Monday, August 29, 2016

I Expose My Family to Carcinogens Everyday And So Do You

Last year, the International Agency for Research on Cancer (IARC) classified glyphosate, a common herbicide, as a probable carcinogen. I've been asked how it is that I can ingest "a known carcinogen",
"The Globally Harmonized System sign for carcinogens,
 mutagens, teratogens, respiratory sensitizers
and substances which have target organ toxicity." Wikipedia
so I'm going to take the time to outline what the IARC does, the difference between the IARC's ranking and risk, and why I expose myself and my child to known carcinogens everyday (a shout out to @mommyphd for editing this post).

First, it's important to note that the IARC's categorization of glyphosate contradicts statements from many other organizations including the European Food and Safety Authority. Second, the IARC's ranking has been controversial due to potential conflicts of interest. Third, to explore the data behind the IARC’s categorization, I highly recommend this blog post by Dr. Andrew Kniss. For the sake of simplicity, I'm writing this piece assuming that the IARC's ranking is correct and ethical.

What is the IARC?

The IARC is an agency of the World Health Organization and it reviews data regarding a substance's carcinogenicity to identify hazards. Their job is to answer these questions: Is there any evidence that substance X causes cancer? How much evidence is there? Based on the strength of data, not the likelihood of harm (the actual risk), it categorizes substances as "probably not a carcinogen", "not classifiable", "possibly a carcinogen", "probably a carcinogen", and "a known carcinogen". The IARC has only ever classified one substance as "probably not a carcinogen". If you’re not sure about the difference between hazard and risk, here’s an extreme example: is a meteor striking me a hazard? Yes… It is. I’d probably die or get injured if it struck me. Is it a risk? No. Apparently, there’s only a 1 in 1,600,000 chance that I’d get hit by a meteor in my lifetime and die.

That is the extent of the IARC's role: to determine the level of evidence for whether a substance has the potential to cause cancer. It doesn't tell you the level of risk or what you can do about it. That's why the IARC's classification is so confusing: it lumps processed meat in the same category as smoking. But does that mean that your risk of getting cancer from smoking two packs a day is the same as your risk of getting cancer by eating a pastrami sandwich? No, it doesn't. Does it tell you if your risk is the same if you smoke a cigarette once in your lifetime or if you eat 3 pastrami sandwiches a day? No, it doesn't. For that, we need to assess the risk of the substance and that is often done by public health organizations.

The Carcinogens We Encounter Every Day
Whether you're aware of it or not, every day you're choosing to expose yourself to at least one known carcinogen. That's because UV rays from sunlight are carcinogens. One of my son's favorite lunches is a sliced ham sandwich. And that's a carcinogen. There are many other possible and probable carcinogens that we knowingly expose ourselves to: my husband and I have cell phones, we eat red meat and french fries (the latter have acrylamide), and some of our lotions have aloe vera extract. Even hot beverages that we drink were recently classified as “probably a carcinogen”.

But thanks to public health officials that have assessed the risk and provided guidelines on mitigating risks in my life, my kid uses sunscreen when he's out in the sun and we try to stay in the shade. We don't eat red meat every day, and there are no public health guidelines on avoiding aloe vera extract because the evidence for actual risk of carcinogenicity is weak.

What About Glyphosate? What Should I do?

In the case of glyphosate, the World Health Organization has stated that the amount of glyphosate residues found in our food is unlikely to be carcinogenic. In other words, the risk to my family is negligible. The risk to pesticide appliers may be higher and worker safety organizations may provide recommendations specific to pesticide application for such individuals to mitigate their risks.

So many things around us are potential hazards and could possibly kill us some way or another. However, it’s more important to understand the level of risk that something poses in making decisions about how to keep ourselves and our families safe. It’s also important to note that we cannot avoid hazards: even something as simple as eating a salad, be it organic or conventional, has the risk of a foodborne illness. What’s important is that we make informed decisions based on genuine risk, otherwise we live our lives unnecessarily fearing our environment and our food. We could live cooped up inside our houses, in a "chemical-free" bubble with UV-reducing windows or shut-out curtains, but that's not what our public health officials recommend. Following their recommendations ensures that we reduce the risk for the things that can harm us by using sunscreen, eating plenty of properly washed fruits and veggies, getting our vaccinations on schedule, using seat belts and having car seats installed properly, etc. We should focus our efforts on following guidelines put forth by our public health officials and medical institutions, rather than creating boogie-men out of low-risk items in our environment.


  1. Please, fix the font for the last paragraph. The sudden change in serif hurts my eyes :)

  2. Thumbs up - but could you change meteorite to meteor? Unless you're envisioning somebody picking up a chunk of rock from a quarry and hurling it at somebody.