I’m not aware of any scientific study that conclusively demonstrates either the health benefit or the toxicity of canola oil. However, with the exception of an organic cold-pressed canola oil product, I will avoid it because:
1. Most canola oil products are GMO. That probably has no effect on the safety of this product, but I have other issues with GMO foods.
2. The extraction process uses hexane, which is toxic. My concern is that traces of this remain in the oil.
3. Processing requires heat that alters the molecular structure so this results in unknowns. I am not willing to participate in a long term experiment to discover whether this is a problem. Also, the heating produces trans fat. This is definitely toxic and levels of trans fat have been found in canola oil products that far exceed what is reported by the manufacturers(1).
For more detail, see these articles:
Dr. Mercola: The Great Con-ola (Part 2)
Authority Nutrition: Canola Oil: Good or Bad?
The Environmental Working Group: HIDDEN IN PLAIN SIGHT – Trans Fat Hides in at Least a Quarter of Supermarket Foods
1. Journal of Food Lipids: LEVELS OF TRANS GEOMETRICAL ISOMERS OF ESSENTIAL FATTY ACIDS IN SOME UNHYDROGENATED U. S. VEGETABLE OILS