Updated September 21, 2007

Cooking Oils

by Lea Ann Holzmeister, R.D., C.D.E.

Flaxseed oil. This oil is made from the seeds of the flax plant and is often used as a dietary supplement rather than a cooking oil. It is high in omega-3 fatty acids and contains a group of chemicals called lignans that may play a role in cancer prevention.

Grapeseed oil. This light-tasting, medium-yellow oil is pressed from seeds of various varieties of grapes and is a by-product of wine making. It has a high smoke point and is typically used in salad dressings and marinades and for stir-frying.

Safflower oil. This oil made from the seeds of the safflower plant is almost flavorless and colorless. It is a favorite for salad dressing, because it does not solidify when chilled, and is also used in cooking. Safflower oil that is labeled “high-oleic” has a higher monounsaturated fat content than safflower oil that is not so labeled.

Soybean oil. This refined, mild oil is produced by cracking soybeans and chemically extracting the oil. Soybean oil is high in omega-3 fatty acids and is used extensively in commercially prepared foods but less often as a home cooking oil.

Sunflower oil. This light, odorless oil is pressed from sunflower seeds and is a good all-purpose oil. Like safflower oil, sunflower oil labeled “high-oleic” is higher in monounsaturated fat than sunflower oil not labeled with that term.

Walnut oil. This oil is extracted from walnuts and has a delicate, nutty flavor. It is high in omega-3 fatty acids but is not used for high-temperature cooking because heating it can diminish the flavor and produce a slight bitterness.

Oils high in saturated fats
A high intake of oils high in saturated fat can lead to a high LDL cholesterol level.

Coconut oil. This oil, also known as coconut butter, is extracted from the inner flesh of coconuts. It has a longer shelf life than other vegetable oils and is highest in saturated fat of all cooking oils. Unrefined, or virgin, coconut oil is derived from fresh coconut. Refined coconut oil is derived from copra, the dried coconut meat.

Palm oil. Palm oil is obtained from the fruit of the palm tree. It is reddish in color because it contains high amounts of beta-carotene. It is also high in saturated fat and semisolid at room temperature. Palm oil is the most widely produced vegetable oil in the world and is used primarily in processed foods.

Palm kernel oil. Palm kernel oil is extracted from the seeds, or kernels, of the palm fruit. It is also high in saturated fat and is most widely used in processed foods.

Storing oils
All cooking oils, whether refined or unrefined, are sensitive to light, heat, and exposure to oxygen (air). Cooking oil that is spoiled (rancid) will have an unpleasant smell and taste. To prevent spoilage, store oils in the refrigerator or in a cool, dark place. Oils may thicken in the refrigerator, but they will return to liquid if left standing at room temperature. Refined oils that are high in monounsaturated fats will keep for up to a year. Cooking oils high in polyunsaturated fats such as soybean, corn, safflower, and canola spoil more quickly: If stored properly, these oils will keep for up to six months. Some manufacturers put “use by” dates on product labels.

Choosing a cooking oil
Remember that all cooking oils contain the same number of calories—about 120 calories per tablespoon—and contain no trans fat or cholesterol. Because cooking oils are 100% fat and are high in calories, use as little as possible. To minimize the amount of oil you use when cooking on the stovetop, try using nonstick pans and an oil mister to spray a thin coating of oil onto the pan. When you need more than a thin coating of oil, use measuring spoons or cups to carefully measure out the desired amount.

Lea Ann Holzmeister is a Diabetes Nutrition Specialist and the author of The Ultimate Calorie, Carb, & Fat Gram Counter.

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