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The Great Olive Oil Misconception — Dr. Ornish Responds

In a Reader's Digest column, Dr. Dean Ornish reported that olive oil is not as healthy as everyone thinks it is. A number of readers were dismayed and disbelieving of this news, and others thought canola oil, which Dr. Ornish recommends, is unhealthy. Dr. Ornish addresses these concerns: First of all, on the health benefits of canola oil versus olive oil: Olive oil, like all oils, is 100% fat. Since fat has 9 calories per gram, whereas protein and carbohydrates have only 4 calories per gram, people consuming a lot of olive oil are also consuming a lot of extra calories. As I wrote in my column, olive oil “lowers” cholesterol only when substituted in equal amounts for foods that are higher in saturated fat. In other words, if you replace 60 grams of butter with 60 grams of olive oil, your LDL cholesterol level is likely to decrease—not because olive oil lowered your cholesterol level but because it didn’t raise it as much. This is a very common misconception, causing many people to consume a lot of olive oil in the belief that it will somehow magically lower their cholesterol levels. Studies comparing the effects of canola oil versus olive oil show that canola oil consumption results in lower LDL cholesterol levels. This is not surprising, since olive oil contains approximately 14% saturated fat, whereas canola oil has much less. It's clear that olive oil is a healthier fat than many others, but not as healthful as canola oil or fish oil. A study by Dr. Robert Vogel in the Journal of the American College of Cardiology found that olive oil significantly reduces blood flow to different parts of your body, whereas canola oil and salmon do not. This measure of blood flow, called flow-mediated vasodilation (FMD), is a standard, well-accepted test by the American Heart Association and others. In this study, blood flow (FMD) was reduced by 31% after an olive-oil meal but was not reduced by a meal with a similar amount of fat from canola oil or salmon, probably due to the higher content of the protective omega-3 fatty acids in canola oil and salmon. Okay, let’s address the second concern—that canola oil is “genetically engineered and literally poison." It’s neither. Canola oil comes from a hybrid plant developed in Canada during the late 1960s to 1970s using traditional pedigree hybrid propagation techniques (not genetically modified) involving black mustard, leaf mustard and turnip rapeseed. It has also been claimed that canola oil is used in making mustard gas, a poison. This is totally untrue. Actually, mustard gas doesn't even come from the mustard plant; it was so named because it smells similar to mustard. Canola oil has allegedly been used as an industrial lubricant and ingredient in fuels, soaps, paints, etc. The truth is that many vegetable oils, such as corn, soybean and flax are also used in these applications. That doesn't make those oils unhealthy or dangerous. Canola oil has also been accused of killing insects, such as aphids. Again, all other oils can do the same, not by poisoning insects, but by suffocating them. As described in a recent issue of the University of California, Berkeley, Wellness Letter, "Don’t believe the scary rumors about canola oil. The oil is not toxic, nor does it cause everything from heart disease to multiple sclerosis. It comes from a special type of rapeseed plant bred since the 1970s to be extremely low in certain toxic substances. The FDA and other agencies all agree that canola oil has no adverse effects. In fact, far from causing coronary artery disease, the oil is rich in heart healthy unsaturated fat—notably alpha-linolenic acid (an omega-3 fat, like that in fish oil). It is a good, inexpensive choice as a cooking or salad oil. Canola’s only drawback: like all oils, it has 125 calories per tablespoon." I believe that part of my value to Reader’s Digest is to provide readers with innovative perspectives that are science-based, even when they challenge conventional wisdom, ones that you may not be reading in other publications.  As I wrote in my column, I like the taste of olive oil and I use it sometimes. It’s a healthier fat than many others, but it’s not nearly as healthy as canola oil, fish oil and flaxseed oil.