Avoid Charred Meat,
Chemicals formed during cooking found in human milk
Breast-feeding mothers who consume charred meats
are probably passing dangerous environmental contaminants
on to their children, according to a first-ever study by
U of G researchers.
Heterocyclic amines - the mutagenic and carcinogenic products
formed during frying, broiling and grilling of meats - were
found in human milk during tests conducted by Prof. David
Josephy and post-doc researcher Lillian DeBruin of the Department
of Chemistry and Biochemistry and Perry Martos of Laboratory
"There have been a number of studies that have found
a link between consuming charred meats and an increased
risk of breast cancer," Josephy says. One investigation
concluded that women who ate red meat that was "very
well done" had a 4.6-fold increased risk of breast
cancer compared with those who usually ate meat that was
"rare" or "medium."
"But this is the first time analysis of these compounds
has been conducted on human milk," Josephy says. "We
can say with some certainty that most of these environmental
chemicals are also being absorbed by nursing infants, and
as a rule, infants are more susceptible than adults."
The research is reported in the journal Chemical Research
in Toxicology, publishedby the American Chemical Society,
the word's largest scientific society. The pilot study included
samples from 11 lactating mothers living near Guelph, 10
of whom are meat eaters. The environmental chemicals that
result from eating grilled meats were detected in nine of
the 11 samples, with one of the two exceptions being the
milk of the vegetarian donor.
"The presence of these environmental chemicals in
human milk means this is possibly a human mammary carcinogen,"
Josephy adds that animal meat is the most likely source.
"The chemicals are formed by heating creatine with
amino acids, and creatine is found almost exclusively in
muscle." This includes red meat, fish and chicken.
"Reducing the intake of overly cooked meats might minimize
exposure to these compounds," he says.
The chemicals have a relatively short lifespan in the body
- between eight and 24 hours - so cutting back on consumption
even just while breast-feeding might have a positive effect,
Although the study was a pilot project intended to test
the methodology of analysing milk samples for these contaminants,
Josephy says the findings are provocative. "We will
now embark on a more comprehensive study."
That work will include more detailed analysis of women's
dietary habits and is being funded by the Canadian Breast