Canola oil contains trans fats, inflammatory omega-6 fats, and free radicals that increase the risk for mental health problems. Learn how to avoid it.
Canola oil is the third most popular vegetable oil in the world. (1)
You’ll find it in fast food, restaurant food, and processed foods of all kinds sold in both mainstream supermarkets and health food stores.
It’s widely touted as a healthy oil, but now there’s compelling evidence that canola oil is not the health food we’ve been led to believe it is.
The Origin of Canola Oil
Ever wonder where canola oil comes from?
After all, there is no such thing as a canola plant!
Canola stands for “Canadian oil low acid” and the oil comes from a form of rapeseed (Brassica napus) grown largely in Canada.
Rapeseed is a relative of mustard and is a member of the same group of plants as broccoli, cauliflower, and cabbage.
The name change from rapeseed to canola was a public relations move due to the bad connotation of the word rapeseed.
So, at least here in the US, it’s called canola oil, but in much of the world it’s still known as rapeseed oil or rape oil.
Canola Oil’s Unnatural Production Process
Canola oil is sometimes compared to olive oil since they are both high in monounsaturated fats.
But that is where the similarity ends.
Olives have been mechanically pressed for their oil for thousands of years.
Olive oil has a long history of use and is an essential part of the Mediterranean diet, which is considered the healthiest diet of all.
Until recently, the technology did not exist to make an edible oil from rapeseed, so its oil was used only to lubricate machinery.
In the 1950s, rapeseed oil was banned for human consumption due to its high levels of two toxic compounds, erucic acid and glucosinolate. (2)
Glucosinolates are bitter compounds that make the oil unpalatable and depress growth rates in animals. (5)
But in 1973, Canadian scientists bred these chemicals out of rapeseed so that it could be used for livestock feed.
Eventually, they figured out a way to make it a food fit for humans and, in 1978, the term “canola” was coined.
This new form of rapeseed was developed using traditional plant breeding methods, but now about 80% of rapeseed has been genetically modified to make it tolerant to the controversial herbicide Roundup. (6)
Getting rapeseed oil from seed to bottle is not easy and involves a lot of steps.
According to the Canola Council of Canada, once the seeds are sorted and cleaned they are heated repeatedly to 95-115°C (203 – 239°F) and washed with hexane.
The oil is then degummed with citric, malic, or phosphoric acid or sodium hydroxide — also known as lye or caustic soda.
Next, this degummed oil is washed with more sodium hydroxide, then filtered, bleached, and deodorized.
These steps are necessary to make a product that looks, smells, and tastes like anything consumers would consider eating.
The first two minutes of the short video below are pro-canola oil propaganda, but it gets interesting at the 2-minute mark where you’ll see the creation of unappetizing “canola cakes,” the precursor to canola oil.
Compare this to cold-pressed olive oil which is obtained by mechanical pressure only and you’ll see that canola oil doesn’t look all that “natural” anymore.
Pertinent fact: The top four vegetable oils in the US — soybean, canola, palm, and corn oil — are processed this way. They are referred to as RBD oils since they’ve been refined, bleached, and deodorized.
Why Canola Oil Is Thought to Be Healthy
Before we take a look at what’s wrong with canola oil, let’s take a look at why it is purported to be healthy.
According to the Harvard School of Public Health, canola oil is considered a healthy choice because it’s low in saturated fat, high in monounsaturated and polyunsaturated fats, and contains compounds called phytosterols that reduce the absorption of cholesterol into the body. (7)
However, consuming high levels of phytosterols can actually increase your risk of heart disease. (8)
And, once you dig a little deeper, most of canola’s supposed health benefits are not what they appear to be.
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8 Reasons Why Canola Oil Is Unhealthy
All that processing with heat and chemicals isn’t just unappetizing, it contributes considerably to making canola oil unhealthy.
Let’s take a look at the 8 main ways canola oil is bad for you, with an emphasis on how it affects your brain and mental health.
1. Canola Oil Is a Source of Unhealthy Trans Fats
Due to the high heat and chemicals used during processing, canola oil contains unhealthy trans fats even when the label states “0g trans fats” per serving. (9)
This is because the US Food and Drug Administration (FDA) allows processed food manufacturers to round down amounts so that anything less than 0.5 grams per serving can be listed as zero grams.
When you eat canola oil often, which is rather easy to do, this adds up.
One study found that store-bought canola oil contained up to 4.2% trans fats. (10)
The problem with trans fats is that they’ve been linked to heart disease, stroke, diabetes, obesity, cancer, and other diseases. (11)
Trans fats can increase your risk of depression by up to 50%. (14)
Trans fats are so detrimental that they’ve been totally banned in countries like Denmark, Austria, Hungary, Iceland, Norway, and Switzerland. (15)
In 2012, they were banned in New York City and the rest of the country is now following suit.
The FDA has declared trans fats unfit for human consumption and given food manufacturers until January 1st, 2021 to get them completely out of processed foods and fast food. (16)
2. Canola Oil Fuels Damaging Chronic Inflammation
Omega-3 essential fatty acids, like the kind found in fish oil, are widely recognized as extremely healthy.
A big reason for this is that they are anti-inflammatory.
Omega-6 essential fatty acids are pro-inflammatory and contribute to chronic inflammation — an underlying factor in seven of the top ten leading causes of death. (17)
The ideal diet would contain omega-3 essential fatty acids and omega-6 essential fatty acids in approximately a 1-to-1 ratio.
That is how our long-ago ancestors ate, but now the average American consumes 15 times more omega-6s than omega-3s due mainly to the widespread use of canola oil and other vegetable oils in the food supply. (18)
Note that some inflammation is a necessary health process — it’s your body’s first line of defense against infection and injury.
But this process can get stuck “on” and become chronic, especially when your body is overloaded with omega-6 fatty acids.
Chronic inflammation is detrimental to the body, attacking healthy cells, blood vessels, and tissues instead of protecting them.
Chronic inflammation can shut down energy production in brain cells and slow down the firing of neurons, contributing to ADHD, anxiety, brain fog, depression, memory loss, and even Alzheimer’s. (19)
Some experts believe that the omega-6 to omega-3 ratio is the most important health factor, while others believe it’s the actual intake of each that matters most.
The omega-6 to omega-3 ratio plays a role in depression, schizophrenia, mental performance, attention deficit hyperactivity disorder, and Alzheimer’s disease. (20)
But either way, there’s little doubt that we are eating more omega-6 fats than ever.
Dietary trends over the past few decades show striking increases in omega-6 fatty acid consumption from all sources, including canola oil. (21)
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3. Canola Oil Causes Harmful Oxidative Damage
Canola’s high polyunsaturated fat content is one of its selling points, yet these are the least stable kinds of fats for cooking.
The polyunsaturated fats found in canola oil are highly unstable when exposed to heat, light, solvents, or pressure. (22)
When a fat is unstable, it goes rancid and creates free radicals. (23)
Free radicals are unattached oxygen molecules that attack your cells in much the same way that oxygen attacks metal, causing it to rust.
You’ve witnessed free radical damage, also called oxidative damage, when you’ve seen a cut apple or avocado turn brown.
Free radicals cause cellular damage, premature aging, and even cell death.
Since brain cells are high oxygen users, they are particularly susceptible to free radical damage. (24)
Note: If you buy any vegetable oil, don’t buy it in a clear glass or plastic bottle as light exposure already will have caused some oxidation. (25)
4. Canola Oil Lacks Fats Essential for a Healthy Brain
Your brain is largely made of fat, 60% by weight, and the quality of your brain cells largely depends on the quality of the fats you eat. (26)
Of all the essential fatty acids, the omega-3s are the most abundant in the brain where they are the preferred building blocks of brain cell membranes and nerve cells. (27)
One omega-3 fatty acid in particular, DHA (docosahexaenoic acid), accounts for 97% of the omega-3 fatty acids in the brain. (28)
Besides being a major structural component, DHA also plays a role in brain cell communication.
DHA facilitates neurotransmitter activity and increases the number of neurotransmitter receptors, allowing the brain to optimize its use of feel-good brain chemicals like serotonin and dopamine. (29)
While there are some omega-3s in canola oil, they are alpha-linolenic acid (ALA), an inferior form.
Less than 0.5% of ALA gets converted to DHA, the form your brain prefers. (30)
5. Canola Oil Contains Hexane, a Known Neurotoxin
During canola oil’s manufacturing process, the rapeseed is washed in pure hexane.
Hexanes are a group of compounds that are a chief component in gasoline.
The US Environmental Protection Agency (EPA) classifies hexane as an air pollutant and the Centers for Disease Control and Prevention (CDC) considers it a neurotoxin. (31)
Besides being used as a solvent to extract oil from seeds, hexane is also used as a solvent for rubber cement, adhesives, varnishes, and inks.
Granted, the main way most of us are exposed to hexane is from inhaling gas fumes, and only trace amounts are found in canola oil. (32)
But with the long list of hexane’s side effects, do you really want to be eating any?
Acute exposure to hexane causes dizziness, giddiness, nausea, headache, dermatitis, and irritation of the eyes and throat. (33)
Chronic exposure can result in numbness in the extremities, muscular weakness, blurred vision, headache, and fatigue.
It’s possible to avoid hexane in canola oil by buying certified organic oil which by law cannot use solvents for extraction.
6. Canola Oil Increases the Risk of Mental Disorders
John Stein, a University of Oxford Emeritus Professor of Neuroscience, believes that the displacement of omega-3 fatty acids in the brain by omega-6s is having profound, unforeseen consequences on our brains and is contributing to the meteoric increase in mental health disorders. (34)
Some of the latest research supports this.
Replacing seed-based vegetable oils with olive oil can significantly decrease your risk of depression. (35)
An unhealthy omega-6 to omega-3 ratio also increases the risk of depression. (36)
There’s even a correlation between vegetable oil consumption and homicide rates. (37)
7. Canola Oil May Be Bad for Memory
While there haven’t been human studies on the effects of canola oil on memory, there have been animal studies.
One recent study found that supplementing the diet of mice with canola oil had some notable negative effects.
Researchers conducted two similar experiments.
They found that enriching the diet of mice with extra virgin olive oil reduced their brain levels of amyloid plaques and tau proteins, both of which are hallmarks of Alzheimer’s disease.
The mice also showed signs of memory improvement. (38)
In the second experiment, mice were fed a diet enriched with canola oil.
These mice showed an increase in both amyloid plaques and tau proteins.
The canola-fed mice also exhibited impairments in memory and ability to learn. (39)
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8. Using Canola Oil Is a Missed Opportunity for Eating Brain-Healthy Fats
One of the worst things about using canola oil is the missed opportunity cost of adding some very healthy fats to your diet instead.
Every time you pour canola-based dressing on your salad, you are not using extra virgin olive oil — one of the healthiest foods we have.
Every time you cook with canola oil, you are missing out on the chance to consume more brain-boosting coconut oil.
Coconut oil is one of the top brain foods due to its unique composition of medium chain triglycerides (MCTs) and lauric acid. (44)
Coconut oil’s MCTs act as a backup source of energy for your brain when blood glucose is low.
It’s this property that makes coconut oil a promising treatment for dementia, Alzheimer’s, and other neurological disorders.
Tips for Avoiding Canola Oil
It’s not easy to avoid canola oil.
It’s ubiquitous in restaurant food, fast food, and processed foods of all kinds.
The first tip for avoiding canola oil is to get in the habit of reading food labels.
It’s particularly discouraging that canola oil is the oil of choice in so many snacks and prepared foods marketed as “healthy” and found in every health food store.
So if you really want to limit your intake of canola oil, you’ll have to say goodbye to most processed foods and stick with “real” food that does not come pre-packaged in a box, bag, carton, bottle, or other container.
While eating mainly unprocessed foods can be hard because processed foods are so prevalent, in the long run it is one of the best dietary changes you can make.
Almost everything that’s bad about canola oil can also be said about other seed-based vegetable oils such as soy, sunflower, and safflower oil, so don’t make the mistake of switching to these instead.
Here are the oils and fats you should be eating for overall health and brain health:
Olive oil is a healthy monosaturated fat that is great to use as-is on salad and can be used in low-heat cooking as well.
You may have heard that you shouldn’t cook with olive oil, but this is a myth.
Heating — even for very long periods of time — does not degrade extra virgin olive oil’s nutrients. (47)
Extra virgin olive oil’s smoke point — the point at which degradation begins to occur — is around 374–405°F (190–207°C) which is higher than the temperature you would normally saute or stir fry food. (48, 49)
Coconut oil is a very brain-healthy fat that was previously vilified for containing saturated fat, but that’s what makes it so stable for cooking.
You can bake, saute, roast, and fry with coconut oil as you would other oils.
Additionally, you can add it to soups, smoothies, rice, or hot cereal.
And if you use any canola-based spreads, trade them in for real butter, especially butter from grass-fed cows.
Butter is now back as a healthy food! (50)
Butter’s health benefits are due mainly to its high butyrate content.
Butyrate is a fatty acid that is very therapeutic for the digestive tract and is powerfully anti-inflammatory. (51)
Why Canola Oil Is Bad for Brain Health: Take the Next Step
Canola oil is a popular vegetable oil that is highly processed and anything but natural.
It’s a main dietary source of inflammatory omega-6 fatty acids and damaging free radicals.
It negatively alters the structure and function of your brain.
It puts you at higher risk for mental disorders of all kinds.
Canola oil is found in virtually all processed, restaurant, and fast foods, so it can be hard to avoid.
You can start by reading labels and eating more food you’ve made at home with healthy fats like extra virgin olive oil and coconut oil.