It seemed few were asking the right questions at the time; namely 'What the hell is this stuff?'
Canola is a Canadian invention, created by cross-breeding the rapeseed plant, the oil of which is toxic for human and animal consumption, so that it no longer produces (much) of the toxic constituent erucic acid. International regulations differentiate canola oil from rapeseed by checking the erucic acid levels - if it has less than 2% erucic acid, and less than 30 µmoles glucosinolates, it's canola (a trademarked term, by the way).
But all that is rather academic. It doesn't really matter where the stuff comes from - the question is; is it healthy?
To be frank, no, it's not. One of the main reasons for this is rather ironic. One of the purported benefits of canola oil is that it contains omega-3 and omega-6 fats. If you haven't heard of these, you've probably been living under a rock for the last two decades. In the simplistic health advice proliferated by the mainstream media, these fats are "essential" and we can never get enough of them. Well great! If canola oil has a lot of omega-3s I'll just load up on that stuff and not have to bother eating stinky fish!
The problem is that these fats, particularly omega-3s, are extremely delicate and highly susceptible to oxidation, i.e. going rancid. Pressing seeds for oil exposes them to all the things that will make a delicate fat go rancid - heat (through friction, if nothing else), oxygen and light. And even if you're an evil seed-oil-producing company and don't care if your oil is rancid, causing massive biological damage to your customer base, your customers will. You see, rancid omega-3s smell and taste "fishy", something most customers find distasteful, to say the least. Nobody is going to use your oil for anything if it gives your cooking creation a certain "essence of fishmarket".
So what's a canola producer to do? Why you just subject the oil to over a dozen chemical stages to stabilize it, of course! From Your Medical Advice:
So in order to make that bottle last on a shelf, plus be able to withstand high heat cooking, you need over a dozen chemical stages to process canola into an oil that will not go rancid. These processes include not only hydrogenation but deodorization of the omega-3. This process can form as much as 40% trans fatty acids in canola, even more than soybean oil.That's right - trans fats. The health industry super-villain that completely messes up the biological systems of anyone who consumes them. The fats that kill an estimated 90,000 people per year in the US. The fats considered to be at least partially responsible for heart disease, type 2 diabetes, metabolic dysregulation, unchecked inflammation, endothelial dysfunction, cancer and probably a whole lot more.
And this doesn't even address the fact that almost all the canola on the market is genetically modified, with all the problems inherent to GMOs. Does canola still sound like a healthy oil? Again, from Your Medical Advice:
The following have been directly attributed to the canola con:The thing is, this information isn't new. Hell, that Your Medical Advice article is four years old. Dr. Mary Enig wrote Know Your Fats in 2000. In fact, the FDA banned the use of canola oil in infant formulas back in 1985 because it retarded growth! And no one thought that maybe there might be other things negatively associated with consuming canola? 'It's just babies that have a problem with it? OK. I should be fine then...'
- Canola depletes vitamin E which will impact chronic diseases like heart, cancer, Alzheimer's, and diabetes.
- Canola increases the rigidity of membranes (which is a major aging factor and trigger for degenerative diseases like diabetes).
- Canola has the potential to damage hearts creating fibrosis impairing the action of vitamin E (crucial in inflammation).
- In human studies there was an increase in lung cancers as well as heart damage.
- Canola has been found to shorten the lifespan of animals and in others it lowers the platelet count and increases the size of the platelet cells.
- Daily canola oil raised the triglycerides a staggering 47%.
The fact that canola oil is still out there on the shelves, in the ingredients list of all your favourite processed foods and in the deep fryers and cooking oil bottles of your favourite restaurants (it's true; ask) is a travesty. It'll be interesting to see, when the FDA ban on trans fats takes effect in 2018, whether we'll still see canola oil in all its current applications. I'm betting things won't change a bit.
High temperature during refining can create some trans acids, but the total amount of them in refined low-erucic rapeseed oil should be in the range 0.8-1%, much less than in margarine. Trans acids can be also created during frying and similar operations, due to high temperature. This is true for all oils (because they have unsaturated fatty acids).
Now, there is no "canola" in my country, but there is equivalent, a low-erucic acid rapeseed oil, and I would always prefer it over soybean or sunflower oils, because much higher ratio of omega-3 acids to omega-6 acids (despite all the loss) and neutral taste. By the way, this refined rapeseed oil in my country does have some of this fishy taste, if you actually pay attention. It's still better than all other plant oils (except maybe refined coconut oil) if you don't want to impart a specific taste to the food, it's just mostly neutral.
Of course the unrefined rapeseed oil is healthier, but not better for actual high-temperature cooking. And if you don't use high temperatures, why don't go for lineseed oil, which is even better healthwise? I even make mayonnaise out of lineseed (flax) oil sometimes (though rapeseed oil mayonnaise is tastier, for comparison soybean and sunflower mayonnaises taste crap to me). So for me it's mostly rapeseed for high temperature, and lineseed for low temperature. As for vitamin E, many of the oils have it in varying amount, but one spoon of fish oil a day is enough to not to worry about it.