What’s the Deal with Toast and Cancer?

Burnt toast and well-roasted potatoes may increase the risk of cancer, and according to British public health officials, we should avoid eating them. But just how worried should we be?

On Monday, the United Kingdom’s Food Standards Agency (FSA) launched their “Go for Gold” campaign, encouraging families to aim for a golden yellow color when cooking starchy foods, like bread and root vegetables, and avoid over-browning.

Burnt toast contains a carcinogen called acrylamide.

The campaign hopes to minimize exposure to a potentially harmful chemical called acrylamide, a natural compound that forms when starchy foods are baked, roasted, fried, toasted, or grilled above 250˚ F. Higher cooking temperatures and longer cooking times can further increase levels of acrylamide.

Aside from bread and potatoes, acrylamide is found in coffee, crackers, and cereal-based baby food. It can also be found in tobacco smoke and various industrial sealants.

Previous studies in mice have shown that high doses of acrylamide can heighten the risk of neurological damage and cancer in animals. Human studies have delivered incomplete or inconsistent results, but taken as a whole, they have led experts to believe the chemical could likely have the same effect. The International Agency for Research on Cancer considers acrylamide a probable human carcinogen.

While evidence of human cancer risk has yet to be proven, FSA research shows that people in all age-groups are consuming more than what experts are comfortable with. They argue that it’s better to be safe than sorry. Here’s Haroon Siddique, reporting for the Guardian:

FSA director of policy Steve Wearne said: “You can’t point to individual people and say that person has cancer because of the amount of acrylamide in their diet but because the mechanisms by which it does have this effect in animals are similar to the mechanisms you would expect to occur in humans it’s not something we can ignore.”

But some experts have found the public campaign unnecessary and the dangers of acrylamide overly dramatized. Cancer Research UK, while acknowledging the potential risks of over-browning certain foods, found “there is no strong evidence linking acrylamide and cancer.” The organization found multiple well-established risks including obesity, smoking, and drinking to be much more pressing.

Here’s David Spiegelhalter, writing for the Winton Centre for Risk and Evidence Communication at the University of Cambridge:

Cancer Research UK say that “researchers estimate that overweight and obesity are behind around 18,000 cases of cancer each year in the UK.” In stark contrast, the FSA provide no estimate of the current harm caused by acrylamide, nor the benefit from any reduction due to people following their advice.

Some exposure to acrylamide is inevitable, and in a nod to reality, the FSA does not recommend that people abandon potatoes or bread altogether. Since most people are unaware of the dangers—or even presence—of acrylamide in foods, the FSA says their campaign aims to increase public awareness and share simple steps to reduce acrylamide consumption including:

  • Aim for a golden yellow color or lighter when cooking starchy foods
  • Avoid over-heating packaged foods by carefully following cooking instructions
  • Eat a balanced diet
  • Store raw potatoes in a cool, dark place as opposed to the fridge which can increase overall acrylamide levels

The FSA says that while the risk is not significant, it is one that can be easily reduced. “We are not saying to people to worry about the occasional piece of food or meal that’s overcooked. This is about managing risk across your lifetime,” Wearne told the Guardian.