Comment by tptacek
1 day ago
Ahhh, of course. Nobody in academia studying herbicide toxicity can get the funding to investigate whether one of the most famous and widely used modern herbicides has human health impacts. After all, there must only be a couple people in the world working on this, and not a couple people in every R1 and R2 research institution in the world, all of whom would become famous if they published a dispositive connection on this.
Unfortunately science just isn't as glamorous as you portray it. Many researchers at many institutions have demonstrated the toxicity in question but it turns out that this does not make you rich and famous. It is quite difficult to become famous by conducting scientific research carefully and responsibly (much to my chagrin). It is the popularizers who receive notoriety, and those are a mixed bag. Few scientists care to enter that field.
"The doses of glyphosate that produce these neurotoxic effects vary widely but are lower than the limits set by regulatory agencies. Although there are important discrepancies between the analyzed findings, it is unequivocal that exposure to glyphosate produces important alterations in the structure and function of the nervous system of humans, rodents, fish, and invertebrates."
Costas-Ferreira C, Durán R, Faro LRF. Toxic Effects of Glyphosate on the Nervous System: A Systematic Review. International Journal of Molecular Sciences. 2022; 23(9):4605. https://doi.org/10.3390/ijms23094605
"Today, a growing body of literature shows in vitro, in vivo, and epidemiological evidence for the toxicity of glyphosate across animal species."
Rachel Lacroix, Deborah M Kurrasch, Glyphosate toxicity: in vivo, in vitro, and epidemiological evidence, Toxicological Sciences, Volume 192, Issue 2, April 2023, Pages 131–140, https://doi.org/10.1093/toxsci/kfad018
"Utilizing shotgun metagenomic sequencing of fecal samples from C57BL/6 J mice, we show that glyphosate exposure at doses approximating the U.S. ADI significantly impacts gut microbiota composition. These gut microbial alterations were associated with effects on gut homeostasis characterized by increased proinflammatory CD4+IL17A+ T cells and Lipocalin-2, a known marker of intestinal inflammation."
Peter C. Lehman, Nicole Cady, Sudeep Ghimire, Shailesh K. Shahi, Rachel L. Shrode, Hans-Joachim Lehmler, Ashutosh K. Mangalam, Low-dose glyphosate exposure alters gut microbiota composition and modulates gut homeostasis, Environmental Toxicology and Pharmacology, Volume 100, 2023, 104149, ISSN 1382-6689, https://doi.org/10.1016/j.etap.2023.104149. (https://www.sciencedirect.com/science/article/pii/S138266892...)
I quickly checked the first study linked and it's a meta analysis.
It relies on studies in rodent that get exposed to amounts of glyphosate that are absurdly high. Equivalent human absorption would be in the gram range, to the point where someone eating 250g of bread everyday would have 1% of this mass ingested as glyphosate.
By this standard, things like vitamins and minerals are toxic as well.
It makes no sense, to me it looks like bad science.
You have not assessed the facts critically. The argument in favor of glyphosate's safety is that, as the herbicidal action is the result of disrupting an amino acid synthesis pathway that in animals does not exist, it is therefore harmless to animals. This argument is already fallacious: all it does is establish the mechanism by which it is harmful to plants. These studies evidence that glyphosate is harmful to animals and investigate the mechanisms underlying the harm. The fact that these experimental conditions are not the same conditions under which glyphosate is consumed in the food chain does not make it bad science, because science is concerned with knowledge that generalizes (e.g. biological mechanisms and pathways) and these mechanisms cannot be gleaned by reproducing the conditions already in place.
The comparison with vitamins is not relevant, and to bring it up suggests you are not thinking clearly.
I thought that from reading the first part of the first meta sample too, but in that same paragraph is mention of a second study that apparently did find relevant issues at low doses in vitro of human cells at environmentally relevant concentration levels.
In fact the purpose of meta analysis is to compare and contrast the conflicting research and results on a topic. It's very useful when forming a scientific view.