Canola oil — When a great oil isn’t so great after all

by Dr. Jospeh Mercola
Mercola.com

Warning: This oil comes with potentially damaging side effects due to either the ingredient it’s made from or the manufacturing process used to extract it. Because these negative effects overshadow the potential benefits, I do not recommend this oil for therapeutic use. Always be aware of the potential side effects of any herbal oil before using.

Canola oil is widely promoted as “one of the best oils for heart health.”¹ However, this information is rather flawed, as canola oil and similar highly processed cooking oils hold untold dangers to your health.

Read on to learn what you should know about canola oil, and what my personal recommendations for the best cooking oil are.

What is canola oil?

Referred to as “the healthiest cooking oil” by its makers, canola oil is low in saturated fats and high in monounsaturated fatty acids (MUFA) and polyunsaturated fats (PUFA) such as oleic acid, linoleic acid and alpha-linolenic (ALA).^2,³

The oil is produced from a series of processes ranging from solvent extraction with hexane, to refining, bleaching and deodorization.⁴

Although canola is a type of rapeseed, the canola you see on store shelves is not the rapeseed you may be familiar with that is used for industrial and nonedible purposes, such as for lubricants, plastics and hydraulic fluids.

The edible canola oil, on the other hand, is specifically grown as a food crop, genetically altered to contain significantly lower levels of erucic acid and glucosinolate in it, which makes it safe to eat.⁵

The modification focuses on broadening the seasons and regions where the plants can be cultivated and maximizing yield.

The bad news is that in order to boost the resistance, researchers have developed herbicide-tolerant canola, including Roundup-ready and Liberty-tolerant types.⁶

How is canola oil used?

Canola oil is a common ingredient in food products such as salad dressings, salad oil and margarines.⁷

Even though it’s marketed as a food product, according to the Canola Council of Canada, once plant-sourced oils like canola oil are processed they “can be used industrially to formulate lubricants, oils, fuels, soaps, paints, plastics, cosmetics or inks.”

Canola can also be used to produce ethanol and biodiesel. The point is, the Canola Council says, is that “just because you can do this doesn’t make the approved food oils at the grocery store somehow poisonous or harmful.”⁸

Composition of canola oil

Canola oil is often praised by the mainstream food industry due to its fatty acid content:⁹

Saturated fat — Canola oil contains about 7%, or about half the amount found in corn oil, olive oil and soybean oil.
Monounsaturated fatty acids (MUFA) — This is the most abundant fat in canola oil. The MUFA oleic acid makes up 61% of canola oil — second only to olive oil.
Polyunsaturated fatty acid (PUFA) — Compared to palm oil and olive oil, canola oil has a higher amount of PUFA. It has a ratio of omega-6 fat (linoleic acid) and omega-3 fat (alpha-linolenic acid) of 2-to-1.

How is canola oil made?

Unfortunately, details you’re told by vegetable oil manufacturers about canola oil’s production and benefits don’t tell the whole story.

As mentioned, canola oil was created through the hybridization and genetic alteration of the rapeseed, a plant used for industrial purposes.¹⁰ Rapeseed oil came from the plant known as “rape,” from a Latin word meaning “turnip.”¹¹

Along with cruciferous vegetables, rape is a domesticated crop belonging to the Brassicaceae family.¹²

Although rapeseed oil is composed of 60% monounsaturated fat, it is inedible because of two dangerous substances:

Erucic acid — a type of fatty acid that is associated with Keshan’s disease, characterized by fibrotic lesions in the heart¹³
Glucosinolates — bitter compounds that negatively affected the taste of rapeseed oil¹⁴

To turn rapeseed oil into an edible product, Canadian manufacturers used selective breeding to formulate seeds that had lower levels of erucic acid and glucosinolates. Canola oil, also known as “low erucic acid rapeseed (LEAR),” was formed.¹⁵

But, what the manufacturers don’t call attention to when they’re calling canola “healthy” is that hexane, one of the chemicals needed to extract oil from the seeds, is an HAP: a hazardous air pollutant. This begs the question of whether hexane is safe when ingested.¹⁶

According to the Toxicology Data Network, hexane may target the central nervous system and respiratory system when ingested.¹⁷ While hexane occurs in canola oil in only minute amounts, there are no sufficient studies that prove that it is safe to ingest.

Another part of the processing of canola oil is deodorizing, which is the step responsible for its bland taste. The bad news with this is that deodorizing reduces canola oil’s omega-3 fatty acids by up to 20%¹⁸ — so in the end, there’s not enough omega-3s for you to reap the benefits.

Is canola oil safe?

Although the food industry says it is, I do not believe canola oil is safe. Despite its “generally recognized as safe” (GRAS) status, no long-term human safety studies have been conducted on canola oil.¹⁹

Animal studies, however, contradict some of the health claims about canola oil.

For example, in Canadian research published in 1997 in Nutrition Research, piglets fed with milk replacers containing canola oil had signs of vitamin E deficiency, even if the replacement contained sufficient amounts of the nutrient.

Deficiency in vitamin E can be dangerous, as it can lead to free radical damage and cardiovascular problems.²⁰

A year later, researchers found the piglets fed with canola oil had reduced platelet count and an increase in platelet size. The researchers concluded that the ingestion of canola oil interfered with normal hematological development.²¹

In another animal test conducted, rats ended up with high blood pressure, an increased risk for stroke and a shortened lifespan when canola oil became their primary source of fat.²²

It is important to take note that these studies were made prior to the introduction of GE canola oil. This means you face not only the dangers of canola oil discovered in these studies, but also the potential hazards of genetically modified vegetable oils that may remain as residues in the final product.

Side effects of canola oil

So, what really happens when you use canola oil in your food?

The answer is that canola oil and other heated vegetable oils are some of the worst ingredients you can add to your food, if for no other reason that eating foods with canola oil will only distort your omega-6 to omega-3 ratio.

The bottom line is if you’re using canola oil, it’s time to throw it out and replace it with fats that will truly benefit your health.

One of your best options is coconut oil, which I personally use. Olive oil is also good, but if you’re going to cook with an oil, coconut is the better choice because it tolerates higher heat levels, as I explain later in this section.

Another problem with canola oil is that it’s even more dangerous when hydrogenated, which is common in processed foods. Manufacturers hydrogenate the oil because it prolongs processed foods’ shelf life.²³

And then, to make matters worse, consuming these foods exposes you to even higher levels of trans fats.²⁴

So, the idea that canola oil is beneficial to your health is nothing but a myth.

Another myth is that saturated fat is bad for you. The “bad” fat belief stemmed from Ancel Keys’ Seven Countries Study,²⁵which linked saturated fat with heart disease.

The truth is that his research was manipulated to achieve the conclusion that saturated fat is “bad,” as he selectively analyzed data from seven countries rather than comparing all data from 22 studies available to him at the time.

When you look at the majority of the data he had available to him, you’ll find that all the data combined actually disproved his theory. The truth is saturated fat does not cause heart disease and is, in fact, an important part of a healthy diet.²⁶

The reason coconut oil is the best choice for cooking is that it’s resistant to heat damage, unlike canola oil and other vegetable oils.

Coconut oil also carries beneficial fat like lauric acid, which provides antiviral, antibacterial and antiprotozoa properties.²⁷

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