Last night I heated some extra virgin olive oil and fried chopped potatoes, onion and asparagus. After a few moments I tossed in some spinach leaves and chopped tomato, then poured over beaten eggs. A sprinkle of cheese and a light grill to brown the top and voila – yummy frittata for an easy Sunday evening meal. The big question is have I increased my risk of getting cancer by frying in olive oil?

“Exposure to second-hand cigarette smoke or going outside without sun-block is much more likely to cause cancer than burning your cooking oil,” writes fats and oils expert, Laurence Eyres, in the October/November issue of Food New Zealand – the official journal of the NZ Institute of Food Science and Technology. But what about all those cancer causing chemicals – polycyclic aromatic hydrocarbons – that are formed when we burn cooking oil? It’s true that when oil is repeatedly heated to its smoking point it will begin to accumulate cancer causing substances and lose its natural antioxidants. But who uses the same oil over and over again, especially when we’ve burnt it? We usually just heat and eat.

When researchers feed ‘severely heat-abused frying fats’ (more than we would ever do at home) to some poor experimental animals there are ‘very few deleterious effects’. In fact olive oil is especially stable because it is monounsaturated. Extra virgin olive oil is even better than a lower quality olive oil because it has more natural antioxidants to soak up nasty free radicals. And good news for those of us who love New Zealand extra virgin olive oil. Compared to overseas olive oils it has more antioxidants and a higher smoking point, so you can heat it hotter before it starts to burn.

As Laurence Eyres states, “The urban myth that heating extra virgin olive oil when cooking can cause cancer is not founded on scientific fact.” Great! I’ll keep using extra virgin olive oil and when I don’t want that distinctive olive flavour, for example in my muffins or carrot cake, I’ll use monounsaturated canola oil.

Oils and Fats Specialist Group (NZ)