A higher intake of barbecued, smoked or grilled meat before
diagnosis was also associated with 23 percent higher odds of death
from all causes, the study found.
Of the three cooking options, smoking may be the worst. Routinely
eating smoked beef, lamb and pork was tied to a 17 percent greater
risk of death from all causes and 23 percent higher odds of dying
from breast cancer.
"There are many carcinogens found in grilled or smoked meats," said
lead study author Humberto Parada, a researcher at the University of
North Carolina at Chapel Hill. "One of the most common are
polycyclic aromatic hydrocarbons (PAH), which are formed during
combustion of organic material."
Women may be exposed to these carcinogens by cigarette smoke or air
pollution, which are associated with an increased risk of developing
breast cancer, Parada said by email. Some research has suggested
exposure to these chemicals through grilled or smoked meat can
increase the risk of breast cancer, but the current study offers
some of the first evidence suggesting it also influences survival
"Grilling or smoking meats produces PAHs much more readily than
other cooking methods, such as pan-frying," Parada said. "Several
factors may influence the formation of PAHs including ‘doneness’ and
meat type - higher fat content may result in the formation of more
For the current study, researchers interviewed 1,508 women diagnosed
with breast cancer about their eating habits in 1996 or 1997 and
then questioned them again five years later.
After following half of the women for at least 17.6 years, there
were 597 deaths including 237 fatalities from breast cancer.
Compared to women who consistently ate only small amounts of
grilled, barbecued or smoked meat, women who consumed a lot of these
foods both before and after their diagnosis were 31 percent more
likely to die during the study period, researchers report in the
Journal of the National Cancer Institute.
Women who included poultry and fish in their diet before or after
their breast cancer diagnosis were 45 percent less likely to die
during the study than women who didn't eat these foods.
Lower levels of saturated fats in chicken and fish relative to red
meats might help explain this, Dr. Pagona Lagiou, a researcher at
the University of Athens Medical School in Greece who wasn't
involved in the study, said by email.
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It's also possible that chicken and fish have a protective effect
because women eat less red meat, said Carrie Daniel-MacDougall, a
researcher at the University of Texas MD Anderson Cancer Center in
Houston who wasn't involved in the study.
"Simply increasing fish or poultry intake, without reducing red meat
intake, is likely to be less beneficial for cancer prevention,"
Daniel-MacDougall added by email.
One limitation of the study is that it relied on women to report how
often they consumed different foods and didn't assess portion sizes
or the number of times they ate meats each week, the authors note.
The study also isn't an experiment, so it cannot prove that
different types of meat influence survival odds with breast cancer.
Still, the findings suggest women should pay attention to how they
cook their food to minimize their exposure to carcinogenic
chemicals, said Dr. Mingyang Song, a researcher at Massachusetts
General Hospital in Boston and Harvard University who wasn't
involved in the study.
"These chemicals can be produced from wood smoke or when fat and
juices from meat grilled directly over an open fire drip onto the
fire, creating flames and smoke," Song said by email. "Generally,
the fattier the meat is, the higher the chemical levels will be."
SOURCE: http://bit.ly/2iATBNW Journal of the National Cancer
Institute, online January 4, 2017.
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