Should Oils Ever Be Heated?

[Sir-Voor]

Are you saying heating oils reduces their health benefits, totally wipe-outs their health benefits, or makes them unhealthy?

I know getting oils above their flash point is not good for taste and I think reduces their health benefits, so it is good to know your oil’s flush point.

I find it hard to believe that heating oils below their flash point is so bad and never should be done.

[Sequoia]

Tara, could you please clarify your position on when, if ever, oils should be heated?

Specifically, what effect does heating have on nutritional value?

FWIW, I rarely cook with oil. When I use oils, I usually add them after the dish is cooked.

Thank you!

[nutritiontara]

When you heat an oil the molecular stucture is changed. It oxidizes. oxidized fats are called lipid peroxides. Lipid peroxidation creates a cascade of harmful free radicals which damages cell membranes. It also uses a great deal of antioxidants to neutralize these free radicals. Think of heated oils as margarin. Even those "whipped" tub spreads of supposedly good oil, have had air and heat introduced into them....causing lipid peroxidation.
If ya really wanta get precise: you should'nt cook any fat, even fats in meats, over ~? 225 degrees. I usually cook all my meat at 200 for longer. Even low heat, gently cooking things like eggs. Thats why you never buy "roasted" nuts, always raw...a quality high fat food but if you roast it, package it in plastic and stick it on a shelf for ?days, months? its rancid and full of free radicals.