‘Killer spuds’ cancer warning sparks risk row

Dark sides: The browning of crispy roast potatoes also produces the chemical acrylamide.

Do roast potatoes, burnt toast and crisps really cause cancer? The British government has launched a campaign advising people to cut down. Many have ridiculed it as a ludicrous exaggeration.

‘If you want to stay healthy, don’t brown your toast’ advised the front page of The Times yesterday. ‘Cancer risk in crispy roast potatoes’ warned The Express. ‘YOU’VE HAD YOUR CHIPS’ declared The Sun in three-inch block capitals, before explaining: ‘boffins link fries to cancer — pizza, toast are killers too’.

The increasingly alarming headlines were all thanks to new guidelines by the Food Standards Agency (FSA) in the UK, which were launched yesterday. They relate to a chemical called acrylamide which is released when starchy foods like toast, potatoes and doughnuts are cooked for too long at high temperatures. The more brown the foods become, the more acrylamide is present. And high levels of the chemical have been found to cause cancer in mice — so scientists believe there could be a risk for humans too.

That does not mean you should swear off roast dinners for life, says the FSA. But you should try not to brown your starchy foods; instead you should ‘go for gold’.

There is just one problem. So far, says Cancer Research UK, there is no strong evidence linking acrylamide and cancer. For one thing, studies with mice are not the same as studies with people. And while the chemical is officially listed as a ‘probable carcinogen’, most people do not consume enough for it to have an effect; it would take 320 slices of burnt toast a day to really be at risk.

In light of all this, telling people it causes cancer is ‘a dumb thing to say’, said the celebrity chef Raymond Blanc. Or, as a Cambridge professor put it, ‘many things in life may increase risk, but it’s the size of the risk that makes it important.’

By the end of the day, many of the same newspapers which had warned against burnt toast in the morning were explaining why it was okay after all.

Hot potato

Starchy foods may not be as bad as smoking cigarettes, says the FSA, but scientists still think there is a small risk to overcooking them — and they have a duty to tell people that. They never said that anyone should give up potatoes, just that they should cook them carefully to be on the safe side. This is why scientists do this kind of research in the first place: to find out the facts, and let people make informed decisions about their health.

Enough, say the campaign’s critics. Don’t we have enough to worry about without adding potatoes to the list? Red wine, chocolate, kale — it feels like every other day, there is another study giving dubious advice about what we should or should not eat to stay healthy. All these reports just end up confusing people or scaring them for no reason. Worse still, they reduce the impact of genuine scientific food advice: all you need is a balanced diet .

You Decide

  1. Was the FSA wrong to warn people about browned potatoes?
  2. Are we given too much advice about food in general?


  1. Create a poster which gives nutritional advice to the average teenager. Include evidence explaining the science behind each claim.
  2. Conduct your own experiment by following the government’s food guidelines for a week and tracking how it effects your mood. Present your findings to the class.

Some People Say...

“The four most dangerous words: A new study shows…”

John Arnold

What do you think?

Q & A

Should we really not trust scientific advice?
It is worth being sceptical. Not because scientists are lying or bad at their jobs, but because their findings can be misrepresented to seem more exciting than they actually are. This is made worse if their study is picked up by journalists, who are more likely to write headlines about burnt toast than balanced diets.
How do I know what’s true?
Read beyond the headline and try to understand the science on which the advice is based. In this case, the fact that the studies involved mice rather than people made them less certain. If a study has a small sample size (less than 1,000 people) then it is less reliable too. And if you are still unsure, research whether other studies have produced similar results — that would make them more trustworthy.

Word Watch

Food Standards Agency
A government body in the UK which provides information and food advice to the public.
The chemical is produced when water, sugar and amino acids in food are combined during the cooking process. This also changes the food’s colour, and creates new flavours and aromas — such as the distinctive burnt toast smell, or the flavour of crispy roast potatoes.
A substance which causes cancer. Acrylamide is listed as ‘probable’ by the IARC (International Agency for Research on Cancer). This means there is limited evidence for its effect on humans, but strong evidence using animals.
320 slices
The studies on acrylamide found adults with the highest rates of the chemical could consume 160 times more without being seriously at risk (or 320 slices of toast a day).
In 2011, a study looked at 111 articles making ‘dietary health claims’ in the top ten British newspapers during a single week. It found that between 72% and 68% of the articles were based on ‘uncertain’ science, which could be causing ‘misconceptions’ about food.


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