With all the choice out there – what oil should we be cooking with? I had no idea really, so I decided to do some research – and share it with you! I’m sure I’m not the only one that wants to avoid harmful side effects from cooking with the wrong oil… And it looks like choosing the right oil to cook with is a complicated business! And it’s all so confusing! As usual there is a lot of contradicting information out there. Partly because science has moved on recently in this field and found new evidence of some oils being harmful when heated.
I’m not sure if you’ve watched “Trust me I’m a Doctor” before. But they do some interesting experiments there. And they did one on oil as well. They asked volunteers to cook with different oils and then tested the samples of the cooking oil afterwards to see how many harmful substances had been created. When you are frying or cooking at a high temperature (at or close to 180C or 356F), the molecular structures of the fats and oils you are using change. They undergo what’s called oxidation – they react with oxygen in the air to form aldehydes and lipid peroxides. At room temperature something similar happens, though more slowly. When lipids go rancid they become oxidised. Consuming or inhaling aldehydes, even in small amounts, has been linked to increased risk of heart disease and cancer.
And I found the results of this experiment very surprising. It showed that actually our grannies were right all along! They cooked with goose fat or butter, ghee or coconut oil, depending on where they came from. It was the food scientists who scared us away from cooking with certain fats that got it wrong.
According to the programme’s experiment (and there is other scientific research supporting these findings), the worst oils to be frying with are sunflower and corn oils! We should be using olive oil, butter and lard instead. Actually the best to use at high temperatures is coconut oil. I had no idea! The combination to look out for is oil or fat high in monounsaturated or saturated lipids (preferably greater than 60% for one or the other, and more than 80% for the two combined), and low in polyunsaturates (less than 20%). Here is a handy little breakdown of oils and their components:
Also good to know is that extra-virgin olive oil is high in antioxidants called polyphenols that have been linked to heart health. And if you (like me) are worried about coconut oil being too strong a flavour when frying – I’ve actually tried it and have found that our food tasted no different. So keep coconut or a similar saturated fat for heavy frying, olive and rapeseed oils for light frying and salads, and pumpkin and avocado oils for dressings and dips.
But actually the best thing to do is to try and do less frying in the first place. Particularly at high temperature. If you are frying, minimise the amount of oil you use, and also take steps to remove the oil from the outside of the fried food, perhaps with a paper towel.
There you go. I hope you found that helpful. I certainly did. I shall not be buying those big tubs of frying oil anymore and replace them with coconut oil instead. As well as stop reusing frying oil. Yes it seems like a waste when we deep fried something, but actually our health is way more important than saving a few pounds on reusing oil!