Canola oil is rapeseed oil that has been refined to be odorless. Unrefined rapeseed oil is a common cooking oil here in China. Now, I'm perfectly content to use delicious, delicious lard all the time. But every now and then I might want to make some Sichuanese food, which tends to use copious amounts of oil. Rapeseed oil would be the traditional choice. Have any of you heard about how unprocessed rapeseed oil compares to canola oil or other veg oils? I just read one source that claims it makes people ill. Is this true? If it were I'd expect the elderly Chinese people who live around me to be dropping dead left and right.
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It's been said before, but since the question came up again I figured the definitive (in my mind at least) article on canola oil was worth mentioning...
CANOLA OIL STUDIES (excerpt from The Great Con-ola by Sally Fallon) Full article can be found at http://www.whale.to/a/fallon.html (great read btw, highly recommended!)
Says Professor Wolke: "I found no research studies indicating that today's low-erucic-acid canola oil, as distinguished from ordinary rapeseed oil, is harmful to humans." That's because, even though canola oil now has GRAS status, no long-term studies on humans have been done.
Animal studies on Low Erucic Acid Rapeseed oil were performed when the oil was first developed and have continued to the present. The results challenge not only the health claims made for canola oil, but also the theoretical underpinnings of the diet-heart hypothesis.
The first published studies on the new oil were performed in 1978 at the Unilever research facility in the Netherlands.11 The industry was naturally interested to know whether the new LEAR oil caused heart lesions in test animals. In earlier studies, animals fed high-erucic-acid rapeseed oil showed growth retardation and undesirable changes in various organs, especially the heart - a discovery that touched off the so-called "erucic acid crisis" and spurred plant geneticists to develop new versions of the seed.
The results of the LEAR study were mixed. Rats genetically selected to be prone to heart lesions developed more lesions on the LEAR oil and the flax oil than those on olive oil or sunflower oil, leading researchers to speculate that the omega-3 fatty acids (not erucic acid) in LEAR and flax oil might be the culprit. But rats genetically selected to be resistant to heart lesions showed no significant difference between the four oils tested, and LEAR oil did not cause heart problems in mice, in contrast to high-erucic oil which induced severe cardiac necrosis.
In 1979, researchers at the Canadian Institute for Food Science and Technology pooled the results of 23 experiments involving rats at four independent laboratories. All looked at the effects of LEAR and other oils on the incidence of heart lesions. They found that saturated fats (palmitic and stearic acids) were protective against heart lesions, but that high levels of omega-3 fatty acids correlated with high levels of lesions. They found a lesser correlation with heart lesions and erucic acid.12
In 1982, the same research group published a paper that looked at the interaction of saturated fats with LEAR oil and soybean oil. When saturated fats in the form of cocoa butter were added to the diets, the rats in both groups had better growth and a significant lowering of heart lesions.
Said the authors: "These results support the hypothesis that myocardial lesions in male rats are related to the balance of dietary fatty acids and not to cardiotoxic contaminants in the oils."13
Canadian researchers looked at LEAR oils again in 1997. They found that piglets fed milk replacement containing canola oil showed signs of vitamin E deficiency, even though the milk replacement contained adequate amounts of vitamin E.14 Piglets fed soybean oil-based milk replacement, fortified with the same amount of vitamin E, did not show an increased requirement for vitamin E.
Vitamin E protects cell membranes against free radical damage and is vital to a healthy cardiovascular system. In a 1998 paper, the same research group reported that piglets fed canola oil suffered from a decrease in platelet count and an increase in platelet size.15 Bleeding time was longer in piglets fed both canola oil and rapeseed oil. These changes were mitigated by the addition of saturated fatty acids from either cocoa butter or coconut oil to the piglets' diet. These results were confirmed in another study a year later. Canola oil was found to suppress the normal developmental increase in platelet count.16
Finally, studies carried out at the Health Research and Toxicology Research Divisions in Ottawa, Canada, discovered that rats bred to have high blood pressure and proneness to stroke had shortened life-spans when fed canola oil as the sole source of fat.17 The results of a later study suggested that the culprit was the sterol compounds in the oil, which "make the cell membrane more rigid" and contribute to the shortened life-span of the animals.18
These studies all point in the same direction: that canola oil is definitely not healthy for the cardiovascular system. Like rapeseed oil, its predecessor, canola oil is associated with fibrotic lesions of the heart. It also causes vitamin E deficiency, undesirable changes in the blood platelets, and shortened life-span in stroke-prone rats when it was the only oil in the animals' diet. Furthermore, it seems to retard growth, which is why the FDA does not allow the use of canola oil in infant formula.19
When saturated fats are added to the diet, the undesirable effects of canola oil are mitigated. Most interesting of all is the fact that many studies show that the problems with canola oil are not related to the content of erucic acid, but more with the high levels of omega-3 fatty acids and low levels of saturated fats.
The main problem is it is from a seed and has unstable PUFAs. It's not a natural food for humans and most of it these days is probably GMO. If I were cooking low heat and wanted an oil, olive oil would work. For high heat, like in most asian dishes, I'd use coconut oil.
With so many great cooking oils out there (coconut, avocado, animal fats) why would you bother with something called rapeseed oil? (I know, I know, it's a member of a group of plants called rapes, but still..)
Whether "refined" or not... it's still going to be refined when you take a teeny, tiny seed and try to extract oil from it.
Think about an olive and how machinery can cold-press oil from it.
Now think about a rapeseed (if you even know what one looks like, I don't) or a sesame seed... and imagine what it takes to get oil from it. Many seed oils use chemical solvent extraction methods to get the oils out of the seeds. I wouldn't personally eat them in my own home. That's typically my test for whether or not I'd recommend them to clients.
Here's my full take on fats & oils: http://www.balancedbites.com/2010/07/fats-which-to-eat-and-which-to-ditch.html
High heat with unrefined canola oil is problematic, because it is so low in saturated fat, and has been shown to be associated with lung cancer. At lower heat levels, there aren't many studies to show it is horrible, it just isn't optimal. [side note: refined rapeseed oil has been used in the diesel trucking industry, and heavy equipment industry as a lubricant. USA relied heavily upon it during WWII]
Now true, many Asian cultures have been using rapeseed oil in refined and unrefined states for centuries. I suspect that those plants (of which radishes, turnips and cabbages are in the same family) may not be GMO crops, where as they probably are if grown in the USA.
So you want to know if you should or should not consume. Are you of 100% Asian ancestry? If so, you might be 'immune' to its effects. If you're concerned, find an oil that can take high heat, that is unrefined and virtually tasteless and your Sichuan feasts can continue, with no-one being the wiser.
And, if you are eating in an Asian restaurant, they probably are cooking with rapeseed oil. But I'm fairly certain their source of that oil is x-USA.
I have got to wonder how you all deal with arugula (eruca sativa) which is of course full of erucic acid (the acid was first discovered in arugula, hence the name). I try to avoid canola and eat modest amounts of arugula compared to other greens...
Im a chef with a specialty in organic foods and a strong interest in health food, and I LOVE rapeseed oil, is by far one of the best oils if you want low amouts of saturated fat and a very high level of omega 3. Its called the Nordic Oliveoil, and almost NEVER contains GMO since GMO is not widely used in Scandinavia. I use rapeseed oil alot, and its just wonderful and its only the cheap refined oils that smell when you warm it up.. The prosses of extracting oil from the flowers, is very easy since 40-50% of the weight of the flower is pure oil. The flowers are simply squeezed... I recomend it ANY day as a great alternative to olive oil. PRAISE TO RAPESEED Oil :) alittle info... http://www.wharfevalleyfarms.co.uk/why-rapeseed-oil/default.aspx
The rapeseed oil I use is cold-pressed: http://www.yorkshiresoriginal.co.uk/