Processed Meats and Cancer
The World Health Organization (WHO)'s latest report has it classifying processed meats (salami, bacon, hams, hot dogs) as a Class I carcinogen, and red meats (beef, pork, and lamb) as a Class II A carcinogen. Higher levels of consumption were associated with increased risk of heart disease (72%) and cancer (11%) giving meat eaters a scare, and meat based industries an even bigger scare. The question is, how worried should we be?
What is red meat, and processed meat?
Red meat is any meat that is red prior to cooking: Beef, lamb, and also pork. Processed meat is meat that isn’t consumed right away. Salting, smoking, curing, are all forms of processing designed to make the meat last longer. Not included are fresh chicken, turkey, or fish.
What does carcinogen mean?
Carcinogen means, cancer causing in humans.
What does Class I Carcinogen mean?
Class I carcinogen means that there is enough scientific consensus that the substance in question is definitely cancer causing in humans.
What does Class II A carcinogen mean?
Class II A carcinogen means that there is enough scientific consensus that the substance in question is probably cancer causing in humans.
There is a common misunderstanding about how carcinogenicity is rated. Class I carcinogens include dreadfully scary compounds like arsenic, asbestos, and plutonium, but the rating doesn’t mean that processed meat is just as dangerous as arsenic. What this means is that it is known that processed meat is a factor in causing cancer; the evidence for this is as strong as it is for smoking increasing the risks of cancer. Carcinogenicity is a measurement of how much evidence there is that the compound is cancer causing; carcinogen classification is not a measurement of how dangerous, or how much it increases the risk of cancer.
The looming question is, just how risky is eating red meat? After all, driving kills over 30,000 people in the U.S. alone, but that does not stop people from driving. Clearly, we are individually, and as a society, willing to accept some risks, based on the benefits it provides. Processed and red meats increases the risk of colorectal cancers by 17-18%. The lifetime risk of this particular cancer is around 5% 1. If you accept my admittedly gorilla statistics in light of the various uncertainties here, the overall increase in total risk is somewhere around 1%. This is significantly less than the danger of excessive alcohol consumption or the dangers of smoking, in part, because the latter has a higher relative risk, and in part because of the higher absolute risk of the cancers that smoking and alcohol consumption contribute to.
Does this study not matter then? How worried should we be?
Overconsumption of meat, especially red meat, being linked to cancer has been cited numerously already. Very few people, meat-eaters or not, believe that eating meat in large quantities is great health advice. This study also mentions that the direct link is hard to isolate because heavy meat-eaters often make other poor lifestyle choices as well, which may be contributing to the cancer as well. If you are a heavy-meat eater, you should definitely think about cutting down.
Is the occasional steak dinner now a serious risk? No. The researchers report that far more significant lifestyle related risks are smoking, alcohol consumption, and obesity. What’s significant about these studies is that the evidence against red meat is compelling. Even a relatively small amount like 50g of processed meat makes a measurable risk difference. It is not stated whether this risk increases linearly as more meat is consumed. Either way, the relative risk of meat eating, however, is quite small compared to other known risk factors like alcohol or smoking, which cause very common cancers, and increase its risk significantly.
It’s up to each individual to determine how they choose their lifestyle in consideration of the risks, benefits, and the enjoyment they gain from what they do. For the most part, we already know that quinoa and blueberries are better than red meat, and take-out fast food. The greatest takeaway from this, and many similar studies is a confirmation of what we already know or at least suspect. A diet full of red and processed meat is probably unhealthy. Secondly, those who do eat red meat as a regular part of their diet should consider adding more fiber in their diet, exercising, and if possible, to cut down the amount of meat they consume. Is it a must avoid food? Probably not. For all practical purposes, what it does is confirm Paracelsus : Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy.