“BACON BITS”/A cancer explainer
“On Monday the WHO classified high consumption of processed meats like bacon and sausage as a class one risk factor for colorectal cancer. But contrary to headlines, it’s NOT the same as smoking. Brooke talks with Ivan Oransky, who explains what the announcement actually means and how we should interpret it. Also, we revisit our Breaking News Consumer’s Handbook: Health News Edition with Gary Schwitzer to help you navigate the perennially murky world of health and diet reporting.”
This ~15 minute podcast breaks down how this story is being reported in a really disingenuous way, and also provides a useful series of steps to go through when you hear this kind of reporting, so that you can de-bunk the claims for yourself.
To expand on this, I wrote an explainer of the biology involved; this might also help you ignore the studies you don’t need to be stressing about:
tl;dr: Red meat isn’t going to “give you cancer”; if you get cancer, the vast majority of the time it won’t be linkable to a specific thing and is MOST likely just due to random chance. We like the illusion of control, but it’s probably just making us unnecessarily stressed.
I’m sure that the results of the red meat study are real. I just don’t think that there is a lesson here for the vast majority of the people reading and sharing the viral articles about it. There are lots of good reasons to eat less meat, but this shouldn’t be high on the list. Here is why -
Cancer is caused by the disruption to the regulation of cell growth and proliferation, an unavoidable consequence of basic principles of biology that also allow us to develop from single fertilized eggs into full humans. Cell growth and proliferation is caused by genes being turned on and off, leading to more cell-building proteins being made or activated, and then binding to cellular building blocks and “building more cell”.
In healthy bodies, it is common for cells to be cued to proliferate at the wrong times or to grow into the wrong cell types (i.e. becoming pre-cancerous). However, these cells often die, or the immune system is able to destroy them — this is probably happening right now, as you read this, and has probably always happened in all multicellular organisms. Cancer develops when the immune system can’t clear all the pre-cancerous cells, either because the immune system is weak and/or unable to detect the cancerous cells, or because cancerous cells are developing too quickly. The second scenario is the most common, happens by random chance, and none of us can do much to impact this either way.
I think about this as a consequence of being alive and having all the benefits of the amazing, complex, dynamic processes that occur in our bodies: In order to find the boundaries of just the right amount of dynamically alive, sometimes our bodies go a little too far. And sometimes we can’t pull back.
There are factors that can tip the scales of chance either way — from which genetic alleles you have (like the well-studied BRCA1 alleles that raise breast cancer risk) to exposure to carcinogenic stimuli (like blasts of the wavelengths of radiation from atomic bombs).
For example, skin cancer is caused by wavelengths of radiation (such as sunlight) that can penetrate the skin, and break DNA — when the cell repairs itself, it sometimes accidentally introduces mutations.
Other wavelengths of radiation can lead to hydrogens being knocked off water molecules, releasing oxygen— these are “free radicals” and they can do things like damage that cell’s DNA if the cell doesn’t clear them out using anti-oxidant molecules like vitamin D. However, to address a common myth, the radiation from cell phones is NOT at a wavelength that can do either of these things. Only very, very short wavelengths can interact with molecules.
Now, where does red meat fit in here? Epidemiologists look for the causes of cancer in two ways: (1) by investigating populations of people with high rates of cancer, to see if they all have something in common, or (2) by investigating a specific factor to see if people who are highly exposed have different rates of cancer.
When carcinogenic factors are identified by these kinds of studies, it’s rarely clear what the molecular mechanism is, and the results are also really dependent on population. For example, this meat study doesn’t tell us what specific thing in processed meat is doing what specific thing to the body to cause cancer, which means that this might still be a correlation and not a causation. In addition, and very importantly, the study is specific to people who are already at risk of colorectal cancer.
Cancer holds this sort of existential terror in our society. There are some very legitimate reasons for this special attention (like most people, I’ve had family members pass away from cancer; these diseases are still often deadly and are always unpleasant). However, looking at how information about cancer is communicated, I also see cancer fears as an expression of American society’s unhealthy obsession with individual safety.
It’s tantalizing to believe that we can explain and prevent every negative experience. That if we just read all the studies and designed our lives, we could control the outcomes of our choices and exist in perfect safety. But this is most certainly an illusion — and luckily so. The sooner we all recognize that, the sooner we will have the room to live without these false and anxious responsibilities, and the sooner we will stop blaming and shaming people who need support to overcome random and unforeseen disease.
Caveat: I’m not a cancer researcher or a doctor, so this is probably missing a lot of nuances, but these are the general principles as I understand them from a molecular biology background.
