Answer by Robert Rister:
The kind of “lesion” they are talking about is a hardening of the artery. Cholesterol gets stuck in the lining of the artery. This isn’t necesssarily a bad thing by itself. Every cell in the body needs cholesterol. The problem in arteries is that cholesterol also feeds a kind of white blood cell known as a macrophage. Macrophages are unusually large white blood cells. They can get “stuck” in the lining of an artery and live out their life span and die there. The job of macrophages is to “clean out” dead tissue and germs. More macrophages come along to remove the dead macrophage and also get stuck. They also die and still more macrophages pile on, eventually die, and calcify. The mass of white blood cells and cholesterol eventually “clogs” the artery. Arteries are ordinarily flexible, and they can widen themselves when they need to accommodate more blood flow. The “clog” stiffens the artery so that if a blood clot eventually comes along, it can stop blood flow completely at the site of the “lesion.” That’s what causes a heart attack. Canola doesn’t enter into this process directly, but it can contribute to the formation of inflammatory chemicals that tighten the arteries and increase the risk of a clot’s getting caught in the artery. It’s not that canola is absolutely “toxic.” If you get too much of it and similar fats there can be a problem. However, there have to be other things going on before this causes vascular disease.