McGill Alert / Alerte de McGill

Updated: Thu, 07/18/2024 - 18:12

Gradual reopening continues on downtown campus. See Campus Public Safety website for details.

La réouverture graduelle du campus du centre-ville se poursuit. Complément d'information : Direction de la protection et de la prévention.

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How Chemicals Affect Us

A New York Times article featured the headline “How Chemicals Affect Us.” Even before reading a single word, I was pretty sure the columnist was not going to discuss how antibiotics cure infections, how preservatives protect us from eating moldy food or how detergents clean our clothes. I knew I’d be reading a litany of warnings about toxins, poisons and endocrine disruptors. Unfortunately, that’s what the term “chemical” has come to mean. To many, chemicals are the substances that insidiously invade our lives and shorten them.

A New York Times article featured the headline “How Chemicals Affect Us.”  Even before reading a single word, I was pretty sure the columnist was not going to discuss how antibiotics cure infections, how preservatives protect us from eating moldy food or how detergents clean our clothes.  I knew I’d be reading a litany of warnings about toxins, poisons and endocrine disruptors.  Unfortunately, that’s what the term “chemical” has come to mean.  To many, chemicals are the substances that insidiously invade our lives and shorten them.

The columnist was right about one thing.  Chemicals do affect us!  And they do so in every conceivable way!  Take away oxygen and you die.  Eat an improperly processed puffer fish, and the natural tetradotoxin it harbours will kill you.  If you have a headache, aspirin comes in handy.  Even when we talk about genetic effects, it comes down to a matter of chemicals.  Genes code for proteins, and they are of course chemicals.  So are the endocrine disruptors that garner so much publicity, and arouse so much fear.  My view is that the concern that endocrine disruptors generate is out of proportion to the existing evidence about their effects on humans.  We are surrounded by such compounds to be sure...both natural and synthetic.  But they are just a tiny fraction of all the chemicals to which we are exposed.  Millions and millions of chemicals!  One can take virtually any single compound, do animal studies, and find something.  But extrapolating to humans is a touchy business.

The problem is that the human body is very complex, and its interaction with the environment is virtually undecipherable.  We are exposed to too many compounds, and how they interact with each other and with the naturally occurring compounds in our body, defies analysis.  The bottom line is that nobody really "knows," because the effects of trace chemicals cannot be teased out from the biological noise.  There is also the implication that the endocrine disruptor problem can be solved by eliminating synthetic compounds such as bisphenol A or the phthalates.  These have received a lot of publicity but the fact is that we are awash in a plethora of endocrine disruptors, both natural and synthetic.  Is bisphenol A worse than soy?  Do we stop drinking milk because it contains estrogens?  Do we ban alfalfa sprouts?

I'm afraid that the people who target one class of substances are unaware of the chemical complexity of life.  Let me try an analogy.  Suppose you’re listening to a symphony orchestra and one string on a violin breaks.  Do you think anyone would notice a difference in the sound?  I highly doubt it.  Similarly, removing one compound from the millions to which we are exposed is unlikely to have a significant effect on life.  Unlikely, but I suppose, not impossible.  Basically, both sides of the endocrine disruptor debate imply that they know more than they actually know, or indeed, can be known.

I say, wear your seat belt, don't smoke, eat lots of fruits and vegetables, watch your caloric intake, vaccinate, don’t bake in the midday sun, and get plenty of exercise.  All these are known to affect us in a positive way.  The stress created by the worries of how "chemicals affect us" may do more damage than the chemicals themselves.  But of course that is just a guess.  Hopefully an educated one.  Eventually, we may have a better answer.  Biomonitoring has been going on for years and within a short time we will have enough retrospective data to come to some conclusion.  We will see whether people who had, let's say higher levels of BPA in their blood, have a different health outcome than those with lower levels.  It will still be hard to eliminate confounding factors, but at least we will have some human data to consider instead of all this conjecture based on animal studies and associations that do not prove cause and effect.

 


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