Myth: Heating Olive Oil Will Make it Saturated or Trans-fatty.
One common myth is that heating olive oil will make it saturated or trans-fatty.
This is not true. As far as making a saturated fat, according to Dr. A. Kiritsakis, a world renowned oil chemist in Athens, in his book Olive Oil from the Tree to the Table -Second edition 1998, all oils will oxidize and hydrogenate to a tiny degree if repeatedly heated to very high temperatures such as is done in commercial frying operations. Olive-pomace oils and virgin olive oils are both highly monounsaturated oils and therefore resistant to oxidation and hydrogenation. Studies have shown oxidation and hydrogenation occurs to a lesser degree in olive oil than in other oils. But in any case, the amount of hydrogenation is miniscule and no home cook would ever experience this problem.
The large refinery-like factories that take unsaturated vegetable oil and turn it into margarine or vegetable lard do so by bubbling hydrogen gas through 250 to 400ºF (121 to 204ºC) hot vegetable oil in the presence of a metal catalyst, usually nickel or platinum. The process can take several hours. You cannot make a saturated product like margarine at home by heating olive oil or any other vegetable oil in a pan. We don’t know where this weird notion has come from. For more details, see Olive Chemistry.
Changing a cis-fat to a trans-fat does not occur on a home stove.
Myth: Cooking with Olive oil Diminishes The Nutritional Value of the Food.
Another myth is that cooking in olive oil diminishes the nutritional value of the food. This a misconception. The fact is that heating food will break down its nutritional value. High heat such as frying is worse than moderate heat such as steaming, which is worse than eating vegetables raw. It is not the cooking oil per se, but the high heat of frying. We are not aware of any edible cooking oil which by itself diminishes the nutritional value of the food cooked in it. Most nutritionists recommend lightly steaming vegetables or eating them raw. A touch of a flavorsome extra virgin olive oil added at the table will add taste and healthful anti-oxidants. Such is the Mediterranean diet which has been shown to help prevent coronary disease and have other health benefits.