RODALE NEWS, EMMAUS, PA—Internet rumors have circulated for years that heating olive oil will give you cancer and that canola oil is poisonous. And for the most part, those rumors have been proved false. But a new study published in the journal Occuptional and Environmental Medicine finds that cooking oils aren't totally benign. Norwegian researchers compared cooking oils and margarine and found that both release some toxic air pollutants when used to fry food at high temperatures. So the next time you're looking for the best cooking oil to protect your lungs and the taste of your food, consider what you'll be using it for.
THE DETAILS: The study was designed to simulate the conditions experienced by a chef in a restaurant kitchen. A 14-ounce beefsteak was fried either in margarine (made from nonhydrogenated palm, soybean, rapeseed, and coconut oils) or pure soybean oil (which, in the U.S., is often marketed simply as "vegetable oil" ) five times in a day for 15 minutes each, during which time the pan's temperature reached a high of 572 degrees F. The researchers repeated the experiment a total of four times, twice on an electric stove and twice on a gas stove. The researchers found that both oils on both stoves released high levels of naphthalene, a respiratory irritant found in gasoline and diesel fuels that's also used in moth repellents. Soybean oil used to fry the meat on a gas stove produced the highest levels of compounds called aldehydes, which are also components of gas and diesel that can irritate your eyes and respiratory tract. And while both oils emitted ultrafine particulates regardless of stove type, soybean oil emitted the most. Ultrafine particulates are the kind of particles you breathe in heavily polluted outdoor air, and they've been linked to lung disease, strokes, heart disease, and other problems like low birth weight in babies. The authors conclude that people should limit their exposure to cooking-oil fumes as much as possible, considering that no one knows how much of an exposure an individual can have before experiencing negative health affects.
Read on to see which cooking oils are best for your cooking needs.