How Does Glyphosate Affect Brain Health and Increase Alzheimer’s Risk?
Arizona State University researchers discovered that even brief exposure to glyphosate, the active ingredient in common weed killers, causes persistent brain inflammation long after contact ends. The December 2024 study, published in the Journal of Neuroinflammation, revealed that exposure to this herbicide increases the risk of neurodegenerative disease and triggers Alzheimer’s-like effects in mice. These findings raise serious questions about current safety thresholds for a chemical that most Americans encounter daily.
5 Key Points
- Researchers found glyphosate crosses the blood-brain barrier and causes lasting neurological damage
- Even low-dose exposure within current “acceptable” limits produced harmful brain effects in mice
- Damage persisted after a six-month recovery period without exposure
- Farm workers and agricultural laborers face higher risk through inhalation and skin contact
- Most Americans have been exposed to glyphosate during their lifetime
What Did Researchers Discover About Glyphosate’s Impact on the Brain?
Ramon Velazquez and his ASU-Banner Neurodegenerative Disease Research Center research team demonstrated that glyphosate exposure results in significant brain inflammation. Their study, conducted in collaboration with the Translational Genomics Research Institute (TGen), tracked both the presence and impact of glyphosate’s byproducts in the brain long after exposure ended. The researchers observed neuroinflammation, Alzheimer’s-like symptoms, anxiety-like behaviors, and premature death in the test subjects.
“Our work contributes to the growing literature highlighting the brain’s vulnerability to glyphosate,” Velazquez said. “Given the increasing incidence of cognitive decline in the aging population, particularly in rural communities where exposure to glyphosate is more common due to large-scale farming, there is an urgent need for more basic research on the effects of this herbicide.”
Why Should People Be Concerned About Current Safety Guidelines?
The ASU researchers tested two levels of glyphosate exposure: a high dose similar to levels used in previous research and a lower dose approximating the current acceptable limit for humans. Alarmingly, even the lower dose led to harmful effects in the brains of mice, and these effects persisted after a six-month recovery period during which exposure was discontinued.
The U.S. Environmental Protection Agency currently sets tolerance limits on pesticide residues that can legally remain on food products. The EPA has maintained that glyphosate is minimally absorbed into the body and primarily excreted unchanged, making certain levels safe for human exposure.
“Herbicides are used heavily and ubiquitously around the world,” said co-author Patrick Pirrotte, an associate professor in TGen’s Early Detection and Prevention Division and director of the Integrated Mass Spectrometry Shared Resource at TGen and City of Hope. “These findings highlight that many chemicals we regularly encounter, previously considered safe, may pose potential health risks. However, further research is needed to fully assess the public health impact and identify safer alternatives.”
A visual representation of the ongoing legal battle concerning Roundup weed-killer products and their potential health risks.
Who Is Most At Risk From Glyphosate Exposure?
According to the Centers for Disease Research, farm laborers, landscape workers, and others employed in agriculture have a higher likelihood of glyphosate exposure through inhalation or skin contact. However, the study suggests that the general population may also face risks by ingesting glyphosate residues on foods treated with the herbicide.
“My hope is that our work drives further investigation into the effects of glyphosate exposure, which may lead to a reexamination of its long-term safety and perhaps spark discussion about other prevalent toxins in our environment that may affect the brain,” said Samantha Bartholomew, an ASU PhD candidate and first author on the paper.
The research team’s findings build upon earlier ASU studies that demonstrated a link between glyphosate exposure and heightened risk for neurodegenerative disorders. Previous research showed that glyphosate can cross the blood-brain barrier, a protective layer that typically shields the brain from harmful substances.
How Might These Findings Impact Future Regulations?
The study, funded by the National Institutes on Aging, the National Cancer Institute of the National Institutes of Health, and the ASU Biodesign Institute, could potentially influence future regulatory decisions regarding glyphosate use. Velazquez and his team aim to identify environmental factors contributing to the rising prevalence of cognitive decline and neurodegenerative diseases.
“Our goal is to identify environmental factors that contribute to the rising prevalence of cognitive decline and neurodegenerative diseases in our society,” Velazquez explained. “By unveiling such factors, we can develop strategies to minimize exposures, ultimately improving the quality of life for the growing aging population.”
Given that most Americans have been exposed to glyphosate during their lifetime, these findings suggest that current regulations may need reassessment to protect public health better.
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