Today, after classifying coffee as a possible cause of cancer in 1991, the cancer research arm of the World Health Organization has absolved the drink. Sort of.
The International Agency for Research on Cancer (IARC) performed a detailed review of more than 1,000 studies on coffee and declared in the journal The Lancet Oncology that there is insufficient evidence to believe that it causes cancer.
The IARC classifies substances from group 1 (carcinogenic to humans) to group 4 (probably not carcinogenic). There is just one substance in group 4: an ingredient in nylon used in yoga pants and toothbrush bristles. So, yes, that means that despite the new investigation, coffee is only in group 3, “not classifiable as to its carcinogenicity to humans.”
If these confusing designations sound familiar, that’s because the IARC is the same body that incited bacon hysteria in the fall by saying that processed meats were group 1, definitely carcinogenic, and red meat was group 2A, probably carcinogenic. (Importantly, they look at the strength of the evidence that something causes cancer, not the relative risk of developing cancer from that substance, so bacon is still not as bad for you as, say, smoking.)
The coffee news marks the first time in a while they’ve downgraded something, so we’ll raise a mug to that. They even found lower risks of certain cancers among coffee drinkers but, of course, they were quick to say that it doesn’t prevent cancer — there’s just an association.
But, in its supreme buzzkillness, the IARC found that consuming drinks like tea and yerba mate above a scalding 149 degrees (65 degrees Celsius) was linked to esophageal cancer. Super-hot beverages are now group 2A, alongside red meat. Heads up, annoying Starbucks customers.