Is Canola Oil Healthy or Harmful?
I receive so many questions about canola oil — weekly, sometimes even daily! Everything from: Is canola oil healthy? Is this a healthy cooking oil? Would you recommend avoiding nuts if they are roasted in canola oil?
What’s the Deal with Canola Oil?
Canola oil is commonly advertised as a healthy oil and is especially promoted as a healthy alternative to saturated fats such as coconut oil and butter. It also tops the list of the American Heart Association’s “better-for-you” cooking oils, a list that includes corn oil, olive oil, peanut oil, safflower oil, soybean oil and sunflower oil.
Like the American Heart Association, other leaders in the health industry such as Whole Foods appear to be canola oil supporters. Expeller pressed canola oil is a Whole Foods staple, commonly used in their prepared food section dishes and a variety of their 365 products such as their roasted & salted almonds, macadamia nuts and more. But does canola oil live up to the healthy claims that have been made by the health industry and is it a healthy alternative to saturated fats?
What is Canola Oil?
Canola was cultivated in the 1970’s by two Canadian scientists through traditional plant crossbreeding techniques. Since then, scientists have worked on a variety of different plant breeding strategies, which has led to a large canola oil market.
Whenever a food is created by scientists, it needs to be approved by the Food and Drug Administration (FDA) and added to the Generally Recognized as Safe (GRAS) list. This is a long list of foods that are not naturally occurring but are deemed safe for human consumption, based on the latest science available. Canola oil was added to this list in 1985. Since then, canola oil has become the third largest vegetable oil used, behind palm oil and soybean oil.
The Nutrition Profile of Canola Oil
According to canola oil manufacturers, the dietary fat profile of canola oil includes:
-7% Saturated Fats
-62% Monounsaturated Fats
-28% Polyunsaturated Fats (19% omega 6 fatty acids and 9% omega 3 fatty acids)
-3% Other Minor Fats (including trans fats)
Canola oil does have a high smoke point (468 to 475?F), which is why it is advertised as an ideal option for high-heat cooking. In addition, one variety of canola oil, high oleic acid canola oil (HOCO), was created by scientists to contain even higher levels of MUFA and lower levels of polyunsaturated fat (PUFA) and trans fats than traditional canola oil.
Why Does the Health Industry Trust Canola Oil?
Canola oil has been advertised as a healthy oil option because it is low in saturated fatty acids, high monounsaturated fat (MUFA) and contains some omega 3 fats. It also boasts a seemingly healthy omega-6 to omega-3 fatty acid ratio (2:1), which is lower than other vegetable oils. Because saturated fats have been vilified for the past 40 years, there is a belief that foods high in saturated fats like butter = unhealthy and foods low in saturated fats (even if they aren’t technically whole foods, in the case of canola oil) = healthy. Read more about saturated fats here.
It is true, eating a diet that is low in saturated fats is associated with lower risk of high cholesterol levels. Research demonstrates that replacing saturated fats with canola oil is associated with lower levels of cholesterol, which is why the health industry has touted it as a healthy oil. This is likely why canola oil seems to be generally favorable when it comes to the research that has been conducted on improving various lipid levels.
However, it’s important to note many of the studies around canola oil are funded by groups who are leaders in the canola oil industry.
For example, one randomized double-blind, controlled feeding, crossover study, partially funded by the Canola Council of Canada and other canola oil industry groups, compared the effects of a diet containing canola oil and high oleic acid canola oil (HOCO) against a diet with a typical Western fatty acid profile in participants with metabolic syndrome risk factors. The results of this study showed the canola oil and HOCO participants had reduced total cholesterol and low-density lipoprotein cholesterol (LDL). The study indicated that both canola oil and HOCO are healthy substitutes for saturated fats and trans fats, related to the overall improvement in cardiovascular disease risk factors. Two limitations to this study were that the control group diet was twice as high in saturated fat intake and much lower in monounsaturated fats, compared to the canola oil diets.
In a 2013 review in Nutrition Reviews, the effect of canola oil consumption on cardiovascular disease risk factors, cancer, insulin sensitivity, glucose tolerance, and weight were reported. The effects of canola oil and HOCO on cardiovascular disease risk factors indicate some potential benefit, however the reviewed studies are admittedly flawed. When it comes to canola oil and cancer research, studies are ambiguous and there has also been a lack of consistent evidence supporting a benefit of using traditional canola oil to target weight, glucose levels and insulin production. Interestingly, the authors concluded that canola oil can be considered one of the healthiest edible oils with a variety of potential benefits. Of note, four of the authors are on, or receive funding from, the Canola Council of Canada.
Overlooked Concerns with Canola Oil
Despite being developed in the 1970s, it’s troubling that there has not been much independent research supporting the benefits of canola oil. Consumers may be surprised that many health experts and healthcare practitioners (in general) give the benefit of the doubt to products and say it’s safe until proven otherwise. This was the same stance that the United States took on cigarettes, Roundup and other chemicals, supplements and foods: they are safe until you can prove they are not. But by then, the damage may have been done.
Here are five key concerns with canola oil that are often overlooked.
1. The Process of Refining, Bleaching, & Deodorizing
The most commonly used vegetable oils in the United States (soybean, canola, palm and corn oil) fall under the umbrella of industrialized seed oils and/or RBD oils (refined, bleached, deodorized). RBD explains the processing that these oils undergo as they are manufactured. The processing involves crushing the plant to get the oil. The seeds portion called the “canola cake” is then washed with a solvent called Hexane, in a chemical extraction process.
Hexane is the most widely used solvent in the seed oil industry. Whether it is toxic for humans is still up for debate. Some reports, such as one from the Journal of Clinical and Experimental Toxicology, identify potential risks from short and long-term exposure to hexane, including polyneuropathy, muscle weakness, headaches, dizziness, and nausea. A report from the Environmental Protection Agency states that “neurotoxic effects have also been exhibited in rats. No information is available on the carcinogenic effects of hexane in humans and animals.” Many other experts argue that hexane is safe for human consumption, claiming there is very little evidence to demonstrate health risks associated with a low consumption of hexane. An expert from Harvard writes: “there appears to be very little reason for concern about the trace levels of hexane in canola oil.”
The next step of canola processing involves bleaching and deodorizing. The process of bleaching and deodorizing removes most of the hexane, making the level of ingestion very low. In one study, forty vegetable oils were assessed for residual hexane content and thirty-six of the forty did contain hexane, albeit at low, “allowable” levels. Whether you are comfortable with hexane being included in small levels in your foods is an individual choice. I recommend opting to keep as many chemicals out of the diet as possible. Your health is too important to take any chances with oils that are not 100% free of chemicals that demonstrate potential neurotoxic effects.
2. Trans Fats
The deodorizing process involves exposing canola oil to heat, about 200 C, under a vacuum. This is done for varying lengths of time, with the goal of removing compounds such as phospholipids. It converts some of the omega-3 and omega 6-fatty acids into trans fats. Trans fats are the group of fats that are being phased out of the food supply in artificial forms due to their clear association with heart disease. The trans fat content of canola oil varies between 0.3 to 3.3%. Margarine that is made from canola oil can contain even higher levels of trans fats. These trans fats are a byproduct of partial hydrogenation, which converts an oil – usually a vegetable oil – into a solid food such as margarine.
Many bottles of canola oil claim to contain zero trans fats on their front of package. This can happen if one serving or 1 tsp of canola oil contains less than 0.5g of trans fat. Labeling laws allow all companies to round down to 0g on the nutrition facts label if the product contains less than 0.5g. The tricky thing with trans fats is that you don’t need a large amount to increase risk of heart disease. And it’s not unlikely for a person to have four servings of canola oil–or 4 tsp–in one sitting, which may lead to consuming close to 2g of trans fats.
3. Genetically Modified Organisms (GMOs)
Most industrialized seed oils are genetically modified and canola oil is no exception. Genetically modified foods are created through recombinant DNA technology where the genes of different organisms are combined. The perceived benefits of genetically modified organisms (GMOs) are their herbicide and insect resistance, greater nutritional value, and ability to create larger crop yields and profits for producers. The first GMO plant was engineered in 1983 and in the mid to late 1990s, eight transgenic crops received marketing approval, with canola being one. Today in the United States, more than 90% of the canola oil produced is genetically modified for herbicide resistance.
Research demonstrating associations with poor health outcomes and GMOs include:
1-Food allergy risk: As reported in the Annals of Agricultural and Environmental Medicine, when plants are genetically modified, the expression and synthesis of new proteins occurs. If the sequence of those new proteins is the same as other known allergens, an undesirable immune response can occur with symptoms ranging from skin disturbance to anaphylaxis.
2-Toxicity: GMO’s have the potential to create toxic compounds and to create an environment in the body that initiates and encourages cancer growth. For example, in 1983, a modified rape oil was determined to be the cause of toxic oil syndrome, resulting in a number of fatalities in Spain. In addition, milk from genetically modified cows caused an elevation in insulin growth factor-1, which is a contributing factor in breast, colon, and lung cancers.
3-Herbicide resistance: During transgenesis, plants can be altered to become resistant to herbicides meant to destroy weeds. However it is possible, through hybridization, for new weed species to be created that are also resistant to anti-weed agents requiring much higher use of herbicides, which are potentially harmful to humans and also contaminate the water and soil.
4- Antibiotic resistance: Since bacteria are often used in the early stages of the GMO process, it is possible to transfer genes of resistance to the human microbiome creating less sensitivity to antibiotics aimed at pathogenic bacteria.
While the jury is still out on whether GMO’s are harmful, I recommend choosing not to be a human guinea pig with chemicals and genetically modified organisms in the food supply.
4. Omega 6 Fatty Acids
The primary fat in industrialized seed oils is linoleic acid, an omega-6 fatty acid. Omega 6 fatty acids are an essential fat but most people consume a large quantity, due in large part to the dependence on highly processed vegetable oils in the food supply. The typical American diet contains an abundance of omega-6 fats (an omega 6: omega 3 ratio of 15:1, on average). Since their introduction to the market, industrial seed oil consumption has altered tissue concentrations of the anti-inflammatory omega-3 fats eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in a negative way.
The omega 6 to omega 3 ratio of canola oil is approximately a 2:1 ratio. I will note, a 2:1 ratio is actually lower than most other industrialized seed oils like soybean oil, corn oil, cottonseed oil and sunflower oil. Many people falsely inflate canola oil’s omega 6 content. And while it is not on its own especially concerning, the abundant use of canola oil in the food supply, in addition to other vegetable oils, is a leading contributor to altered omega 6 to omega 3 ratios.
Consumption of omega-6 fats does not inherently promote inflammation and chronic disease but an imbalance in the omega-6 to omega-3 fatty acid ratio does support an inflammatory cascade in the body, increasing risk of chronic disease. As reported in Biomedicine & Pharmacotherapy, excessive omega-6 fatty acids in the diet, with deficiency of omega-3 fats may promote the development of inflammation, which is a root cause of most chronic diseases including cardiovascular disease, cancer, diabetes, and autoimmune disorders.
5. Concerns of Stability
Some of the appeal of saturated fats, such as coconut oil, is the high stability when it comes to high heat exposure. As nutrition expert, Dr. John Bagnulo, states: canola oil and industrially-produced oils are very high in polyunsaturated fats–omega 6s and omega 3s. This characteristic makes it highly unstable and susceptible to oxidation, which is a concern for cooking and food processing applications. In addition, these oils are less stable in the human body when they are incorporated into our mitochondrial and cell membranes. Since the oxidation of PUFAs is one driver of the inflammatory cascade that supports disease development in the body, it’s important to limit this type of fat.
If you choose to use canola oil, look for cold-pressed options, which have been shown to have more bioactive, health-promoting components than traditional processed canola oil, and avoid overheating the oil to help prevent oxidation.
Hidden Sources of Canola Oil in ‘Healthy’ Foods
There is no shortage of food companies that advertise themselves as healthy, gluten-free, all natural, and even organic but still contain canola oil. This is especially common at Whole Foods. It’s difficult to get through the entire store of Whole Foods without picking up several products that are made with canola oil or other industrialized seed oils. This is everything from their 365 food brand, including roasted nuts, pea crisps and tortillas, to their prepared food section that is covered in canola oil and other industrialized oils. All of their dressings are based in soybean oil.
Another example of canola oil hiding in seemingly healthy brands is popular oat milk brands like Oatly. The base of the milk is water, oats and rapeseed oil. Rapeseed oil is essentially the same thing as canola oil, as canola oil is made from the rapeseed plant.
When considering the entire picture of canola oil from creation to production to action in the body, it is not nearly as healthy as the health industry paints it to be. At the same time, when compared to other highly processed industrialized vegetable oils like soybean oil, canola oil may be a better option. But being better than other industrialized oils does not make it a desirable choice. While it does contain monounsaturated fats and omega 3 fats, you can get those same fat sources from whole food sources like extra virgin olive oil and wild salmon, respectively.
It’s difficult to argue that canola oil is not associated with improvements in cholesterol levels. At the same time, remember that the canola oil industry is a very profitable group that has a lot of influence on research studies, scientists and recommendations. As Dr. Bagnulo suggests, research regarding canola oil seems generally favorable when it comes to improving various lipid levels but using those over-simplified end-points does not tell the whole story when it comes to whole body health and overall risk of disease. This is why functional nutrition is so key–it helps look at the body holistically versus compartmentally like mainstream medicine.
The question that must be considered is: if a food product is able to decrease cholesterol levels in research, does that automatically deem it a health food? In the case of canola oil, do it’s cholesterol-lowering abilities outweigh the fact that it is not even a naturally occurring food to begin with? I don’t know the answers to these critical questions but until there is conclusive, independent evidence, I suggest leading with whole foods whenever possible.