Chips as deadly as cigarettes
Nov 18, 2002
Acrylamide is a chemical used in the manufacture of plastics and the treatment of water. It is also carcinogenic
Acrylamide is a chemical used in the manufacture of plastics and the treatment of water. It is also carcinogenic.
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.
There are alarmist stories about food. For the past 14 years I have imposed every successive food fad and contradictory piece of dietary advice on my household.
We were vegetarian, until assured that babies needed meat; red-meat-eaters, until BSE sent us back to chicken in a panic; red meat-avoiders, until my pale 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, provided they did not come from the store whose flavours and products were contaminated with pesticides.
So when I read newspaper reports 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.
There were no health warnings on crisp packets; the biscuit companies were still in business. Then the World Health Organisation announced that it was convening an urgent meeting of leading food scientists to discuss the Swedish findings. Professor Peter Farmer of Leicester University, one of the British scientists who attended, warned that this was not just another food scare. “The risk is unknown, but it could be at par with tobacco,†he said. 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. It is a chemical also present in tobacco smoke.
The US Environmental Protection Agency considers it 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 chip.
Acrylamide was present, although at much lower levels, in all types of bread. The average figures for some of the products tested, in micrograms per kilogram, 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 after the accident was startled to find 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 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%. The Food Standards Agency in Britain says that the revelation poses a 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.
Many foods have not yet been tested, so no one can yet be sure which pose the greatest risks. Research is 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 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 Adminis-tration, 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 C, 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 micrograms; overcooked, they contain 1,104.
The scientists also discovered that 14 different types of crisp produced results ranging from 330-2,300 micrograms 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.
Do all the figures on intake add up to real personal risk? Everyone agrees that there needs to be more understanding of 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, that 6,000 deaths a year in Britain could be ascribed to it.
Dietary analysis shows children and teenagers are 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.
However, more foods need to be tested, Researchers point out that no one knows enough about cooking patterns at home.
Guardian Newspapers
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.
There are alarmist stories about food. For the past 14 years I have imposed every successive food fad and contradictory piece of dietary advice on my household.
We were vegetarian, until assured that babies needed meat; red-meat-eaters, until BSE sent us back to chicken in a panic; red meat-avoiders, until my pale 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, provided they did not come from the store whose flavours and products were contaminated with pesticides.
So when I read newspaper reports 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.
There were no health warnings on crisp packets; the biscuit companies were still in business. Then the World Health Organisation announced that it was convening an urgent meeting of leading food scientists to discuss the Swedish findings. Professor Peter Farmer of Leicester University, one of the British scientists who attended, warned that this was not just another food scare. “The risk is unknown, but it could be at par with tobacco,†he said. 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. It is a chemical also present in tobacco smoke.
The US Environmental Protection Agency considers it 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 chip.
Acrylamide was present, although at much lower levels, in all types of bread. The average figures for some of the products tested, in micrograms per kilogram, 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 after the accident was startled to find 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 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%. The Food Standards Agency in Britain says that the revelation poses a 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.
Many foods have not yet been tested, so no one can yet be sure which pose the greatest risks. Research is 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 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 Adminis-tration, 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 C, 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 micrograms; overcooked, they contain 1,104.
The scientists also discovered that 14 different types of crisp produced results ranging from 330-2,300 micrograms 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.
Do all the figures on intake add up to real personal risk? Everyone agrees that there needs to be more understanding of 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, that 6,000 deaths a year in Britain could be ascribed to it.
Dietary analysis shows children and teenagers are 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.
However, more foods need to be tested, Researchers point out that no one knows enough about cooking patterns at home.
Guardian Newspapers