Cooking with vegetable oils releases toxic chemicals linked to cancer and other diseases, according to leading scientists, who are now recommending food be fried in olive oil, coconut oil, butter or even lard.
Scientists found that heating up vegetable oils led to the release of high concentrations of chemicals called aldehydes, which have been linked to illnesses including cancer, heart disease and dementia.
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.
Cheap vegetable oil made from seeds (canola, sunflower, corn, safflower, grapeseed, rice bran and soybean oils) is a new addition to the human diet. Unlike animal fats and oils made from fruit (olive, avocado and coconut oils), they’re very high in polyunsaturated fats and in particular something called an omega-6 fat.
A recent study found that when seed oils containing these fats are heated at a normal cooking temperature (of 180 degrees celsius), they create highly toxic chemicals known to be involved in cancer causation.
Each time the oil was re-used the concentration increased massively. The study showed that by the fifth day of oil re-use, it had five times the concentration of these chemicals that it had on the first (which was already alarmingly high).
But worse than that, the researchers also made the point that all they could measure was the amount of these chemicals left in the oil. Since they are highly volatile, they are constantly escaping into the air around us when the food is being cooked.
According to another recent study, it is likely that this volatility explains the stubbornly high rates of lung cancer among women in Asian countries (where smoking is rare among women, but wok frying with Canola oil is a daily task).