do you think heating the olive oil might cause to loose the nutition values?

Not sure but they do say it's better to cook with. On tv earlier they said to soak your hands and nails in olive oil to soften your hands.

Olive oil comes in two different grades, One for marinating like salads and meats or poultry, and the heavier grade for cooking, read the label, you'll see. Its always better to use a low heat too!

Most oils will not break down in heat. I would venture to guess that cooking with any oils barely, if at all, changes anything but the viscosity of the oil.

I try not to use high heat with olive oil. It's better to use it for salads or as a flavoring AFTER cooking the food. Safflower, sunflower, and soybean oils have higher smoke points so they can be heated up to 450 degrees before the flavor and nutritional value are altered. Once oil reaches its smoke point, harmful carcinogens are created.