Who doesn’t love a good grilled asparagus, blackened tilapia or seared chicken? But not too seared – after all, burnt food gives you cancer, right?
Well, not exactly. The idea that burnt food contains toxic, cancer-causing carcinogens has been floating around for about 20 years, fuelled time and again by headline-hungry news coverage that sometimes seems to misunderstand the research.
Let’s start with the science. There are three chemicals that have raised nutritional eyebrows when it comes to cooked food and cancer: acrylamide, which is found in cooked, high-carb foods like baked potatoes and toast; and heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), which are found in meat that has been cooked using high-heat methods, such as frying and barbecuing.
To sum up: acrylamide is found in cooked carbs, HCAs and PAHs are in cooked meat, and people think all three are bad. But are they?
Acrylamide is toxic. Serious research into its effects only began after a bunch of cows in Sweden died after drinking from a contaminated stream near an industrial site that used it in adhesives. But the operative word here is industrial. The levels found in cooked food are much, much lower. As for whether burnt foods actually cause cancer or other ill effects in humans, the jury is out. A 2015 report claimed there was no apparent link to cancer, except for maybe a small connection to certain types of kidney, endometrial and ovarian cancers. But even these potential risks disappear if you don’t cook high carb foods past a nice, mild yellow colour.
To sum up: baked potatoes and toast are a-OK, especially if you don’t cook them past golden brown.
Now on to PAHs and HCAs, which form when meat fat comes into direct contact with flames, extremely high heat surfaces like grills, or boiling oil. Should we give up BBQ and fried chicken?
Again, the jury is still out. A link between these chemicals and cancer has been shown in animals, but only in extremely high doses far beyond what a person would consume. There is no evidence yet linking PAHs and HCAs with cancer in humans.
(A piece of side advice: many food scares are based on studies in which the poor test animals have been dosed with so much of a chemical that they couldn’t not get sick, which is why it’s always important to check the research before you jump onto the bandwagon.)
This isn’t to say that these chemicals definitely don’t cause cancer – only that a link hasn’t really been shown in humans consuming normal amounts. On the other hand, humans have been cooking food over a fire since the dawn of time, so how bad could it be?
If you’re really worried, there are some simple things you can do: don’t burn your toast and cut back on fried, grilled and roasted meat in favour of boiled, which doesn’t contain PAHs and HCAs. And, finally, eat more vegetables – which we should all do anyway!