Heating of food increases the duration of foods and make the food safer by reducing the level of microorganisms. On the other hand, heat treatment of food for a prolonged time and at high temperature can produce unwanted and harmful substances in the foods. Some of these substances are well studied, such as acrylamide and heteocyklic amines. Other substances, such as the substituted furans (SF) are much less studied. SF is produced during heating of food with high level of carbohydrates, and these SF's can be converted to potentially harmful substances in the human body by certain enzymes. Humans express these activating enzymes in many tissues in contrary to mice, which express the enzymes mainly in the liver. Therefore, humans might be more sensitive to the negative health effects of SF. We use "humanised" mice with human enzymes in several tissues to investigate whether SF can increase DNA damage and induce cancer. Our results shows that some of the SF's , such as furfuryl alcohol, can can react with DNA both in celle cultures and in experimental animals. Another SF, 2,5-dimethylfuran (DMF), was given to the "humanised" mice and the cancer development in the intestine was studied. The results show that it is not convincing evidence that DMF affect the cancer development in the intestine of mice. It remains to be studied whether the DNA reactive substance furfuryl alcohol can increase cancer development in mice. I addition we have measured the concentration of several SF's in foods in Norway and the level of metabolites from SF in the urine from humans. These measurements will be used to estimate the intake levels of SF's from foods in humans.
Colorectal cancer is among the most prevalent types of cancers in Norway and current data show that the risk of developing colorectal cancer is diet associated. Most foods are processed before consumed, and this leads to formation of new compounds some of which can be hazardous to humans. The substituted furans are a novel class of such food processing contaminants; some have already been shown to induce tumours in mice. However, little or no information on the hazard, human intake and occurrence in food are available for most members of this broad group of food processing contaminants. The project will give more relevant characterisation of the hazards from substituted furans. Humans do more efficiently bioactivate substituted furans than rodents, it is thereby imperative to use appropriate models. In our study in vitro and in vivo models with bioactivating systems more similar to humans will be used. Human intake studies along with analyses of substituted furan concentrations in food and their biomarker s in human urine, will together with the hazard characterisation give information to an evaluation of the human health risk. The results will be useful for scientists, authorities and industry.
The aim of this project is to evaluate the human health ris k of dietary exposure to substituted furans.