other contributing factors
The research team (Norat et al) makes an interesting comment on
association between heme iron and cancer risk, which is thought to be able
to explain why red meat increases cancer risk while poultry does not.
however in my view, it is also possible that cattle breeding method and
condition also contribute to this increase. the grass where the cattle are
fed might be contaminated by pesticides, and the cattle might have been
injected a drug (either to improve the quality of meat or to cure the
disease) which might be carcinogenic.
i'd like to underscore another rapid response though, which questions
whether red meat itself really has something to do with higher risk of
cancer. i agree that it is the processing method which matters (especially
when nitrites or nitrates are added). but the problem is not merely the
meat itself; probably the loss of plant-based foods from our daily diet
would better describe it. these products, which are protective against
cancer, have been replaced by meat. and the drawback is:
a number of people, while eating more meat, tend to skip plant-based
foods so they consume less fibre (as the authors mention) and, i think,
less antioxidants as well. this means that less protective substances are
available in the body to prevent carcinogenesis, and the result is a
higher risk of cancer.
Competing interests: No competing interests