Q. I'm confused about cooking oils. I can't figure out which are safe for cooking, and which aren't. Can you clear this up for me?

A. Different oils perform best at different temperatures. Some, like sesame oil, can withstand high temperatures of up to 510 degrees, while others, such as flax oil, should never be heated.

One of the most important differences between oils pertains to their fatty acid structure. Flax oil, for instance, which is an omega-3 fat — essential for the health of your entire body — shouldn't be heated because heat will destroy its benefits and could make it harmful to your health. You can add flax oil to salad dressings or drizzle it on top of foods that have already been cooked. Olive oil, on the other hand — center stage in the heart-healthy Mediterranean diet — is a monounsaturated fat and safe to cook with, as long as it is not heated above 350 degrees.

You should avoid bringing any oil to its "smoke point" — the point at which it gets so hot that it smokes. When an oil reaches this point, it can break down and release free radicals and carcinogens (cancer-causing compounds) into the oil and air. If an oil that you are cooking with reaches this point, throw it out and start over with a clean pan and new oil, and cook at a lower temperature.

As a rule, you want to avoid eating fried foods. Foods that are lightly sauteed in the right oils, however, can be healthy. Always choose the best oil for the type of cooking that you're doing. Here are a few tips you can use to prepare foods with a wide variety of cooking oils: