Rapeseed plants produce a substance called erucic acid that can be toxic in large amounts. Canola oil was developed in Canada by breeding rapeseed plants that produced much lower levels of erucic acid. Today's canola plants contain very little erucic acid, far below dangerous levels. Unfortunately, some people still misunderstand the difference between canola plants and the original rapeseed plants and there have been email hoaxes and rumors claiming that consuming canola oil is dangerous. But don't worry, these rumors are false. Actually, canola oil is probably good for you.
Canola oil contains monounsaturated fatty acids, similar to olive oil, and omega-3 polyunsaturated fatty acids called alpha linolenic acid, just like the fats found in flaxseed oil. Eating a diet rich in monounsaturated and omega-3 fatty acids may help reduce your risk for cardiovascular diseases and will help to reduce inflammation. Omega-3 fatty acids are also important for healthy nervous system function and for normal deoxyribonucleic acid (DNA) found in the cells of your body.
Canola oil also has less of the omega-6 fatty acids that are found in most vegetable oils such as sunflower, safflower, and corn oil. While we need some omega-6 fatty acids, the typical western diet has much more than we need. Many experts believe thet the combination of too little omega-3 fatty acids and too much omega-6 fatty acid intake contributes to pro-inflammatory conditions for the body, which can lead to increased risks of cardiovascular disease and other chronic health problems. This may be true, but we don't know exactly what the best ratio between omega-6 fatty acid intake and omega-3 fatty acid intake should be. Experts currently suggest that that ratio should probably be around 4:1 (Omega-6 to Omega-3). A typical western diet has a ratio of something around 16:1.
The United States Food and Drug Administration (FDA) allows food companies to make a qualified claim that canola oil is heart-healthy, so you'll often see it boldly presented on the product labels. And while it's true that omega-3 fats are good for your heart, you still need to watch your overall fat and calorie intake. Canola oil, just like all other fats, has nine calories per gram of oil, which is more than double the calories found in the same amount of protein or carbohydrate.
Sources:
de Lorgeril M, Salen P. "Alpha-linolenic acid and coronary heart disease." Nutr Metab Cardiovasc Dis. 2004 Jun;14(3):162-9.
Psota TL, Gebauer SK, Kris-Etherton P. "Dietary omega-3 fatty acid intake and cardiovascular risk." Am J Cardiol. 2006 Aug 21;98(4A):3i-18i.
Simopoulos AP. "Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic variation: nutritional implications for chronic diseases." Biomed Pharmacother. 2006 Nov;60(9):502-7.
United States Department of Agriculture, National Nutrient Database for Standard Reference. http://www.ars.usda.gov/Services/docs.htm?docid=8964. Accessed February 7, 2008.
