Detection of PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) in themilk of healthy women

An increased risk of breast cancer has been observed in women who consume " very well-done" meats. Heterocyclic amines are mutagenic and carcinogenic p yrolysis products formed during high temperature cooking of meats. In the p resent study, human milk samples were analyzed for PhIP, one of the most ab undant dietary heterocyclic amine. A protocol was developed with a mixed-mo de cation exchange sorbent for the extraction of heterocyclic amines from m ilk. Milk samples were acquired from healthy Canadian women. With LC/MS ana lysis and the method of isotope dilution for quantification, levels of PhIP were determined in human milk samples. PhIP was detected in 9 of the 11 mi lk samples, at levels as high as 59 pg/mL (ppt). No PhIP was detected in th e milk of the vegetarian donor. Detection of PhIP in milk indicates that du ctal mammary epithelial cells are directly exposed to this carcinogen, sugg esting that heterocyclic amines are possible human mammary carcinogens.