Both canola oil and sunflower oil are used for cooking and salad dressings, and both provide nutrients. Oils contain essential fatty acids needed for growth and development, and promote absorption of vitamins A, D, E and K. The question of whether to use canola or sunflower oil is complicated by the fact that three varieties of sunflower oil are commercially available, all with varying amounts of polyunsaturated and monounsaturated fats. Nutritionists generally consider canola oil to be more beneficial than sunflower oil, but both are are relatively healthy choices. Your decision may come down to personal taste.
The Basics
Canola oil is derived from the canola plant, which has been adapted from the rapeseed plant by Canadian growers; it takes its name from the words "Canadian" and "oil." Although rapeseed plants contain erucic acid -- toxic to humans in large amounts -- canola plants have been genetically engineered to yield a monounsaturated oil that is low in erucic acid; the Food and Drug Administration recognizes canola oil as generally safe. Sunflower oil is made from the striped black-and-white seeds of the sunflower plant, botanically known as Helianthius annuis. It has a lower smoke point -- or point at which it begins to break down -- than canola oil; the latter is a better choice for stir frying. Both canola oil and sunflower oils have almost identical amounts of calories -- weighing in at roughly 120 per tablespoon -- as well as about 14 g of total fat.
Fats in Sunflower Oil
Linoleic sunflower oil is high in polyunsaturated fats, and contains linoleic acid, which is converted by the body into beneficial gamma-linolenic acid, or GLA. According to Good Fats, GLA may help alleviate symptoms of diabetes and arthritis. LSO has a light, subtle taste and a high smoke point, making it an effective cooking oil. However, a tablespoon of LSO contains 11 percent saturated fat -- the least healthy type, next to trans fats. A second variety of sunflower oil, high oleic sunflower oil, contains 80 percent healthy monounsaturated fats -- the same type of fats found in nuts -- and only 9 percent saturated fat; this fatty acid profile makes it the healthiest of the sunflower oils. Nu-Sun is a mid-oleic sunflower oil, and blends attributes of the other two sunflower oils. It contains 55 to 75 percent monounsaturated fats, 26 percent polyunsaturated fats and 9 percent saturated fats.
Fats in Canola Oil
Canola oil is lower in unhealthy saturated fats than any of the three types of sunflower oil. It is also rich in omega-3 fatty acids. In addition, it contains close to 9 g of monounsaturated fats per tablespoon-- almost as much as high-oleic sunflower oil, which provides roughly 11 g per tablespoon. Monounsaturated fats lower destructive LDL cholesterol without affecting levels of healthy HDL. In contrast, polyunsaturated fats lower both types indiscriminately. Citing canola oil's low saturated fat level and healthy omega-3 content, Askdrsears.com lists canola oil as healthier than sunflower oils.
Vitamin E
Both canola oil and sunflower oils are practically devoid of vitamins and minerals except for vitamin E, in the form of alpha-tocopherols. When it comes to providing this fat-soluble vitamin, sunflower oils beat canola oil hands-down. All three sunflower oils contain more than 5 mg of alpha-tocopherols per tablespoon -- or a third of the recommended daily value -- while canola oil offers less than 2 1/2 mg. Vitamin E, a potent antioxidant, is important for immune system function.
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