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HSI Jenny Thompson, Effects of Canola Oil

(2013-03-04 19:22:30) 下一個

Effects of Canola Oil


http://hsionline.com/2002/08/20/effects-of-canola-oil/


 

 


The new Big Oil


I received an e-mail last week from HSI Panelist Allan Spreen, M.D. who suggested I read a new article titled “The Great Con-ola” – an in-depth piece that could be subtitled “Everything You Always Wanted to Know About Canola Oil (but Were Afraid to Ask).”

What? You thought canola oil was the safe, “all natural” oil? Or had you read that it was pure poison? There are a lot of wild tales about canola oil out there. With Dr. Spreen’s help we’ll sort out the strange from the true.


 


Internet extremes


 
You can easily find a number of web sites filled with dire warnings about canola oil. Here’s a quote from one site called “The Dangers of Canola Oil”: “Some typical and possible side effects include loss of vision, disruption of the central nervous system, respiratory illness, anemia, constipation, increased incidence of heart disease and cancer, low birth weights in infants and irritability.”

If it was “typical” for even one percent of canola oil users to become blind, anemic, constipated, cancerous and (understandably) irritable, it’s hard to imagine that the cooking oil shelves at your local grocery store would still be lined with a dozen brands of canola oil. But there is at least a seed of truth in this “sky is falling” claim, and that will provide us with a good place to start: the rapeseed.


 


What’s in a name?


 
Rapeseed has been around for thousands of years, primarily cultivated in Asia and Europe. But rapeseed oil is loaded with erucic acid, which has been shown to cause lesions of the heart – not a good side effect. So a little genetic manipulation by some plant breeders in Canada created a variety of rapeseed that produced an oil low in erucic acid. They called it LEAR oil, an acronym for Low Erucic Acid Rapeseed.

Meanwhile, in the mid-1980s the food industry was looking for a new, inexpensive oil to increase production of processed foods. At the time, monosaturated oils, such as olive oil, were being touted as the healthy alternative to saturated and polyunsaturated oils. But olive oil couldn’t be produced in the quantities needed for mass production, so LEAR oil was settled on as the practical choice. But it needed a new, more commercial name. They settled on “canola” – for “Canadian oil.” And the marketing push was on.


Last week I told you about the importance of omega-3 fatty acids (“Loving the Monkey Life” 8/15/02) and their benefits to both the immune system and the cardiovascular system. Canola oil contains approximately 10 percent omega-3, giving it an obvious appeal to consumers who, by the mid-80s, were pursuing healthy diets as never before. A marketing strategy was developed to sell the nutritional benefits of canola alongside olive oil and the Mediterranean diet, already branded in the public consciousness as the gold standard of healthy diets.


And the strategy worked. By the mid-90s, canola was considered the healthy choice for cooking and processing. But was it really as healthy as nearly everyone in the food industry establishment claimed?


 


The zero factor


Canola oil is not a poisonous industrial oil, it doesn’t cause mad cow disease, and it doesn’t contain chemical warfare mustard gas. These are just three of the most extreme and completely unfounded claims about the horrors of canola.

But canola is not perfect. So far, no studies have been conducted to test the effect of canola oil on humans. But quite a few animal tests have been conducted, and the results are not promising. For instance, there are indications that canola is not healthy for the cardiovascular system, having caused lesions of the heart and vitamin E deficiency in rats. And ironically, one of the primary virtues that makes canola so appealing – the omega-3 fatty acid content – may in fact be the source of a primary problem.


Omega-3 fatty acids become rancid during the heat-intensive processing of canola oil, creating an unpleasant odor (in my mind, the smell is less of a concern than the rancidity, but I digress). The deodorization process turns a large amount of canola’s omega-3 into trans fatty acids. The Canadian government says the trans content of canola is 0.2 percent, but a University of Florida study found trans contents as high as 4.6 percent. This problem is even greater in processed foods where the hydrogenation process sends the trans fat content soaring to as much as 40 percent.


We’ve all heard the increasing debate over the dangers of trans fatty acids. This past July a panel of the National Academy of Sciences submitted a report on their attempt to set a safe intake level for trans fat. The panel reported that trans fat intake creates a serious risk of heart disease, just as saturated fat does. The report concluded with a recommendation that has no gray areas: the only safe intake of trans fatty acids is zero.


 


Doctor, doctorMr. MD


Sally Fallon and Mary G. Enig, Ph.D., the authors of the “con-ola” article, provide an exhaustive and comprehensive look at all the issues surrounding canola oil. But they stop short at making recommendations as to how much canola oil is too much, or if we should be avoiding it at all costs. When I put this question to Dr. Spreen, this was his response:

“Canola is EVERYWHERE, including in MOST HEALTH FOODS. I cannot find a single health nut granola cereal or bar that doesn’t have it (a few exceptions have soy oil). What’s worse, on the labels they call the products ALL NATURAL!!!”


“I don’t trust canola at all, for just the reason that there haven’t been anywhere near enough long-term observations. However, the chemical manipulations involved and the fact that it’s all being done due to being cheap stuff scares me. I’d say intake should be kept to a minimum (you can’t avoid it completelyit really is everywhere).”


So what’s the alternative? What oil should we be cooking with? Olive Oil?


“Extra virgin olive oil’s wonderful, but it does have a unique taste. I’m for real butter, palm kernel oil, coconut oil or even lard first, but the negative PR on saturated fat has pretty much killed the use of the last three. Fresh flax oil would be my next choice. (And did you know that the director of the Framingham study stated the exact opposite of what we’ve been told was the result of that study, specifically that the more saturated fat used, the better heart health people seemed to have?)”


For now, it would seem that the search will have to go on for a “magic” oil that we can use for processing and cooking with no adverse side effects. There have been polyunsaturated pretenders, there have been monosaturated contenders, but so far there is no king.


 

To Your Good Health,


Jenny Thompson
Health Sciences Institute

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