Glyphosate, Gut Bugs and Autism

A controversy I have been following:  what do we REALLY know about glyphosate (the chemical found in the herbicide, Roundup) and its effects on health.  As you all know, I like to look at the actual science, not the sensationalist media headlines.  Back last October, I wrote about a 2019 article assessing this very question, and if you remember, it concludes that we simply do not as yet know enough to well, conclude anything.  It does, however, look like the chemical does affect the microbiome in a negative way and this is an area ripe for continued research.

As I was combing through a desktop file of articles I’ve contemplated writing about, I spotted one on the relationship between glyphosate, the microbiome and autism which is certainly worth a mention, even though it predates the previous article by a year.[i]  Why?  Because it specifically looked the how the ingestion of glyphosate can lead to higher levels of Clostridia in those who develop autism, and as you know from many of my previous posts, this is certainly one of the, if not THE, most suspect of bacteria in the etiology of this developmental disorder.  Clostridia is a huge producer of propionic acid as well as toxins.  Take a look at a few of my prior writings on this subject, maybe, before you proceed in reading this:  you may get a clearer idea of how all this fits together.

Scientists from around the world collaborated on this paper.  They culled the medical literature for papers on “Clostridium bacteria and the probability of developing and/or aggravating autism among children.”  They ended up using 9 papers which fit their research criteria, covering more than 495 people (310 with autism and 185 controls).  The papers confirm the dysbiosis present in those with autism, including a vast “…proliferation of intestinal Clostridia” which “…may contribute to the clinical picture of ASD, likely functioning as key elements in the etiology of autism.”

“Pathogenicity of several anaerobic bacteria and their virulence is based on secreted toxins, mainly produced by Clostridial species. Despite being non-invasive bacteria, these microbes can exert long-distance harmful effects (e.g., brain) if their secreted molecules pass through the intestinal barrier and disseminate by the general circulation to remote organs or tissues, where they are active. For instance, it is known that Clostridium difficile toxin B can trigger programmed cell death in granule neurons and changes in density and spine morphology.”  (I added the underlining.)

That is, metabolites excreted by this particular Clostridial species can distort neurons. Wait!  Why does that sound familiar?!  Oh…that’d be because I wrote about that very topic last Thursday, describing that new paper out of Korea in which researchers applied propionic acid to neurons and saw them develop abnormally with a lack of spines, which are crucial for normal transmission of signals.

As I say to you all the time:  at what point does something become simply accepted as scientific fact?  I have no idea the answer…

Now for the connections with glyphosate: simply put, it turns out that GLY, which is the active ingredient in Roundup (which is the most heavily used herbicide in the world – more than 300 million pounds are applied annually), affects gut bacteria.  However, pathogenic bacterial species like Clostridium perfringens and Clostridium botulinum are highly resistant to it, whereas beneficial species, like Lactobacillis, many of the Bifidobacterium family, many in the Enterococcus family, etc.) are moderately to highly susceptible.  This is not the first time such detrimental changes to the microbiota have been described – again, I refer you to the post I wrote on glyphosate last October.

Again, the connection of the altered gut flora found in autism to the ingestion of glyphosate and the development of autism is still considered hypothetical.  I am watching the science develop to see if at some point, the weight of evidence shifts this from theory to fact.

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[i] Argou-Cardozo, I, Zeidan-Chulia, F.  Clostridium Bacteria and autism spectrum conditions: a systematic review and  hypothetical contribution of environmental glyphosate levels.  Medical Sciences. 2018;6(29).  doi:10.3390/medsci6020029