Dissertation Defence: Inheriting the Toxic Effects of Our Ancestors Diet: Pre-Natal Glyphosate Exposure Induces Colonic Inflammation, Immune Metabolic Dysfunction and Behavioural Deficits in Mice

Jacqueline Barnett, supervised by Dr. Deanna Gibson, will defend their dissertation titled “Inheriting the Toxic Effects of Our Ancestors Diet: Pre-Natal Glyphosate Exposure Induces Colonic Inflammation, Immune Metabolic Dysfunction and Behavioural Deficits in Mice” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biochemistry & Molecular Biology.

An abstract for Jacqueline Barnett’s dissertation is included below.

Examinations are open to all members of the campus community as well as the general public. Registration is not required for in person defences.

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ABSTRACT

Glyphosate, commonly known as Roundup®, is heavily used in Canada, with over 25
million kilograms purchased annually. It is frequently applied pre-harvest, leading to high residues
in many foods consumed within Canada, including wheat, cereals, legumes, and soy. Glyphosate
can inhibit bacterial growth and promote bacterial dysbiosis, which is known to be causative in
inflammatory bowel disease (IBD). Canada has the highest incidence of new cases of IBD in the
world. This research aimed to determine if there are harmful effects on the gut bacteriome,
resulting in colitis associated with altered metabolic health and behavioral changes resulting from
prenatal glyphosate exposure.

Two physiologically relevant doses of glyphosate were chosen for the study: the
acceptable daily intake currently set by the Environmental Protection Agency (EPA) (1.75mg/kg
body weight/day) and the Average American dose calculated with a registered dietician based on
literature values of glyphosate within items that make up a typical North American diet (0.01mg/kg
body weight/day). Breeding pairs of colitis-resistant and colitis-susceptible mice were exposed to
glyphosate during pregnancy, and two generations of animals were raised.

The study found that healthy mice whose ancestors were exposed to glyphosate at both
doses developed colitis, metabolic dysfunction, and behavioral deficits, including impaired
memory and decreased locomotor activity. These effects persist two generations after exposure.
Similarly, colitis-susceptible offspring of animals exposed to glyphosate display increased
inflammation, impaired immune function, and alterations in critical metabolites implicated in the
gut-brain-microbiome axis, including neurotransmitter levels and microbial community structures.

This study highlights the profound and enduring impact of glyphosate exposure, even at
levels previously considered safe, on the gut bacteriome, metabolic health, and behavior through
multiple generations. Remarkably, healthy mice suffered more adverse effects than genetically
susceptible mice, suggesting that glyphosate-induced detrimental effects may be an
environmental factor contributing to the increased prevalence of IBD. The observed effects
underscore the need for a comprehensive understanding of the potential risks of widespread
glyphosate use, urging further exploration and consideration in public health and regulatory
practices