A study done by Prof Grootveld and his team, on which oils and fats are best to cook with, has revealed olive oil as the winner. Due to the ongoing debate about which fats are healthy and which are harmful, the study focused on sunflower oil, vegetable oil, corn oil, cold pressed rapeseed oil, olive oil (refined and extra virgin), butter and goose fat. These fats and oils were tested by the team and they discovered that when heating these oils to frying temperatures, the molecular structure of the fats and oils changed and undergo oxidation. This process of oxidation forms aldehydes. Consuming or inhaling aldehydes has been linked to cancer as well as increased risk of heart disease.
Prof Grootveld and his team found that sunflower and corn oil generated very high levels of aldehyde, while olive oil and cold-pressed rapeseed oil produced far less aldehydes, as did the butter and goose fat. The reason is that these oils are richer in monounsaturated and saturated fatty acids, and these are much more stable when heated.
According to Grootveld, while the use of lard for frying is better than that of sunflower or corn oil, olive oil is generally best for frying or cooking. “Firstly because lower levels of these toxic compounds are generated, and secondly the compounds that are formed are actually less threatening to the human body”
It has also been found by the study that when it comes to cooking it doesn’t seem to matter whether the olive oil is “extra virgin” or not. “The antioxidant levels present in the extra virgin products are insufficient to protect us against heat-induced oxidation.”
Grootveld also recommend using less oil when frying, keeping the method of frying, especially at very high temperatures, to a minimum and storing oils in a dark cupboard, away from sunlight.
According to Prof Grootveld:
…the ideal ‘compromise’ oil for cooking purposes is olive oil.