Why canola oil isn’t as healthy as you think it is

canola-oilCanola oil is the highly processed end product derived from rapeseed, and may not be as healthy as you’ve been led to believe.

Though marketing campaigns designed to sell this (mostly) monounsaturated oil don’t make a big deal out of this fact, 90% of the rapeseed crop today has been genetically engineered by Monsanto, the biotech giant, to resist a commonly used herbicide, Roundup. (1)

So if you’re using canola oil that’s not labeled “Organic” or “Non-GMO,” you may be getting a whole different food product than you bargained for, along with an unwelcome effect on your health.

The jury’s still out on how foods categorized as Genetically Modified Organisms (GMOs) affect human health, but many of us would prefer a verdict before making our choices. This could take a while yet, since corporations focused on the bottom line exert great influence on the way these sort of dramas play out.

In the meantime, canola is presented as the ideal oil for everything from salad dressings, deep frying and stir-frying, as well as margarine for spreading on toast or melting over steamed broccoli or rice.

Some by-products from processing rapeseed into an edible oil are sold as animal food additives often used in hog and poultry production (2), which can add a new dimension to the idea that we are what we eat. Others are shipped off to factories where soap is manufactured.

It’s easy to see why this oil a cash crop for Canadian growers, isn’t it?

Genetically modified rapeseed is also grown in America and Australia to a lesser extent, but European countries ban the cultivation of GMO crops. (3)

Most people would never guess the oil was originally developed for industrial purposes, including biodiesel fuels and lubricants. (4)

The Makeover

Rapeseed oil is cheap to produce, but it tastes and smells bad.

It also contains erucic acid, a fatty acid that caused heart disease in lab rats. (5)

In order to make this oil palatable, Canadian scientists selectively bred rapeseed plants to minimize the bitter taste from glucosinolates (6) and drop the erucic acid content present in the original version until they had what they wanted: an edible, marketable oil with acceptable lipid profiles that could generate considerable profits even though it required considerable processing.

So canola is not a plant at all; it’s a made-up name that probably came from a combination of the words “Canada” and “oil.”

Commercial canola oil is processed with high heat, which oxidizes polyunsatured fatty acids so they become rancid. If a product contains less than 0.5 grams of trans fat per serving, labeling regulations allow the content to be listed as 9 grams. (7)

Since it’s becoming common knowledge that trans fats raise the risk of serious health disorders including heart disease (8, 9), and more people die of heart disease worldwide than from any other cause (10) , avoiding them seems wise.

A later processing step involves extracting oil from rapeseeds with hexane, a toxic solvent. Traces of this solvent can turn up in innocent-looking bottles of cooking oil. (11)

Let’s take a close look at what you’re getting when you bring home a bottle of canola oil to stock your pantry.

Dietary Fats: the Reign of Confusion

While it’s becoming more generally accepted that our bodies and brains need sources of healthy fat in order to function properly, it’s challenging to sort through all the conflicting information.

One of the health claims associated with canola oil is its low saturated fat content. Batches of oil can vary, but a typical average breakdown would look like this: (12)

  • 28% polyunsaturated fatty acids in an ideal ratio of omega-6 and omega-3 at 2:1
  • 63% monounsaturated fatty acids
  • 7% saturated fatty acids

Looks good, right?

In view of recent scientific evidence verifying that saturated fat actually has no effect on heart health, maybe it’s not such a big deal after all. (13, 14)

Olive oil is high in monounsaturated fats, and considered the gold standard for healthy oils. So let’s delve into the polyunsaturated content of canola oil.

Evolutionarily speaking, we never had access to large amounts of polyunsaturated fats until the advent of processed foods, so if we eat a good bit of canola oil, we’re treading unnatural territory.

The body incorporates these fatty acids, which tend toward oxidation, into cell membranes where free radicals resulting from the oxidizing process run rampant like bullies on a playground. Chain reactions can damage proteins and DNA molecules. (15)

And as mentioned above, during the multi-step process through which rapeseeds are refined, some of the fatty acids have turned rancid and changed into trans fats.


Since trans fats are associated with a higher risk for heart disease, that heart-healthy choice has just become a liability. (16, 17)

While you can read results from several clinical trials showing subjects eating canola oil dropped total cholesterol, LDL levels and triglycerides, it doesn’t fluff the numbers for HDL, the kind of cholesterol we want to go up. (18, 19) And these studies were short, often only a few weeks.

Long-term studies spanning years indicate vegetable oils can bump up the chances of developing heart disease. (20)


Some vegetables and seed oils can be healthy; for example, flax seed oil contains fatty acids the body can convert into omega-3 fatty acids, but the oil made from grapeseed is not your friend.

If you find organic canola oil that’s been cold pressed instead of heat-processed, it may not contain trans fats and won’t be genetically modified. But if you want good quality fat to to keep your brain cells firing and your muscles pumping, you’re better off using coconut or olive oil.

Read labels carefully; because its available as a super-cheap ingredient, canola oil is a commonly found on the ingredient list of many processed foods, like mayonnaise and bottled salad dressings.

Summary: Unless you’re comfortable with ultra-processed food products that are likely laced with trans fats, and have no concerns about the effects of GMO foods on your health, skip the canola oil.


  1. http://web.mit.edu/demoscience/Monsanto/about.html
  2. http://feedstuffsfoodlink.com/story-handling-inedible-food-production-byproducts-0-125735
  3. http://ens-newswire.com/2014/12/04/eu-countries-granted-the-right-to-ban-gmo-crops/
  4. http://www.gmo-compass.org/eng/grocery_shopping/crops/21.genetically_modified_rapeseed.html
  5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1277456/
  6. http://ajcn.nutrition.org/content/72/6/1424.short
  7. http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm053479.htm
  8. http://ajcn.nutrition.org/content/66/4/1006S.short
  9. http://jn.nutrition.org/content/135/3/562.short
  10. http://www.who.int/mediacentre/factsheets/fs310/en/
  11. http://www.westonaprice.org/health-topics/some-additives-in-vegetable-oils/
  12. http://nutritiondata.self.com/facts/fats-and-oils/621/2
  13. http://ajcn.nutrition.org/content/early/2010/01/13/ajcn.2009.27725.abstract
  14. http://archinte.jamanetwork.com/article.aspx?articleid=1108492
  15. http://www.ncbi.nlm.nih.gov/pubmed/5900208 http://www.ncbi.nlm.nih.gov/pubmed/12324287
  16. http://www.hsph.harvard.edu/nutritionsource/transfats/
  17. http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Trans-Fats_UCM_301120_Article.jsp
  18. http://www.tandfonline.com/doi/abs/10.1080/07315724.1991.10718149#.VhMcnPlVikp
  19. http://atvb.ahajournals.org/content/13/10/1533.short
  20. http://www.bmj.com/content/346/bmj.e8707 http://www.ncbi.nlm.nih.gov/pubmed/16387724
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