LONDON: Acrylamide is a chemical used in the manufacture of plastics and the treatment of water. It is also carcinogenic. But what nobody knew until recently was that it occurs at dangerously high levels in baked and fried foods such as chips, crisps and breakfast cereals. So should we worry?

Frankly, I’ve had enough of alarmist stories about food. For the past 14 years I have dutifully imposed every successive food fad and contradictory piece of dietary advice on my household, and my energy for it is more or less exhausted. We were vegetarian, until assured that babies needed meat; red-meat-eaters, until BSE sent us back to chicken in a panic; redmeat-avoiders, until my pale and listless children were diagnosed as iron-deficient; fish enthusiasts, until the discovery of dioxins in fish, and the solemn warnings that no one should eat fatty fish more than twice a week. We drank less tea, because it was full of caffeine, before being told to drink more of it, because it was full of antioxidants. Surely it was healthy to eat fruit and vegetables? Yes, provided they didn’t come from the store I had been going to for the past three years, where the delicious flavours were perhaps due to the fact that 80 per cent of the products were contaminated with pesticides.

So when I read newspaper reports this spring that Swedish scientists had discovered a probable carcinogen called acrylamide in baked and fried food, I turned the page hastily and hoped the story would disappear. Which it did — for a couple of months. There were no health warnings on crisp packets; the biscuit companies were still in business. Then the World Health Organization announced that it was convening an unprecedented and urgent meeting of leading food scientists to discuss the Swedish findings. One of the British scientists who attended, Professor Peter Farmer of Leicester University, warned that this was not just another food scare. “The risk is unknown, but it could be on a par with tobacco.” I started to pay attention.

Acrylamide is a genotoxic carcinogen that causes damage to the nervous system, and is listed as “probably” carcinogenic to humans. A chemical used in the manufacture of plastics, it is also present in tobacco smoke, and is used in the treatment of drinking water. The US Environmental Protection Agency considers it potentially so dangerous that it has fixed the safe level for human consumption at almost zero. The maximum permissible level of acrylamide in American drinking water is 0.5 parts per billion, or 0.5 micrograms per litre.

Now the Swedish scientists had discovered something that no one had ever suspected: that acrylamide was present in some baked and fried foods, and at levels that made nonsense of the limitations on water. A large portion of French fries from one local fast-food company contained at least 300 times the amount of acrylamide permitted in a single glass, while one sample of McDonald’s French fries had double that amount. Potato French fries contained acrylamide in even higher concentrations. But it wasn’t just fried food that was a problem. Some crispbreads, cereals and biscuits had much higher levels than some kinds of chips. And acrylamide was present, although at much lower levels, in all breads. The average figures for some of the products tested, in micrograms per kilogramme, were: soft bread, 50; rye bread, 89; cornflakes, 53; Rice Krispies, 247; popcorn, 416; French fries, 450; crackers, 547; potato French fries, 1,200, and Ryvita, 1,200 to 1,800. Cooked meat had far lower levels: fried chicken contained 39, and meatballs 64. But raw and boiled foods had no traces of the chemical.

The discovery had come about by chance. Five years earlier, workers building a tunnel in the south of Sweden had suffered neurological damage from exposure, after an accident, to the acrylamide being used in the process. A Swedish university group that was studying the men in the aftermath of the accident was startled to find inexplicably high levels of acrylamide in the blood of its control group. Dr Margareta Tornqvist, who was leading the study, investigated dozens of possibilities before testing food.

The results were totally unexpected and, when they were published, Sweden went into shock. The media were dominated by the news, and shares in one crisp manufacturer immediately fell almost 15 per cent. The news had a powerful impact, because the tunnel-poisoning scandal meant that everyone in the country was already aware of acrylamide’s harmful potential.

The Food Standards Agency in Britain says that the revelation poses an entirely new and global problem. Most food scares are about contamination. There is no frame of reference for dealing with a cancer-causing chemical which is produced during the normal cooking process, and which appears in foods that most people eat every day. Dozens of foods haven’t yet been tested, so no one can yet be sure which pose the greatest risks. Research is urgently needed into how and why acrylamide is formed. The WHO has recommended the creation of an international network to conduct research, and the EU commissioner in charge of food has been asked to start coordinating a European response.

In the interim, it is the Swedes who are still leading the way. In the past few weeks, Tornqvist has found that grated, microwaved potatoes contain acrylamide levels that are higher than that of most French fries. And vegetables — not part of the original tests — are producing acrylamide at high levels, too. Frying spinach produces 112 micrograms per kilogramme, and fried beetroot produces one of the highest levels — 890.

Leif Busk, the head of research at Sweden’s National Food Administration, says it is clear that the crucial factors in the formation of acrylamide are heat and time. Boiled food is completely safe. But once food is heated at temperatures above 120 degrees Centigrade, acrylamide can start to form, and the longer the cooking process, the higher the acrylamide count. Well-cooked toast has twice the acrylamide of lightly toasted bread. When oven French fries are briefly cooked, they contain 301 microgrammes; overcooked, they contain an astonishing 1,104.

Busk and his team are developing a hypothesis that may explain what is happening. From the start, the scientists were intrigued that the same kinds of foods were producing a wide range of results. Fourteen different types of crisp produced results ranging from 330-2,300 microgrammes per kilogramme. Some cereals scored less than 340; others more than 1,400. Busk thinks the answer may lie in sugars, and in what happens to them when they are cooked.

All carbohydrates form sugars when they are broken down by heat, but different kinds of carbohydrate produce different types of sugar, and some may form acrylamide much more easily than others. The precise chemical composition of a potato, or any other vegetable or cereal, will be influenced by its variety, the soil in which it is grown, and how it is fertilised. The sugar theory would explain why beetroot, which is high in carbohydrate, forms far more acrylamide than spinach, which is relatively low. It also offers the hope that farmers and manufacturers might, in time, be able to identify and produce low-acrylamide food.

That’s crucial, because no one involved in food safety or nutritional research holds out much hope that consumers will change their eating habits if acrylamide is proved to be dangerous. Spokesmen at WHO and America’s Centre for Science in the Public Interest point out wearily that although a third of all cancers are already assumed to be caused by diet, two decades of advice on healthy eating have produced only marginal improvements in our eating habits, while obesity and cancer rats are still rising.

But should any concerned consumer care about acrylamide? Do all the figures on intake add up to real personal risk? Everyone agrees that there needs to be more understanding of precisely how acrylamide affects the human body, and until there is, the FSA refuse to offer any estimates. But while Swedish scientists await permission to conduct controlled trials on humans, they have made extrapolations based on that standard human substitute, the rat. They calculate that in Sweden the average intake of acrylamide from all sources is 70 micrograms per day, which translates as one microgram per kilo of body weight per day. At that level, they calculate that one person in 100 will be killed by acrylamide, or to put it another way, that 6,000 deaths a year in Britain could be ascribed to it.

One in 100? I told Busk that, at those odds, it didn’t seem worth telling my children that they had to give up a lifetime of delicious French fries, not to mention fried beetroot. He had several serious responses to that. First, countries will have average intakes much higher than Sweden’s, with correspondingly higher risks. In Sweden, most potatoes are boiled or baked, and it’s rare to find someone who eats French fries or potato French fries every day. In Ireland or Scotland, for example, that is commonplace.

Second, dietary analysis shows children and teenagers to be the highest consumers of cereals, snacks and fried foods, and with that, acrylamide. Not only will their intake of the “probable” carcinogen be relatively higher than that of adults, but they are more likely to be damaged by it, because their cells are dividing more rapidly, and acrylamide is known to affect dividing cells. A single 40g packet of potato French fries per day could, for instance, take a child over the one microgram per kilo per day on which the average risk is calculated — and that is before they have eaten anything else.

Third, Busk points out, their research indicates that acrylamide is 1,000 times more dangerous than the majority of carcinogens found in food. Every single time you consume it, your DNA is being damaged, and every increase in the dose is an increase in risk. If you don’t care about limiting acrylamide intake over a lifetime, then it is perverse to worry about pesticides, or dioxins in fish.

In the end, though, can the acrylamide issue be so urgent, when all that has happened is the exposure of a risk which has always been there? Plenty of people think that the issue is being overblown, and not all of them are representatives of the food industry. Dr Walter Willett, a food scientist at Harvard, thinks the Swedes have made their research public at far too early a stage. He wants to see more hard evidence, an abandonment of extrapolations from animal studies, and a recognition that there’s no need to be deeply concerned, because we have been eating this way for thousands of years.

On this last point he, and many other critics, may be wrong. The techniques of grilling, baking and frying may have been around for ever, but in most societies they were never used as frequently as they are now. Forty years ago, the distinguished anthropologist Claude Levi-Strauss observed that all traditional societies boiled their everyday food. Roasting and frying were reserved for celebrations, guests, and the upper classes. And when I think back to the limited experience of my own childhood, I can see how drastically cooking habits have changed. My mother fried all her rice, sauteed vegetables and baked lasagnes, but my English grandparents (born 1899) boiled practically everything they ate. They lived on porridge, mashed potatoes, boiled beef and boiled ham, and even Sunday roasts were effectively steamed in covered dishes. If they had a frying pan, I never saw it, and their acrylamide intake was probably limited to toast, and a cracker with the cheese.

Where does that leave the rest of us? So many questions are still unanswered. More foods need to be tested, including the staples consumed in the rest of the world, while researchers point out that no one knows enough about cooking patterns at home. Britain’s FSA has so far advised people not to change their diets. I’m not going to wait for them to change their minds; I have stopped buying my children potato French fries, or crispbreads, and will severely ration French fries, but bread is too delicious and too nutritious to be abandoned. I’ll still bake potatoes, because the water inside them apparently means that the interior is steamed at 100 degrees Centigrade, but I ought to discard the crisp, carcinogenic skin. Meanwhile, I predict that the first person to publish the Awfully Boring Acrylamide Cookbook, or How To Make Boiled Food Fashionable, Interesting and Delicious, will find themselves with a mini hit on their hands in 2003.—Dawn/The Guardian News Service.