Panic: ‘Eating red meat significantly increases a post-menopausal woman’s chance of breast cancer’ according to BBC News reporting on a study from Leeds University. The researchers monitored 33,725 women over the course of seven years. Post-menopausal women who ate one 50g (two ounce) portion of red meat per day were 56 per cent more likely to develop breast cancer than those who did not eat red meat. The risk was 64 per cent for those who ate the most processed meat.
Lead researcher Professor Janet Cade said: ‘My advice to women who are consuming relatively high amounts of red and processed meat on a daily basis is to consider reducing their intake.’
Don’t panic: The findings in this study sound alarming but they are not that easy to interpret.
For example, 56 per cent more women in the ‘high consumption’ category for red meat developed breast cancer than in the ‘no meat’ category, the results for the ‘low’ and ‘medium’ consumption categories were actually higher (63 per cent and 64 per cent respectively). That difference is unlikely to be significant - and the same lack of signficance also applies to processed meat, where the difference between different levels of consumption was also small. Only where vegetarians were compared with meat eaters was there a statistically significant difference.
We also need to be sceptical about whether ‘red meat’ or ‘processed meat’ are biologically relevant categories at all. Pork, lamb and beef may have numerous biochemical differences, particularly when they can be cooked in a wide variety of ways. And it should be noted that the overall study population were a bit unusual to start with, being relatively health conscious (low levels of smoking and drinking, relatively high levels of nutrient supplement use). Furthermore, the vegetarians tended to be younger and even more health conscious than those who ate the most red meat. These factors could have affected the outcome.
The absolute risk of breast cancer was low in all the groups. For example, there were 106 cases of breast cancer in the ‘high red meat’ group out of 4,464 subjects ie, 2.4 per cent. In the ‘no meat’ group, the risk of breast cancer was 1.6 per cent. Is that the kind of difference in risk that would make someone quit eating steaks, burgers and sausages? Hardly.
As the authors of the present study note, other studies have indicated much smaller levels of risk - or no risk at all. So, the evidence against red meat is contradictory and even if it is real, the risk may not amount to very much in practical terms. No need to cancel those BBQs just yet.
Red meat ‘ups breast cancer risk’, BBC News, 3 April 2007
Meat consumption and risk of breast cancer in the UK Women’s Cohort Study, British Journal of Cancer, April 2007permalink