Here is a quote:
"I love to cook with olive oil but use it for lower heat cooking.
Oils will begin to burn and thus smoke at a certain temperature. This is different for every oil. It is partly due to the composition of the oil but is also the result of impurities in the oil. An extra virgin olive oil that has a great fruit flavor will generally have more impurities that will lower the "smoke point" of the oil.
My favorite oil for higher heat cooking is grapeseed oil. The oil itself has a higher smoke point than olive oil and if you look for grapeseed oil that is not labeled "extra virgin" it will likely have fewer impurities.
It also a higher amount of mono-unsaturated fats than many oils with a low amount of trans-fatty acids and, consequently, it may actually help prevent heart disease. In research published in the Journal of Arteriosclerosis there was a remarkably beneficial effect of grapeseed oil on HDL (good) cholesterol. It appears that one ounce per day is enough, with the research showing a 13 to 14 percent increase in HDL cholesterol.
In another study published in Journal of the American College of Cardiology fifty-six participants with low HDL levels substituted up to 1.5 ounces of grapeseed oil for the oil they used in recipes. At the end of the study, the subjects showed no significant change in weight or total cholesterol, but the ratio of LDL to HDL had changed with a 7% reduction in LDL and a 13% increase in HDL levels.
1 tsp. grapeseed oil = 40 calories, 4.5g fat, 0.44g sat fat, 0.73g mono fat, 0g protein, 0g carbohydrates, 0mg sodium, 0mg cholesterol
Both olive oil and grapeseed oil are safe for people who use Coumadin® (warfarin)."
My best friend is a huge cook in NY, and also health freak- he says using high heat oils like Grape Seed are safe, and even better for high heat is Avocado Oil, but using low heat oils like Olive Oil is risky and unnecessary when it comes to molecular changes when brought to a boil. Using it for seasoning at the end is safe- again- provided your not bringing it to high heat.
(SAT FAT) (POLYUNSATFAT) ( MONOSATFAT) (SMOKE POINT)
Avocado 12% 74% 14% 271 °C
Grape seed oil 12% 17% 71% 204 °C
Olive oil (refined) 14% 73% 11% 225 °C
Olive oil (extra virgin) 14% 73% 11% 190 °C
Olive oil (extra light) 14% 73% 11% 242 °C
I hope this helps!