Californians are up in arms that the state hasn’t yet required labels warning of the dangers of hot dogs. The anger follows the International Agency for Research on Cancer (IARC) classifying processed meat as a definite, and red meat as a probable carcinogen. We take several issues with the science behind these decisions.
Studies examining carcinogenicity of foodstuffs rely heavily on self-reporting, which almost always yields questionable results. Anyone who’s reached into their chip bag to find it suddenly empty know how easy it is to underestimate consumption. And often, serving sizes are unclear. Do you have any idea how many ounces of ground beef were in the pasta you ordered last week?
We’re also limited by what we ask. Questionnaires which fail to control for every variable in life (which would be impossible) leave scientists with bad data.
Additionally, IARC’s ranking system doesn’t work as you’d think.
Rather than categorizing increasing risk, items are grouped based on the amount of research linking the substance to cancer. If many sources indicate a weak link, it is assigned to Group 1 (the “definites”). Conversely, if lack of interest in a subject yields only a single study exploring the cancer-causing potential of a substance which turns out to be dangerously carcinogenic, it will still be given a lower rank.
This evaluation of hazard (can something cause cancer) rather than risk (does something cause cancer) yields questionable results, so that motor oil is assigned the same category – Group 1 – as the ionizing radiation of a nuclear blast. Common sense will tell you that changing the oil in your car doesn’t carry the same consequence as walking into the smoldering remains of Chernobyl. Yet the two, and, apparently, processed meat, are Group 1 carcinogens.