Take one look at the modern production process for vegetable oil and this sort of effect is starting you right in the face. Palm, Canola, Rapeseed, Soybean, etc, they're all terrible. I avoid this shit like the plague.
Fortunately there's olive oil. Approximately 0.5 liters/month per person at $10/liter for organic extra virgin from Tunisia. Heard it too causes cancer if you fry it though...
Frying at low temperatures with olive oil is one of the "healthier" ways to fry, though. Less volatile aromatic hydrocarbons are produced when frying with olive oil compared to other fats, and some of the compounds in non-extra virgin olive oil reduce the production of free radicals.