Neurotoxic effects of glyphosate
Numerous studies have demonstrated the neurotoxic effects of glyphosate and glyphosate-based herbicides in various species, including rats, mice, pigs and fish. The findings comprise alterations in nerve transmission, the destruction of nerve cells and behavioural disturbances. Glyphosate can get into the brain by crossing the so-called blood-brain barrier. Once in the brain, oxidative stress, neuroinflammation and deregulation of signalling pathways are the main mechanisms reported to cause the neurotoxic effects of glyphosate. In addition, several rodent studies identified behavioural effects of glyphosate in offspring after exposure during gestation and early postnatal development.
Remarkably, an industry study performed in 2001 that led U.S.EPA to set the so-called no-observed-adverse-effect level (NOAEL, used to calculate the acceptable risk for humans) was ignored by the European authorities (EFSA). In this study, after oral exposure of pregnant rats at 10, 25 or 100 mg/kg body weight, decreased motor activity was observed in offspring of the two highest dose groups on day 14 after birth. Thus, U.S. EPA concluded that NOAEL was at 10 mg/kg – the lowest NOAEL recognized by regulatory authorities in any of the toxicity studies on glyphosate.
Besides those results from animal experiments, epidemiological studies indicate an increased risk for neurobehavioral disturbances in children after maternal exposure to glyphosate, an association between glyphosate exposure and impaired visual memory, and a significant increase in the risk of developing Parkinson’s disease.
Resources
Articles :
The New Lede (2022) : New study says glyphosate may be linked to neurodegenerative diseases
Sparks (2019) : PARKINSON’S AS A MAN-MADE DISEASE, PART 2: THE PILE OF LITERATURE
Parkinson Vereniging (2023) : Glyfosaat. Neurotoxicity
Le Figaro (2022) : Colombie: euthanasie d'un ex-policier longtemps exposé au glyphosate
Le Monde (2022) : une étude industrielle sur la neurotoxicité de l’herbicide soustraite aux autorités européennes
Scientific research papers
Caballero, M. et al., “Estimated Residential Exposure to Agricultural Chemicals and Premature Mortality by Parkinson’s Disease in Washington State”, (Int. J. Environ. Res. Public Health, 2018).
Martinez, A. et al., “Effects of glyphosate and aminomethylphosphonic acid on an isogeneic model of the human blood-brain barrier”, (Toxicology Letters, 304, 2019).
Fuhrimann, S. et al., “Exposure to multiple pesticides and neurobehavioral outcomes among smallholder farmers in Uganda”, (Environment International, 152, 2021).
Yaoyu Pu et al., “Autism-like Behaviors in Male Juvenile Offspring after Maternal Glyphosate Exposure”, (Clin Psychopharmacol Neurosci 19(3), 2021).
Mie, A., Rudén, C., “What you don’t know can still hurt you - underreporting in EU pesticide regulation”, (Environ Health 21, 79 (2022)).
Costas-Ferreira, C, et al., “Toxic Effects of Glyphosate on the Nervous System: A Systematic Review”, (Int. J. Mol. Sci. 2022, 23, 4605).
Winston J K et al., “Glyphosate infiltrates the brain and increases pro-inflammatory cytokine TNFα: implications for neurodegenerative disorders” (Journal of neuroinflammation, 2022).
Ojiro, R. et al., “Comparison of the effect of glyphosate and glyphosate-based herbicide on hippocampal neurogenesis after developmental exposure in rats”, (Toxicology, 483, 2023).