Cooking with lard or butter is said to have numerous detrimental effects on health. With this information, vegetable oils have become the top pick for chefs, moms and other people who cook and prepare food for their families and friends.

In a latest study, however, scientists from the De Montfort University Leicester (DMU) said that cooking with vegetable oils may not be as healthy as people believe because it releases agents that can cause cancer. The researchers even put the preference back to lard or butter as a better option.

For the study, the participants were given vegetable oil, sunflower oil, corn oil, olive oil, cold-pressed rapeseed oil, goose fat, lard and butter to be used for daily cooking. They then collected the leftovers from the used oil and sent it back to the researchers for analysis.

The findings of the study showed that oils and fats change its molecular composition when heated and produce substances called aldehydes, which may cause cancer and heart disease.

The researchers used millimoles as a unit of measurement and in their investigation, it was found that heating coconut oil at high temperatures for about half an hour could release approximately half a millimole of toxins. Butter released over one millimole and sunflower oil discharged more than five millimoles.

The amount of aldehydes released by sunflower and corn oil was said to be 20 times higher than the prescribed level of the World Health Organization. Olive oil and rapeseed oil generated significantly lower amounts of aldehydes as goose fat and butter. "The reason being that these fats are richer in monounsatur[at]ed and saturated fats, and are much more stable when heated," said Michael Mosley, the presenter of the case at BBC 2, which featured the study on July 29, 2015.

Martin Grootveld, professor of bio-analytical chemistry and chemical pathology at DMU, now recommends using olive oil for cooking. He explained that this is due to the minimal levels of toxins produce, as well as the fact that the compounds produced are less hazardous to the body.

"Sunflower and corn oil are fine as long as you don't subject them to heat, such as frying or cooking," Grootveld said. He further explained that the study presented a simple chemical idea that something once believed to be healthy turn out to be unhealthy at conventional frying temperatures.

Photo: Andrew Malone | Flickr