In general, monounsaturated fat increases the stability of a vegetable oil in comparison to polyunsaturated fat. Even though the high-MUFA composition of extra virgin olive oil increases its chemical stability, it does not protect this wonderful oil from most stovetop or oven cooking temperatures.
It is worth noting in this discussion of MUFAs that the oleic acid found in olive oil has been the subject of expanding research interest when it comes to insulin resistance, cancer, and cardiovascular disease. Recent studies have made it clear that oleic acid can directly alter the activity of certain cancer genes and appears to have anti-cancer effects that may be part of the Mediterranean diet's health benefits.
This primary MUFA in extra virgin olive oil may also help to lower a person's risk of insulin resistance as well as favorably altering some of the blood fat patterns that can be associated with risk of cardiovascular disease. Yet, to get these benefits it's important to enjoy extra virgin olive oil when its MUFAs are best protected, which means at heats below 250˚F (121˚C).
Read the entire article.