and clinical studies link it to heart disease.
In order to navigate the ban, canola oil producers developed a new variety of rapeseed in the early 1970s. This new variety of rapeseed contained low levels of erucic acid and high levels of oleic acid (as seen in olive oil) (3).
Initially given the unmarketable name of “LEAR” (an acronym of low-erucic acid rapeseed,) this would soon become canola.
Canola Oil, Monsanto, and Glyphosate
Since that time, canola oil has changed further. The natural varieties of rapeseed were intolerant to glyphosate, a type of herbicide manufactured by Monsanto, a biotechnology giant.
With this in mind, Monsanto engineered a hybridization of rapeseed to tolerate glyphosate application in 1995 (4).
From this time to the present day, the vast majority of canola oil is from GM crops sprayed with glyphosate — 90% to be exact.
Key Point: Canola oil was initially banned, but underwent modification to lower the levels of erucic acid. Since the mid-1990s canola oil has also been produced from GM crops.
Is Canola Oil the Same as Vegetable Oil For Health?
While many people actively avoid cheap vegetable oil and know it’s damaging for health, they view canola as a ‘heart healthy’ oil.
So, is canola oil the same as vegetable oil? Or is there a difference between the two?
Firstly, vegetable oil can refer to many different oils, but the most prevalent one is soybean oil (5).
It’s also interesting to note that ‘vegetable’ oil doesn’t exist. The majority of ‘vegetable’ oils are grains (corn oil), beans (soybean oil) or seeds (canola oil).
Generally speaking, canola oil is better than most refined vegetable oils. However, I view it as the best of a bad bunch.
For the most part, this is down to the available studies. Looking for studies showing the adverse effects of soybean oil or corn oil is simple, as these oils have multiple links to a variety of health conditions.
In contrast, most of the studies on canola oil are relatively benign.
To clarify; I’m not saying canola oil is healthy, just that it’s a little better than other oils like soybean oil.
However, canola oil does have some concerning research behind it too — let’s take a look.
Animal Studies Show Harmful Effects of Erucic Acid
As has been noted, plant breeders produced a new low erucic acid variety of rapeseed to overcome the canola ban. However, there is a difference between low and zero.
Various animal studies show us that even low amounts of erucic acid may have negative health impacts.
In one study, eight groups of adult rats were separated and monitored for four weeks. All eight groups of rats fed on milk each day.
Two of these groups had their milk supplemented with erucic acid at either 0.5% or 5% concentration.
The data showed that the rats fed with erucic acid supplemented milk had the lowest survival rate.
The researchers pointed out that their study shows these negative effects in the 0.5% group, even though canola oil regulations allow a maximum of 2% erucic acid in the United States — four times this amount.
Further, the regulations allow for a 5% erucic acid concentration in the European Union (6).
Also, further animal studies show more dangers of erucic acid:
- Rats fed erucic acid show microscopic damage to the heart (7).
- Piglets fed low-dose erucic acid show lower platelet levels (8).
- Erucic acid-enriched diets show a decline in peak systolic pressure (9).
- Rapeseed oil causes renal toxicity in rats. In other words; kidney damage (10).
Key Point: Canola oil contains between 2% and 5% erucic acid (depending on where you live). Studies show that an equivalent amount or less reduces lifespan and causes damage to the heart and kidney in rodent studies.
Canola Oil is Not Safe For Cooking: Prone to Oxidation
As you may know, saturated fats are the most heat-stable source of fat. Second comes monounsaturated fat, and finally polyunsaturated fat — something which isn’t the best choice for cooking.
Regarding the fat content of canola oil, it comes in the following ratio (11):
- Saturated Fat: 7.1%
- Monounsaturated Fat: 64.3%
- Polyunsaturated Fat: 27.9%
As shown above, canola oil contains mainly unsaturated fat, and over one-quarter of the fat content is polyunsaturated omega 3 and 6. An older study also found that canola oil contains trans fat; an industrial source of fat that causes serious health concerns (12).
While you may have heard that omega-3 is good for you (which is true), it’s highly unstable when exposed to heat. In fact, all polyunsaturated fats are prone to oxidation when exposed to light and heat, and that certainly happens to canola oil a lot (13).
In the first place, there’s a lot of heat-related processing during production. Additionally, there’s the actual cooking in your kitchen.
The omega-3 to omega-6 ratio (2:1 for omega-6) of canola oil is also undesirable. While this isn’t hugely imbalanced compared to other oils, most people already eat far too much omega-6 without consuming even more from oil (14).
Key Point: The relatively high amounts of polyunsaturated fat in canola oil are unstable. In other words; high-heat cooking can damage canola oil.
Cooking at High Heat Releases Harmful Toxins
First of all, excessive heating of any oil can cause problems. However, different oils possess varying degrees of stability regarding heat.
On the negative side, cooking with oils also releases harmful cooking fumes.
Whether this is the smoke from olive oil or canola oil doesn’t matter; it will happen in any fat eventually, depending on temperature and length of cooking.
Studies show that even short-term exposure to cooking fumes can affect our health (15).
As these cooking fumes contain carcinogens, it’s important to choose a cooking fat carefully.
Canola Oil vs. Olive Oil: Which Releases the Most Toxins?
Aside from the obvious source material, the main difference between canola oil and olive oil is that canola is an industrially processed oil. On the other hand, olive oil is usually cold-pressed in a more natural production process.
Given canola oil and olive oil both earn praise as a “heart healthy” oil, let’s compare how they fare in a head-to-head challenge.
Interestingly, we can do this by looking at a study that compared the heat resistance of olive oil, extra virgin olive oil, and canola oil. Particularly important is that this was a controlled study which heated each oil at the same temperature for an equivalent time.
In brief, olive oil and extra virgin olive oil had a similar level of toxins in their cooking fumes. However, this was lower than the toxins in smoke from canola oil.
In other words; canola oil releases more harmful toxins than olive oil.
The researchers noted the importance of this by pointing out that people view canola as a frying oil but think of olive oil as a salad dressing (16).
A List of Fats To Substitute For Canola Oil
Provided that you focus on the more natural dietary fats when shopping, you won’t go far wrong. Some of the best fats to use for cooking include the following:
- Avocado oil
- Coconut oil
- Olive oil
- Palm oil (unrefined and ideally sustainably sourced)
For more information on which is the best cooking oil, take a look at this complete guide.
To sum up, canola oil probably isn’t as bad for you as other vegetable oils like soybean oil and corn oil.
However, there are several safety concerns around it, and it’s an ultra-processed, chemically extracted oil.
At the end of the day; why use canola when there are so many healthier oils out there?