A particular recommendation in these guidelines is to rely on vegetable oil as an important source of PUFA.
Making vegetable oil is a heavy-duty process that employs various petroleum solvents and other unattractive chemicals.
To get your daily requirement of PUFA from oil, you need the industrialized stuff.
Lumina/Stocksy United
This all may turn out to be just fine for our health.
But on the other hand, it may not.
Again, the jury is still out on the optimal distribution of PUFA in our diets.
(Should we be limiting omega6 PUFA?
Should we add lots ofomega3when we consume lots of omega6?)
In chefs terminology, they become rancid.
The problem with oxidation is not merely that vegetable oils may become unattractive to our sensibilities.
Almost everyone agrees that oxidized PUFA are a real hazard to our health.
Oh, and cooking with them can be a problem.
Cooking With Vegetable Oil
Oxidation is greatly accelerated with heating.
Different vegetable oils have different heat tolerances, but they all tend to oxidize to some degree.
(If your dinner is smoking on the stove, your cooking oil is being oxidized.)
But the longer you heat them, and the higher the temperature, the worse the problem.
They are cooked in vats of vegetable oil that sits at high heat for hours and hours and hours.
For all anyone knows, those fries are being soaked in a toxic, highly oxidized, atherosclerosis-and-cancer-producing goo.
However, this phenomenon has not been formally studied.
(Which company would want to study it, or would even allow it to be studied?)
So What Should You Do About Vegetable Oil?
For cooking at moderate heat, consider using olive oil.
But even with olive oil, you oughta keep it beneath the smoking point.
For cooking at higher temperatures, you might consider butter.
Yes, its a saturated fat.
But the thing about butter is that its very stable it does not oxidize readily.
It in addition to omega6 PUFA it contains MUFA and omega3 PUFA and has a relatively high smoke point.
Pharmacol Rep. 2013;65(2):288-304.
