It’s not just red meats under the microscope. One of the long-recommended items for good health, polyunsaturated vegetable oils are now under fire, with experts saying that we should be frying our food in olive oil, coconut oil, butter or lard in preference over corn or sunflower oil.
The results from a series of experiments at De Montfort University Leicester have been released turning upside down the previous advice on the use of the products. The experiments showed that that heating of these kinds of polyunsaturated vegetable oils released high concentrations of aldehydes that have been known as causing cancer, heart disease and dementia.
And it all comes back to reframing the way we eat to cause less cancer.
Martin Grootveld, a professor of bioanalytical chemistry and chemical pathology, said in The Telegraph 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.
“Sunflower and corn oil are fine as long as you don’t subject them to heat, such as frying or cooking. It’s a simple chemical fact that something which is thought to be healthy for us is converted into something that is very unhealthy at standard frying temperatures,” he said.
In his studies, volunteers were given sunflower oil, vegetable oil, corn oil, cold-pressed rapeseed oil, olive oil, butter, goose fat and lard and asked to use them in every day cooking. They collected any leftover oil and sent it to DMU’s labs to be analysed.
Professor Grootveld’s team found sunflower oil and corn oil produced aldehydes at levels at least 20 times higher than recommended by the World Health Organisation. Olive oil and rapeseed oil produced far fewer aldehydes as did butter and goose fat.
Not only that, but Professor Grootveld’s team also identified two previously unknown aldehydes in the samples of these oils – a world first.
He recommends olive oil for frying or cooking: “Firstly, because lower levels of these toxic compounds are generated, and secondly the compounds which are formed are less threatening to the human body.”
What do you fry with?