Canola oil is a vegetable-based oil found in countless foods.
Many people have cut canola oil out of their diet due to concerns over its health effects and production methods.
However, you may still wonder whether it’s best to use or avoid canola oil.
This article tells you whether canola oil is good or bad for you.
Canola (Brassica napus L.) is an oilseed crop created through plant crossbreeding.
Scientists in Canada developed an edible version of the rapeseed plant, which — on its own — harbors toxic compounds called erucic acid and glucosinolates. The name “canola” comes from “Canada” and “ola,” denoting oil.
Although the canola plant looks identical to the rapeseed plant, it contains different nutrients and its oil is safe for human consumption.
Ever since the canola plant was created, plant breeders have developed many varieties that improved seed quality and led to a boom in canola oil manufacturing.
In fact, over 90% of the canola crops grown in the United States are GMO (2).
Canola crops are used to create canola oil and canola meal, which is commonly used as animal feed.
Canola oil can also be used as a fuel alternative to diesel and a component of items made with plasticizers, such as tires.
How Is It Made?
There are many steps in the canola oil manufacturing process.
According to the Canola Council of Canada, this process involves the following steps (3):
- Seed cleaning. Canola seeds are separated and cleaned to remove impurities such as plant stalks and dirt.
- Seed conditioning and flaking: Seeds are pre-heated to about 95℉ (35℃), then “flaked” by roller mills to rupture the cell wall of the seed.
- Seed cooking. The seed flakes are cooked by a series of steam-heated cookers. Typically, this heating process lasts 15–20 minutes at 176–221℉ (80°–105°C).
- Pressing. Next, the cooked canola seed flakes are pressed in a series of screw presses or expellers. This action removes 50–60% of the oil from the flakes, leaving the rest to be extracted by other means.
- Solvent extraction. The remaining seed flakes, containing 18–20% oil, are further broken down using a chemical called hexane to obtain the remainder of the oil.
- Desolventizing. The hexane is then stripped from the canola meal by heating it a third time at 203–239℉ (95–115°C) through steam exposure.
- Processing the oil. The extracted oil is refined by varying methods, such as steam distillation, exposure to phosphoric acid, and filtration through acid-activated clays.
In addition, canola oil made into margarine and shortening goes through hydrogenation, a further process in which molecules of hydrogen are pumped into the oil to change its chemical structure.
This process makes the oil solid at room temperature and extends shelf life but also creates artificial trans fats, which differ from the natural trans fats found in foods like dairy and meat products (4).
Summary Canola oil is a vegetable oil derived from the canola plant. Canola seed processing involves synthetic chemicals that help extract the oil.
Like most other oils, canola is not a good source of nutrients.
One tablespoon (15 ml) of canola oil delivers (6):
- Calories: 124
- Vitamin E: 12% of the Reference Daily Intake (RDI)
- Vitamin K: 12% of the RDI
Aside from vitamins E and K, canola oil is devoid of vitamins and minerals.
Fatty Acid Composition
Canola is often touted as one of the healthiest oils due to its low level of saturated fat.
Here is the fatty acid breakdown of canola oil (7):
- Saturated fat: 7%
- Monounsaturated fat: 64%
- Polyunsaturated fat: 28%
The polyunsaturated fats in canola oil include 21% linoleic acid — more commonly known as omega-6 fatty acid — and 11% alpha-linolenic acid (ALA), a type of omega-3 fatty acid derived from plant sources (8).
Many people, especially those following plant-based diets, depend on sources of ALA to boost levels of the omega-3 fats DHA and EPA, which are critical for heart and brain health.
Though your body can convert ALA into DHA and EPA, research shows that this process is highly inefficient. Still, ALA has some benefits of its own, as it may reduce fracture risk and protect against heart disease and type 2 diabetes (9, 10).
It’s important to note that the heating methods used during canola manufacturing, as well as high-heat cooking methods like frying, negatively impact polyunsaturated fats like ALA.
Additionally, during exposure to high temperatures during processing, a small amount of the oil’s unsaturated fats — especially its polyunsaturated fats — are turned into artificial trans fats, which further reduces the amount of omega-3s (11).
Artificial trans fats are harmful even in small amounts, prompting the World Health Organization (WHO) to call for global elimination of artificial trans fats in food by 2023 (12).
Summary Aside from vitamins E and K, canola oil is not a good source of nutrients. Canola oil may contain small amounts of trans fats, which is harmful to health.
Canola is the second-largest oil crop in the world. Its use in foods continues to expand (13).
As canola has become one of the most popular fat sources in the commercial food industry, concerns have grown over its health impact.
High in Omega-6 Fats
One downside of canola oil is its high omega-6 fat content.
Like omega-3 fats, omega-6 fats are essential to health and perform important functions in your body.
However, modern diets tend to be extremely high in omega-6s — found in many refined foods — and low in omega-3s from whole foods, causing an imbalance that leads to increased inflammation.
The omega-6 to omega-3 ratio of canola oil is 2:1, which may not seem particularly disproportionate (18).
Yet, because canola oil is found in so many foods and is higher in omega-6s than omega-3s, it’s thought to be a major source of dietary omega-6.
In order to create a more balanced ratio, you should replace processed foods rich in canola and other oils with natural, whole-food sources of omega-3, such as fatty fish.
GMO foods have had their genetic material engineered to introduce or eliminate certain qualities (19).
For example, high-demand crops, such as corn and canola, have been genetically engineered to be more resistant to herbicides and pests.
Although many scientists deem GMO foods safe, concerns abound over their potential impact on the environment, public health, crop contamination, property rights, and food safety.
While GMO foods have been approved for human consumption for decades, little data exists on their potential health risks, leading many people to avoid them.
Canola oil production involves high heat and exposure to chemicals.
Considered a chemically refined oil, canola goes through stages — such as bleaching and deodorizing — that involve chemical treatment (21).
In fact, refined oils — including canola, soy, corn, and palm oils — are known as refined, bleached, and deodorized (RBD) oils.
Although unrefined, cold-pressed canola oils do exist, most canola on the market is highly refined and lacks the antioxidants contained in unrefined oils like extra virgin olive oil.
Summary For the most part, canola oil is highly refined and GMO. It is also a rich source of omega-6 fats, which could contribute to inflammation if heavily consumed.
Although canola oil is one of the most widely used oils in the food industry, comparatively few long-term studies exist on its health impacts.
That said, some evidence suggests that canola oil may negatively impact health.
Several animal studies link canola oil to increased inflammation and oxidative stress.
Oxidative stress refers to an imbalance between harmful free radicals — which can cause inflammation — and antioxidants, which prevent or slow free radical damage.
In one study, rats fed a diet of 10% canola oil experienced decreases in several antioxidants and increases in “bad” LDL cholesterol levels, compared to rats fed soybean oil.
Plus, the canola oil diet significantly decreased lifespan and led to sizable increases in blood pressure (30).
Another recent rat study demonstrated that compounds formed during the heating of canola oil increased certain inflammatory markers (31).
Impact on Memory
Animal studies also indicate that canola oil may negatively impact memory.
A study in mice found that chronic exposure to a canola-rich diet resulted in significant harm to memory and substantial increases in body weight (32).
In a yearlong human study, 180 older adults were randomly assigned to either a control diet rich in refined oils — including canola — or a diet which replaced all refined oils with 20–30 ml of extra virgin olive oil per day.
Impact on Heart Health
While canola oil is promoted as a heart-healthy fat, some studies dispute this claim.
In a 2018 study, 2,071 adults reported how often they used specific types of fat for cooking.
Among overweight or obese participants, those who usually used canola oil for cooking were more likely to have metabolic syndrome than those who rarely or never used it (34).
Metabolic syndrome is a cluster of conditions — high blood sugar, excess belly fat, high blood pressure, and high cholesterol or triglyceride levels — which occur together, increasing your risk of heart disease.
The findings of the 2018 study contrasted with an industry-funded review that linked canola oil intake to beneficial effects on heart disease risk factors, such as total cholesterol and “bad” LDL cholesterol levels (25).
It’s important to note that many of the studies suggesting heart-health benefits for canola oil use less refined canola oil or unheated canola oil — not the refined type commonly used for high-heat cooking (35, 36, 37, 38, 39, 40).
What’s more, although many health organizations push to replace saturated fats with unsaturated vegetable oils like canola, it’s unclear if this is beneficial for heart health.
In one analysis in 458 men, those who replaced saturated fats with unsaturated vegetables oils had lower “bad” LDL cholesterol levels — but significantly higher rates of death, heart disease, and coronary artery disease than the control group (41).
Additionally, a recent review concluded that replacing saturated fats with vegetables oils is unlikely to reduce heart disease, death from heart disease, or overall mortality (42).
Summary Some studies suggest that canola oil may increase inflammation and negatively impact memory and heart health. However, more studies are needed.
It’s clear that more research is needed to fully understand how canola oil impacts health.
In the meantime, many other oils provide health benefits that are thoroughly backed by scientific evidence.
The following oils are heat-stable and can replace canola oil for various cooking methods, such as sautéing.
Keep in mind that saturated fats like coconut oil are the best choice when using high-heat cooking methods — such as frying — as they’re least prone to oxidation.
- Olive oil. Olive oil is rich in anti-inflammatory compounds, including polyphenol antioxidants, which may prevent heart disease and mental decline (45).
- Coconut oil. Coconut oil is one of the best oils for high-heat cooking and may help increase “good” HDL cholesterol (46).
- Avocado oil. Avocado oil is heat-resistant and contains carotenoid and polyphenol antioxidants, which may benefit heart health (47).
The following oils should be reserved for salad dressings and other uses that don’t involve heat:
- Flaxseed oil. Studies show that flaxseed oil may help reduce blood pressure and decrease inflammation (48).
- Walnut oil. Walnut oil has a rich, nutty taste and has been shown to reduce high blood sugar and cholesterol levels (49, 50).
- Hempseed oil. Hempseed oil is highly nutritious and has a nutty flavor perfect for topping salads (51).
Summary There are many effective replacements for canola oil. Heat-tolerant oils — such as coconut and olive oils — can be used for cooking, while flaxseed, walnut, and hempseed oils can be utilized in recipes that don't involve heat.
Canola oil is a seed oil widely used in cooking and food processing.
There are many conflicting and inconsistent findings in canola oil research.
While some studies link it to improved health, many suggest it causes inflammation and harms your memory and heart.
Until larger, better-quality studies are available, it may be best to choose oils that have been proven healthy — such as extra virgin olive oil — instead.