My wife (not paleo, but generally agrees with whole foods approach) recently read an article in Eating Well magazine which said that Americans need to better balance 3:6 ratio by trading in sunflower and corn oil for canola oil (higher in 3), along with eating more fish, nuts and olive oil.
She knows my hate for canola is beyond words so she asked me for my opinion. I first looked up canola in the USDA database:
It is only about 30% polyunsaturated and the 6:3 ratio is ~2:1, which I believe is within the typical ratio that people target (I believe anywhere from 2:1 to 1:1). Interesting. Some arguments come to mind:
(1) The omega 3 in canola oil is plant-based (ALA) rather than (DHA/EPA). HOWEVER, so is the omega 3 in grass fed beef which none of us would have a problem with:
(2) Even if the ratio is reasonable, it is much better to use fats that are primarily saturated, because polyunsaturated fat is prone to oxidation and 30% is still high
(3) Doesn't necessarily apply to me, but most people on SAD are likely getting way to much n6, so ideally they should try to eat foods with a better than 2:1 ratio to offset the excess n6 rather than compounding the problem
I guess #2 should be enough of a good reason, but are there others? Many on here use the word "rancid" when referring to seed oils. What do we mean by that? Are they more likely to be oxidized before we cook with them then say nuts for example? Is that also by chance an argument that mainstream could pick up on? Why or why not?
UPDATE: Thanks everyone. Lots of great answers below, and the WAP article linked below is especially informative. Christopher makes a good point that this question could be asked about two different types of canola oil (1) industrially made and (2) non-GMO more naturally made canola oil. Though, I think #1 is much more pervasive so perhaps more relevant. The WAP article does seem to address #2 quite well also. Non-GMO rapeseed oil contains high levels of erucic acid which may be quite dangerous. Also, getting a bulk of your fat from monounsaturated fat is likely evolutionarily novel and some research shows it to be potentially dangerous.