Hoo..So use canola oil for cooking for better health.
Best Heart Benefits From Canola and Fish Oils -- Not Olive Oil By Jeanie Lerche Davis
http://my.webmd.com/content/article/13/1728_55672?src=Inktomi&condition=Home%20&%20Top%20Stories
WebMD Medical NewsMarch 14, 2000 (Atlanta) -- Olive oil may be nearly as dangerous as saturated fat in clogging arteries, according to authors of a study comparing the effects of canola, olive, and fish oils. They presented their findings today at the American College of Cardiology meeting in Anaheim, Calif.
"We expected there to be no detrimental effects at all because they were all good oils. What we found is that two were good and one was not -- olive oil. Olive oil impaired vascular function just like a Big Mac or fries or Sara Lee cheesecake," says Robert Vogel, MD, head of cardiology at the University of Maryland in Baltimore. He tells WebMD that the study's results "represent a major change in terms of what we should be telling people about what they should eat."
Vogel has long been recognized for his work regarding diet and health. "There is such confusion in the population as far as what's good and what's bad," he says. His research specifically focuses on the endothelium, which is the lining of blood vessels such as arteries and veins. When the endothelium is injured, it triggers atherosclerosis, which is the buildup of fatty substances on the blood vessel's walls that leads to heart disease.
His study is based on the famous Lyon Diet Heart Study, published in 1999, which showed that the low incidence of heart disease of coastal Mediterranean residents was due to a "Mediterranean diet" of bread, vegetables and fish, less meat (red meat replaced by poultry), fruit, and -- not olive oil -- but canola oil.
"Most people don't realize that the Lyon diet did not use olive oil. Volunteers in the study didn't particularly like the taste of olive oil, so they substituted with canola oil," says Vogel. "It's fascinating. ... Although they may have made part of their decision based on the tastes of the volunteers, it was actually a very smart thing to do."
In his study, Vogel and colleagues compared olive oil -- which is very much a part of a traditional Mediterranean diet -- with canola and fish oil. Ten volunteers, all with normal cholesterol levels, were given three meals composed of canola oil and bread, olive oil and bread, or salmon, with each meal totaling 50 g of fat.
Both before and after the meals, arterial blood flow in each volunteer's arm was measured using a technique that combines ultrasound and a blood pressure cuff. "We can watch what happens to the size of the artery when we increase blood flow. Normally, the artery should increase 10-15% in diameter. If it doesn't increase, you don't have normal [blood flow]," he tells WebMD. Arterial blood flow can be an indicator of whether the lining of the arteries -- the endothelium -- has been damaged, Vogel says.
The olive oil meal caused vessels to constrict by 34%, whereas the canola oil and salmon meals caused insignificant changes in blood vessels, Vogel reports. Because such constrictions injure the blood vessels' endothelium, they contribute to heart disease.
"We showed that omega-3 fats [the kind of fat found in fish] cause no impairment in [blood vessel] function, but olive oil with omega-9 fats does. The real importance is not whether it's monounsaturated or polyunsaturated; it's whether it's omega-3," Vogel says. Canola oil is enriched with omega-3.
Laurence Sperling, MD, medical director of preventive cardiology at Emory University School of Medicine in Atlanta, reviewed the study for WebMD. "I think this is an interesting finding and it explores a bit more the impressive benefit that was seen in the Lyon Heart Trial," he tells WebMD. "There was a lot of speculation about the benefit -- was it due to various components of the diet ... or the fact that [Mediterranean people] eat a lot more foods prepared with olive oil?"
Noting the study's very small size, Sperling says that it is a "well-done study. There's a lot of good data to suggest that this is a good measure of the [health] of the blood vessel."
Ronald M. Krauss, MD, head of molecular medicine at the Department of Energy's Lawrence Berkeley National Laboratory in Berkeley, Calif., tells WebMD that Vogel has been a leader in studying the ability of the blood vessels to dilate and allow more blood to flow. "His method of doing the measurement is pretty well established," Krauss says, however "this [study's] observation should be confirmed in larger studies and not interpreted to point the finger away from olive oil until we have a real clear picture whether this is consistent and until we understand the mechanism."
Vital Information:
In a small study comparing different types of oil, olive oil was found to be potentially damaging to blood vessels, while canola oil and fish oil were not harmful.
Canola oil and fish oil contain omega-3 fats, but olive oil contains omega-9 fats.
One expert cautions that more studies on a larger number of people are needed before these results can be confirmed.
