International experts have called for urgent research to examine whether staple foods like bread, chips and crisps cause cancer.

The scientists were speaking at the end of a three-day emergency summit organised by the United Nations and World Health Organisation to examine claims that some food items include cancer-causing substances.

It followed a study in Sweden which found high quantities of acrylamide in a wide variety of food. That finding was backed up by similar research in the UK and Norway.

We need to do research quite urgently

Dieter Arnold, summit chairman

Acrylamide is known to cause cancer in animals and there are concerns that it could have the same effect in humans.

At the end of the summit, which was closed to the public and the media, the scientists said it was still too soon to draw firm conclusions on the issue or to make recommendations on eating habits.

Further research

The scientists called for an international network of laboratories to be set up to pool information from governments, regulatory authorities and industry on the possible risks.

They also urged food manufacturers to carry out studies.

Dieter Arnold, of the German Federal Institute for Health Protection of Consumers who chaired the meeting, said: "On the information we have at the moment, we cannot give consumers very specific advice such as to avoid eating chips of this or that brand."

But he added: "We need to do research quite urgently in order to be able to reduce the levels (of acrylamide) in food."

Jorgen Schlundt, the UN's food safety programme coordinator, said: "We know we get a lot of cancers from food, some of it might come, or it is very likely that it does come, from acrylamide.

"If we can modify the ways we produce food, so that we get less acrylamide, we will have less cases of cancer."

Food scare

Researchers from Stockholm University and Sweden's National Food Administration found acrylamide was formed when carbohydrate-rich foods such as potatoes, rice or cereals were heated.

The study said that an ordinary bag of crisps may contain up to 500 times more of the substance than the top level allowed in drinking water by the WHO.

It also showed that the chemical is found in high carbohydrate foods like bread and potato products which are common in many people's diets.

Tests on rats in Sweden showed that when deep fried potato and starchy foods cooked at high temperatures were fed to the animals, many of them developed cancer.

Acrylamide induces gene mutations and has been found in animal tests to cause benign and malignant stomach tumours.

It is also known to cause damage to the central and peripheral nervous system.

So far there is no proof that the foods would have the same harmful effects on humans.