Once considered a specialty crop in Canada, canola has become a major North American cash crop. Canada and the United States produce between 7 and 10 million metric tons (tonnes) of canola seed per year. Annual Canadian exports total 3 to 4 million metric tons of the seed, 700,000 metric tons of canola oil and 1 million metric tons of canola meal. The United States is a net consumer of canola oil. The major customers of canola seed are Japan, Mexico, China and Pakistan, while the bulk of canola oil and meal goes to the United States, with smaller amounts shipped to Taiwan, Mexico, China, and Europe. World production of rapeseed oil in the 2002–2003 season was about 14 million metric tons.
Canola was developed through conventional plant breeding from rapeseed, an oilseed plant with roots in ancient civilization. The word "rape" in rapeseed comes from the Latin word "rapum," meaning turnip. Turnip, rutabaga, cabbage, Brussels sprouts, mustard and many other vegetables are related to the two canola species commonly grown: Brassica napus and Brassica rapa. The negative associations with the word "rape" resulted in the more marketing-friendly name "Canola". The change in name also serves to distinguish it from regular rapeseed oil, which has much higher erucic acid content.
Hundreds of years ago, Asians and Europeans used rapeseed oil in lamps. As time progressed, people employed it as a cooking oil and added it to foods. Its use was limited until the development of steam power, when machinists found rapeseed oil clung to water or steam-washed metal surfaces better than other lubricants. World War I saw high demand for the oil as a lubricant for the rapidly increasing number of steam engines in naval and merchant ships. When the war blocked European and Asian sources of rapeseed oil, a critical shortage developed and Canada began to expand its limited rapeseed production.
After the war, demand declined sharply and farmers began to look for other uses for the plant and its products. Edible rapeseed oil extracts were first put on the market in 1956–1957, but these suffered from several unacceptable characteristics. Rapeseed oil had a distinctive taste and a disagreeable greenish colour due to the presence of chlorophyll. It also contained a high concentration of erucic acid. Experiments on animals have pointed to the possibility that erucic acid, consumed in large quantities, may cause heart damage, though Indian researchers have published findings that call into question these conclusions and the implication that the consumption of mustard or rapeseed oil is dangerous. Feed meal from the rapeseed plant was not particularly appealing to livestock, due to high levels of sharp-tasting compounds called glucosinolates.
Plant breeders in Canada, where rapeseed had been grown (mainly in Saskatchewan) since 1936, worked to improve the quality of the plant. In 1968 Dr Baldur Stefansson of the University of Manitoba used selective breeding to develop a variety of rapeseed low in erucic acid. In 1974 another variety was produced low in both erucic acid and glucosinolates; it was named Canola, from Canadian oil, low acid.
A variety developed in 1998 is considered to be the most disease- and drought-resistant variety of Canola to date. This and other recent varieties have been produced by gene splicing techniques.
An Oregon State University researcher has determined that growing winter canola for hybrid seed appears possible in central Oregon, USA. Canola is the highest-producing oil-seed crop, but the state prohibits it from being grown in Deschutes, Jefferson and Crook counties because it may attract bees away from specialty seed crops such as carrots which require bees for pollination.
Canola was originally a trademark but is now a generic term for this variety of oil. In Canada, an official definition of canola is codified in Canadian law.
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Traditional rapeseed oil contains higher amounts of erucic acid and glucosinolates than the commercially-sold consumer variety, both of which were deemed undesirable for human consumption by the United States Food and Drug Administration (FDA). Erucic acid may be involved with cancer and rancidity and glucosinolates may be goitrogenic. Canola oil contains only 0.5 to 1% erucic acid, well below the 2 percent limit set by the USDA. In recent years, canola oil has been averaging 0.1% erucic acid.
For many years rapeseed oil was used for human consumption in Canada despite the possible undesirable effects of glucosinolates and erucic acid, which were considered to be acceptable due to the health benefits of the oil. Researchers were later able to develop "double-zero" varieties by the 1980s without significant levels of erucic acid or glucosinolates.
Nonetheless, controversy continued, with an article implicating Canola oil with glaucoma and Mad Cow Disease. This article was taken up, condensed and widely circulated in a story via email. The industry and many health professionals condemn this as an email hoax making wholly unsubstantiated claims.
In Spain, at the beginning of the 1980s, industrial rapeseed oil that had been sold as olive oil was blamed for the so-called toxic oil syndrome.
Other sources (such as The Weston Price Foundation ) have concerns about the possible health risks of Canola oil. Claims made by the Weston Price Foundation include: animal testing that indicates growth retardation, a higher incidence of heart lesions of the myocardium, decrease in platelet count and increase in platelet size, vitamin E deficiency, high blood pressure, and lowered life spans. In many of the studies cited by the Foundation, when saturated fats were added to the diets, health improved. The Weston Price Foundation also states that the modern process of extracting the oils with high-pressure mechanical pressing along with industrial solvent residue in the oil such as Hexane in itself can be toxic. These heat, high pressure and solvent processing methods are common with most contemporary vegetable oils. Since omega-3 fatty acids rapidly become offensive smelling and subject to rancidification when processed with high heat and oxygen, the oil is then subjected to a deodorizing process which removes much of the Omega-3 and replaces it with trans fats. The actual claims of the Omega 3 content of processed canola oil have been challenged by a study done at the University of Florida which found trans fat levels of up to 4.6 percent in commercial canola oil as opposed to the Canadian Governments assertion that the oil has 0.2 percent trans fat. Because of concerns about inhibited growth in human infants, canola oil is not permitted in infant formula by the FDA.
Contamination of conventional canola crops from neighbouring genetically engineered fields has been a serious problem for Canadian canola farmers. It is very difficult for farmers to grow non-GM crops because of the frequent contamination.
The most high-profile case of contamination is Monsanto Canada Inc. v. Schmeiser, where Monsanto sued Percy Schmeiser for patent infringement because his field was contaminated with Monsanto's patented Roundup Ready glyphosate tolerant canola. The supreme court ruled that Percy was in violation of Monsanto's patent because the crops were growing on his land, but he was not required to pay Monsanto damages since he did not benefit financially from its presence. On March 19, 2008, Schmeiser and Monsanto Canada Inc came to an out of court settlement whereby Monsanto will pay for the clean-up costs of the contamination which came to a total of $660 Canadian. Also part of the agreement was that there was no gag-order on the settlement and that Monsanto could be sued again if any further contamination occurred.
Introduction of the genetically modified crop to Australia is generating considerable controversy. Canola is Australia's third biggest crop, and is often used by wheat farmers as a break crop to improve soil quality. As of 2008 the only genetically modified crops in Australia were non-food crops: carnations and cotton. In 2003, Australia's gene technology regulator approved the release of canola altered to make it resistant to the herbicide Glufosinate ammonium.