Canadian Researchers Find Cancer Suspect From Grilled Meat In Human Milk

Although no one is certain whether the chemical, called PhIP, actually causes cancer in humans, the researchers suggest that it may increase the risk of breast cancer in women as well as pose a cancer risk to nursing infants. Still, breast-feeding remains preferable to formula feeding, and there are ways to minimize PhIP exposure, they add.

The finding appears in the Nov. 19 print edition of Chemical Research in Toxicology, a peer-reviewed journal of the American Chemical Society, the world’s largest scientific society. It was published in the Web version of the journal on Oct. 16.

“Since exposure to [PhIP] is chiefly from dietary meats, reduction in the intake of cooked meats and avoidance of “very well-done” meats might minimize exposure to these compounds,” says P. David Josephy, a professor in the department of chemistry and biochemistry at the University of Guelph in Guelph, Ontario. “Very well-done” means charbroiled or grilled meats, considered the major dietary source of the chemical, he says.

Many toxic chemicals have been found in human breast milk, including PCBs, dioxin, nitrosamines, ethanol and nicotine. Few are strongly associated with breast cancer. PhIP is one of the few suspected mammary carcinogens found in breast milk that is almost exclusively associated with grilled meat, says Josephy. It is also the first member of its chemical class, a group of highly mutagenic compounds known as heterocyclic amines (HCAs), to be found in human breast milk, he says.

Milk samples were obtained from 11 healthy lactating volunteers, all residing in or near Guelph. Using chemical tests, the researchers detected trace levels of PhIP in nine of the samples at levels as high as 59 parts per trillion. All but one of the women tested had eaten grilled meat at least once during their last three meals, according to the researcher.

In the woman who did not eat meat, no PhIP was detected. Unexpectedly, no PhIP was found in the milk sample from one of the meat-eaters, says Josephy. Individual differences or differences in the type of meat and preparation of the meat may help explain this result, but these factors have not been fully analyzed, he says. Future studies are planned to evaluate these factors.