Spanish researchers have released a study suggesting that using olive oil to fry food is not any more harmful than using other oils, and it may in fact be safer.

There is a widespread belief that frying food in vegetable oils could be harmful to health due to aldehydes, toxic chemicals that are produced in the process, according to an Olive Oil Times report on 6 July.

Aldehydes are organic compounds that contain a carbon-oxygen double bond, which are found naturally in the human body, but consuming excessive amounts of them could contribute to ailments such as diabetes.

Now, scientists at the University of the Basque Country in Spain have performed a study on olive, sunflower and flaxseed oils, measuring their aldehyde content after heating the oils to 190°C.

The results of the study showed that sunflower and flaxseed oils, which are polyunsaturated, produced higher amounts of aldehydes at a faster rate than olive oil, which is monounsaturated.

The research team suspected that the reason behind olive oil’s lower aldehyde content was that polyunsaturated oils contain more regions for chemical reactions than olive oil, which could indicate that olive oil is a safer option for frying food.

However, scientists had so far researched the effects of high aldehyde doses on animals and not humans, and therefore the Spanish team said it was too early to draw conclusions from the study.

Some experts had argued that the risk in frying depended also on the quality and freshness of the oil used and on how hot it was allowed to get, wrote the Olive Oil Times.

As a general rule of thumb, frying foods in shallow amounts of olive oil for short periods was unlikely to lead to aldehyde exposure, while any oil heated beyond its smoke point would contain harmful chemicals.