Experts recommend frying foods in coconut or extra virgin olive oil as opposed to vegetable oils.
They even go so far as to say that using lard or butter poses fewer health risks than frying foods in safflower or corn oils.
This is because heating vegetable oils, especially at intense temperatures, releases toxic compounds known as aldehydes, which have been linked to illnesses including cancer, heart disease and dementia. via Telegraph
Cooking And Aldehydes
Aldehydes are created and emitted during deep frying at extreme temperatures.
A study conducted by the Environmental Engineering Department of the University of Dayton demonstrated that aldehydes are released when canola, olive, and extra virgin olive oil are heated at temperatures higher than 350°F.
In fact, Martin Grootveld, a professor of bioanalytical chemistry and chemical pathology, said that his research showed “a typical meal of fish and chips”, fried in vegetable oil, contained as much as 100 to 200 times more toxic aldehydes than the safe daily limit set by the World Health Organisation. via FoodMatters
The average recipe for deep frying calls for temperatures between 320°F and 375°F…
The Best Oils To Use
The experiment showed that coconut oil produced the lowest levels of aldehydes, while corn oil and safflower oil produced three times more aldehydes than butter (1).
What You Should Do Instead…
In the past individuals were told to opt for vegetable oils instead of animal fats due to their cholesterol clogging effects.
Through a great deal of in-depth study and analysis, it has been determined that this is only true of vegetable oils in their natural states, prior to heating.
The act of heating vegetable oils forces them to undergo chemical changes, which can lead to carcinoma, cardiac disorders, and negatively affect your cognitive abilities when ingested (2).
The best practices are using oils derived from animal fat, such as butter or ghee if high temperatures are required.
And use coconut or olive oil for recipes that don’t require extreme heat. But most importantly, eliminate most, if not all, fried foods from your diet.