CANCER RISK OF HETEROCYCLIC AMINES IN COOKED FOODS - AN ANALYSIS AND IMPLICATIONS FOR RESEARCH

Heterocyclic amines (HAs) are formed as pyrolysis products during the cooking of meats/fish. These substances are potent mutagens in the Ame s/Salmonella assay and are also carcinogens in laboratory animals. In order to assess the magnitude of the cancer risk posed by their presen ce in the US diet, we estimated the average intakes of HAs, based on a nalyses of the concentrations of HAs in cooked foods and data from a d ietary survey of the US population and quantified the cancer potencies of the individual compounds using dose-response data from animal bioa ssays. Measured concentrations of HAs in cooked foods were taken from a major review of the open literature. Only those concentrations that were associated with normal cooking conditions were chosen for use in estimating dietary intakes. The average consumption of HA-bearing food s was determined by analyzing statistically the intakes of 3563 indivi duals who provided 3 day dietary records in a USDA sponsored random su rvey of the US population during 1989. Dietary intakes of the five pri ncipal HAs in descending order mere 2-amino-1-methyl-6-phenylimidazo [ 4,5-b]pyridine (PhIP) > 2-amino-9H-pyrido[2,3-b]indole (A alpha C) > 2 -amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) > 2-amino-3,4,8-t rimethylimidazo[4,5-f]quinoxaline (DiMeIQx) > 2-amino-3-methylimidazo[ 4,5-f]quinoline (IQ). The carcinogenic potencies, in contrast, were al most the reverse order: IQ > DiMeIQx > MeIQx > PhIP > A alpha C. An up per-bound estimate of the incremental cancer risk is 1.1 x 10(-4), usi ng cancer potencies based on a body surface area basis. Nearly half (4 6%) of the incremental risk was due to ingestion of PhIP. Consumption of meat and fish products contributed the most (similar to 80%) to tot al risk.