Carcinogenicity of Food Mutagens and Risk Assessment
A series of heterocyclic amines were isolated from pyrolysates of amino acids and proteins and were shown to be highly mutagenic. This chapter summarizes available data on the carcinogenicities of these heterocyclic amines. Nine heterocyclic amines, namely, Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2, MeAaC, AaC, IQ, MeIQ, and MeIQx, have so far been shown to be carcinogenic. Liver tumors, identified histologically as hepatocellular carcinomas and hepatocellular adenomas, developed in all groups treated with heterocyclic amines. The carcinogenic risk of heterocyclic amines to humans must be evaluated. All the heterocyclic amines found in cooked foods and cigarette smoke condensate have been shown to be carcinogenic to mice and rats. This chapter discusses the dose-response relationship of the carcinogenicity of MeIQx in mice. When groups of 36 female CDF1 mice were given 0.06, 0.O2, 0.006, or 0.002% MeIQx in the diet for 83 weeks, their incidences of liver tumors were 82, 3, 0, and 0%, respectively.