Cancer & Over-Cooked Meat

Date: Tue, Nov 17, 1998

AP Science Writer
WASHINGTON (AP) -- Women who eat beef and bacon cooked until very well
done have a four times greater risk of developing breast cancer than those
who eat rare or medium meat, a study says.
Yet experts said Tuesday there is still too much uncertainty to
recommend changes in cooking habits.
Undercooked meat can pose a proven and well-known health risk, they
"We have found a link between well-done meat and breast cancer, but we
are still not sure of the cause," said Dr. Wei Zheng of the University of
South Carolina. "This is just one study. It is too early to jump to a final
Other researchers said Zheng's study, to be published Wednesday in the
Journal of the National Cancer Institute, "is intriguing," but not
conclusive. They said more research is needed.
"No single study should be the basis for changing public policy," said
Kathleen M. Egan, an epidemiologist at Harvard University and at Brigham
and Women's Hospital.
The links between diet and cancer are a hot subject of medical research,
but many scientists believe there are few definitive answers yet. They
recommend fruits and vegetables and avoiding obesity but generally say no
diet has been proven to prevent breast cancer.
Cooking meat at a high temperature, either by frying or grilling, has
long been known to cause the production of a chemical compound called
heterocyclic amines -- previously shown to cause cancer, Zheng noted.
"Charred meat has a high level of these compounds," he said. That is
also true of fish and chicken cooked at high temperatures, although the
study did not examine those.
Zheng and colleagues based their findings on the meat-eating habits of
273 women with breast cancer compared to 657 women without cancer.
To determine their meat-eating habits, the women were shown color photos
of hamburger, bacon and beefsteak cooked to various levels of doneness. The
women then picked out the meat picture that most closely matched their
routine meat preparation and consumption habits.
Many women had different preferences, depending on the type of meat. To
analyze that, Zheng said he created what he called a "doneness score."
Women who ate all three types of meat cooked either rare or medium were
given a score of 3. Those who preferred all three meats cooked very well
done were given scores of 9. When the preferences varied, there were scores
in between the two extremes. The vast majority preferred bacon well done or
very well done, while rare or medium was the most popular choice for steak
and hamburger.
Among women who preferred all meat very well done, with a doneness
scores of 9, there was a 462 percent greater chance of having breast cancer
when compared with women who ate rare or medium meat.
For very well done hamburger and bacon, the risks were 50 to 70 percent
greater. The risks were 220 percent greater for very well done beefsteak,
Zheng said.
The study was adjusted for other factors linked to breast cancer, such
as obesity, family history and whether the woman had undergone hormone
replacement therapy.
Dr. Christine Ambrosone of the National Center for Toxicological
Research in Jefferson, Ark., said Zheng's findings "are consistent with
what we have found in the laboratory."
Lab studies have linked cancer with some chemicals created when meat is
cooked at high temperatures, she said. Some studies, using nursing mice,
have shown that heterocyclic amines are present in breast milk. But she
cautioned against applying this laboratory data to humans.
"It is too early" to draw conclusions, Egan said. "The public needs to
stay tuned."
Right now, people should be more concerned about health risks from
undercooked meats, Egan and Zheng both said. There have been a number of
recent incidents of bacteria infection caused by eating undercooked
Zheng's solution: Boiling, steaming or baking meat until it is
thoroughly cooked, but not charred or overly done.
"Moderate cooking would be OK," he said.