Here is a summary of a few facts regarding Canola Oil:
# It is genetically engineered rapeseed.
# Canada paid the FDA the sum of $50 million to have rape seed registered and recognized as "safe". (Source: Young Again and others)
# Rapeseed is a lubricating oil used by small industry. It has never been meant for human consumption.
# It is derived from the mustard family and is considered a toxic and poisonous weed, which when processed, becomes rancid very quickly.
# It has been shown to cause lung cancer (Wall Street Journal: 6/7/95)
# It is very inexpensive to grow and harvest. Insects won't eat it.
# 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.
# Generally rapeseed has a cumulative effect, taking almost 10 years before symptoms begin to manifest. It has a tendency to inhibit proper metabolism of foods and prohibits normal enzyme function. Canola is a Trans Fatty Acid, which has shown to have a direct link to cancer. These Trans Fatty acids are labeled as hydrogenated or partially hydrogenated oils. Avoid all of them!
P.S - I guess only Olive oil and Extra virgin olive oil are the best options.
Source and more - http://www.karinya.com/canola.htm