At the end of the blog yesterday that suggested that too much soy bean oil in our diet is not a good idea we asked what should we be frying with then?
Well, it seems that the BBC has also been considering this question (albeit for a different reason). Published in the magazine part of their website is an article in which they have given people different oils to shallow fry their foods in and then collected the oils for analysis. The oils included “sunflower oil, vegetable oil, corn oil, cold pressed rapeseed oil, olive oil (refined and extra virgin), butter and goose fat.”
So what were they looking for? Oxidisation products called aldehydes and lipid peroxides. Basically, when you heat up the oil it reacts with oxygen in the air. This also occurs at room temperature but a lot slower. Aldehydes are toxic and can react with our proteins, enzymes and hormones which can seriously affect our health.
And what did they find? Sunflower oil and corn oil, rich in polyunsaturates (so normally thought to be very good for us) generated very high levels of aldehydes. The olive oil, goose fat and lard produced far less aldehydes. This is not the first time this has been reported, a quick google and you will find quite a few publications form the last two years looking at these oils and the effects of frying.
But don’t get put off sunflower and corn oil over this. Prof Grootveld who carried out the testing is quoted in the article as saying that these oils are still good for you, just don’t heat them up too much. So I guess that means you can still keep them in your salad dressings then. And until I hear anything more, I’ll be frying my omelettes in olive oil or butter and the coconut oil can stay on the shelf.