Toxic acrylamide is formed when starchy foods like potatoes are cooked at high temperatures. How and why this happens isn't fully understood, reports Ali Bracken
A fan of chips or salty crisps? That's okay, say the experts, but don't over-indulge - particularly in crispy fries - as a threat looms that such foods are high in acrylamide, a toxic industrial chemical that has been shown to cause cancer in animals. Certain doses are also toxic to the nervous system of both humans and animals and, as a result, acrylamide has been labelled a possible carcinogen and neurotoxin since it was discovered in food in Sweden in 2002.
Acrylamide is industrially manufactured to make polyacrylamide materials used drinking-water and waste water treatment, glues, paper and cosmetics.
The chemical is also produced during frying, baking and toasting of a variety of foods, particularly starchy foods like potatoes and cereals, as well as in coffee. The Food Safety Authority of Ireland (FSAI) recommends that people have no more than four cups of coffee a day to lessen the possible risk of acrylamide.
A hysterical public reaction followed the 2002 discovery of acrylamide in food, says Dr Ronan Gormley of Teagasc's National Food Centre, which, in conjunction with UCD, is currently researching what leads to the formation of acrylamide in potatoes. But this has since calmed and we are still somewhat in the dark about whether it poses a carcinogenic threat, he says. The key now, he adds, is public awareness.
"If your french fries are very dark from heavy frying, the chances are that they are high in acrylamide . . . Because the surface area of crisps is even bigger, you are likely to get even more acrylamide," says Dr Gormley. But a small amount of acrylamide isn't too bad, just don't overdo it, he stresses, because we don't yet know the potential health risk. Would two packets of crisps a day be too high an intake of acrylamide?
"Well, it certainly wouldn't be a great idea for a small child for reasons of salt and fat as well as acrylamide."
Janis Morrissey, dietician with the Irish Heart Foundation, says they are concerned with the levels of fat and salt intake Irish children consume.
"Evidence from our national surveys is that crisps would be one of the common snacks for children."
The most recent Health Behaviour in School Children (HBSC) survey carried out in 2002 found that 25 per cent of boys eat at least one packet of crisps a day and girls consume even more, with 27 per cent having at least one packet a day, says Ms Morrissey. The survey, of children between 10 and 17 years old, is conducted every four years by the Centre for Health Promotion Studies at NUI, Galway.
The chips we buy from chip shops have been pre-conditioned - the potatoes have been stored at the right temperature to ensure low sugar levels which in turn reduces acrylamide - but the problem lies with our homemade chips, says Dr Gormley, because we don't necessarily condition potatoes at the appropriate eight degrees temperature.
The project currently underway by Teagasc and UCD is a risk assessment of acrylamide in potatoes in Ireland. Dr Gormley expects it to conclude by next February. One possible outcome may be the recommendation of frying protocols. Acrylamide is associated with starchy foods but its formation is not directly related to starch. Rather its formation is largely due to the reaction between the amino acid asparagine and the sugars fructose and glucose. It is typically associated with the browning of foods like french fries, crisps and the brown crust of baked bread. The high oil temperatures of deep-fat frying and oven-baking temperatures are conducive to acrylamide formation.
The European Food Safety Authority, the UN Food and Agriculture Organisation and the World Health Organisation have all debated the risk of acrylamide, according to the FSAI. However, no formal measures for maximum levels of acrylamide have been introduced as still more knowledge is needed.
"When we're finished our research," says Dr Gormley, "We'll compare it with others."
One of the most detailed risk assessments of acrylamide was carried out by the Joint FAO/WHO Expert Committee on Food Additives and Contaminants in February. It concluded that people who eat large amounts of certain fried, roasted or baked foods may have an increased risk of cancer.
The FSAI recommends Irish people avoid acrylamide-rich foods but stress that people maintain a balanced diet. "It's not a black and white issue," says Dr Gormley, "The jury's still out on the danger of acrylamide."