Canola is an oilseed crop grown on farms around the world, used in the production of animal feed, vegetable oils, and more recently biodiesel. It has a lower saturated fats and has more beneficial fatty acids for humans than many other oilseed crops.
Source and name
The name "canola" was given to rapeseed crops and products relatively recently. Some think that the reason for this renaming is the elimination of the obvious connotation of the name "rapeseed." However, the actual reason is more political and practical. The FDA banned rapeseed oil for human consumption in 1956 due to the high quantities of the toxic erucic acid. It also contained Glucosinolates, which gave the oil a bitter taste. Then in the 1970s, a different variety of rapeseed was bred by Canadians, which had a lesser concentration of this toxin. They wanted it known as "Canadian oil, low acid" to show that this is a safer alternative. Form this phrase, they derived the name "Canola," which they registered as a trademark. This name became very popular, however, and they eventually released the trademark. Even though much of this low-erucic rapeseed oil is now produced in countries other than Canada, this name is still generally used.
Canola oil has been advertized for some time as the "healthiest oil." This is stated because saturated fats are commonly believed to be unhealthy (though some disagree) and Canola oil contains only 7% saturated fat.
Omega-3 fatty acid is generally recognized as healthy. To be more specific, most professionals say that Omega-3 should be consumed half as much as Omega-6 (a 2:1 ratio). While this may sound counter intuitive, Omega-3 is much more rare than Omega-6. As a result, many people end up getting something more like a 40:1 ratio--that means forty times as much Omega-6 is consumed as Omega-3. Getting back to Canola oil, it is true that it does contain some Omega-3. However, it contains much more Omega-6. Canola oil consists of 20% omega-6, and only 9% omega-3 fatty acid. This 20:9 ratio provides just over the recommended amount of Omega-6. By itself, this seems like a nearly ideal oil. However, if one considers the entire diet, many other oils are being consumed. Safflower, Sunflower, Corn, Cottonseed, Sesame, and Peanut oils contain only Omega-6 fatty acid, and a number of other popular oils are predominantly Omega-6, with only a token amount of Omega-3. Since many of these other oils are consumed in quantity by the public, a higher intake of Omega-3 is needed than Canola oil can offer.
Artificial genetic modification
Over 90% of the Canola crops grown today have been genetically modified to resist the powerful herbicide Glyphosate (the active ingredient in Round-up and other weed killers). There is a myriad of reasons why genetically modified organisms (GMOs) are a concern for many people. For this reason, canola oil is often frowned upon my such health-conscious people.
Some still question whether this newer breed of rapeseed is edible. It still contains some erucic acid which could not be replaced. Some also point to the fact that the Canadian government paid the FDA $50 million to get their rapeseed (by then, renamed as Canola) approved. It is true that the FDA often charges an approval fee, but this seems excessive to many people.