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Multiple Chemical Sensitivity: Answering Criticism

We recently received pushback against our article on multiple chemical sensitivity. This is our answer.

Last September, we published an article I wrote on multiple chemical sensitivity (MCS), specifically on a French-language report commissioned by the Government of Quebec to understand the state of our knowledge on this condition. We recently received a number of emails critical of the article from people who have MCS and were unhappy with the conclusion of the report: that MCS seemed to be caused by chronic anxiety and not by exposure to minute amounts of chemicals in the environment. I encourage anyone interested in this story to go read the original article.

I answered the emails we received, and we thought it would be beneficial to a larger public for us to publish my answer below.

I come at this and other poorly understood conditions (like long COVID, on which I have also written) from the perspective of a scientist. Our own anecdotal experiences—persuasive and impossible to ignore—can lead us astray. To take a classic example, if I have the flu and my symptoms get worse, I can reach for a sugar pill, and my symptoms will start to recede. I could then use my personal experience to conclude that taking a sugar pill helps fight off the flu. But what really happened was that, independent of the sugar pill, my immune system kicked in. The flu is a self-limiting illness, but my own experience and how I interpret it can lead me down the wrong path.

The biomedical sciences are about removing these biases and bad interpretations that we are all subject to and trying to zero in on what is actually going on. That is why, for example, we do double-blinded randomized controlled clinical trials. It is an attempt, flawed though it is in practice, to remove non-specific variables and figure out if, for instance, a treatment really works. Science, when done properly, generates knowledge that can often be counterintuitive.

I feel for you and the symptoms you have. I am no stranger to chronic illness myself. Though you may not have felt it was enough, my article on MCS was woven through and through with compassion. I wrote, “When a patient consults a doctor about non-specific symptoms and a battery of tests reveals nothing, it can be irritating.” I wrote, “It’s worth highlighting the fact that people who suffer from an anxiety disorder are not ‘crazy.’” I also wrote, “This is not a problem that can be ignored.” I am on the side of the patients here, but I cannot rely on anecdotes to figure out what is really going on.

I was accused of basing my article on “a single study.” I did not. The report it was based on is 840 pages long. It was commissioned by the Province of Quebec’s own Ministry of Health and Social Services specifically because it recognized MCS as a problem and wanted to know how best to address it. The report was put together by Quebec’s own institute of health and looked at the entire body of scientific literature on MCS, not a single study. They analyzed over 4,000 papers and documents. This was a colossal effort. I have actually gone through the report many times. The attention to detail is astounding. When reading it, you cannot ignore the amount of care and dedication that was given to studying this issue. It is clear as day.

The authors of the report were accused of “ethical violations” (which is a ludicrous accusation in this context) by the Environmental Health Association of Quebec. I had a look at their website. To say that its sponsors are pushing for dubious products and claims is to put it mildly. One of them is a naturopath. Naturopathy is not science-based. It begins with the assumption that natural things are good for us, discounting the fact that natural ingredients like asbestos and snake venom are harmful to us. Poisons are defined by doses, not by whether or not something is natural or synthetic. Yet naturopaths are all too happy to provide unscientific diagnoses to people with real symptoms who feel let down by modern medicine.

One person pushing back against my article claimed that a course of antibiotics had “disabled the two toxin-removing chromosomes” they had. As someone who has studied both human genetics and molecular biology, I can 100% say that this is a bogus claim. I am not accusing the person making it of lying. Rather, this person has been fed a lot of nonsense from, I suspect, a naturopath. We do not have “toxin-removing chromosomes;” our chromosomes carry a wide variety of genes (and a lot of DNA whose function is still unknown). Genes that code for proteins involved in the removal of metabolic by-products, for example, are spread all over the genome. Chromosomes don’t specialize in certain functions.

To summarize: the report by the INSPQ represents a colossal undertaking and is, to the best of my understanding, a great summary of the state of our knowledge on MCS based on scientific studies, not anecdotes and intuitions. I understand your disappointment and the harm that bad experiences in the healthcare system have caused you, but this is no reason to latch onto unscientific explanations and to antagonize potential allies. I really wish the symptoms you experience would resolve themselves. Suffering is horrible. But we won’t get there by ignoring science.

N.B.: I have been asked many times if the 840-page report will ever be translated into English. I strongly suspect that it will not. However, a summary of the report is indeed available in English, first as a webpage here, and also as a four-page summary here.


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