What Did Arizona State University Researchers Discover About This Common Herbicide?
Arizona State University researchers discovered that even brief exposure to glyphosate, the world’s most widely used herbicide, causes brain inflammation that persists long after exposure stops. The study, published December 4, 2024, in the Journal of Neuroinflammation, found that mice exposed to glyphosate developed significant neuroinflammation associated with neurodegenerative diseases like Alzheimer’s. Researchers detected aminomethylphosphonic acid, a glyphosate byproduct, accumulated in brain tissue months after exposure ended, suggesting potential long-term human health risks from this chemical used on major crops, including corn, soybeans, and wheat.
5 Key Points
- The study found that glyphosate exposure in mice accelerated Alzheimer’s-like brain pathology
- Harmful effects persisted even after a 6-month recovery period with no exposure
- Approximately 300 million pounds of glyphosate are used annually in the United States
- Researchers detected the chemical’s byproducts inside brain tissue, confirming it crosses the blood-brain barrier
- Low-dose exposure near human acceptable limits still causes brain inflammation
How Does Glyphosate Enter and Affect the Brain?
The research team, led by Ramon Velazquez from Arizona State University’s Biodesign Institute and Patrick Pirrotte from the Translational Genomics Research Institute (TGen), conducted experiments over 13 weeks, followed by a 6-month recovery period. Their findings confirm that glyphosate crosses the blood-brain barrier, which typically protects the brain from harmful substances. This protective barrier usually blocks chemicals and toxins from reaching sensitive brain tissue, but glyphosate managed to penetrate it and remain present for months afterward.
“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 K. Bartholomew, PhD candidate and first author of the study.
The scientists tested both high-dose exposure and a lower dose near current acceptable human limits. The concerning part? Even the lower dose led to detectable brain damage in mice. This raises serious questions about whether current safety thresholds for humans are actually protecting public health.
Why Should We Worry About Inflammation That Doesn’t Go Away?
The research team discovered that glyphosate exposure triggered inflammatory markers in brain tissue and blood that remained elevated after the six-month recovery period. To put this in everyday terms, imagine getting a splinter that causes redness and swelling, but instead of healing when you remove the splinter, the inflammation continues for months afterward. This persistent inflammation in the brain could potentially drive the progression of neurodegenerative diseases like Alzheimer’s.
Mice exposed to glyphosate developed anxiety-like behaviors and died earlier than expected, matching what other scientists have found when studying rodents exposed to this herbicide. The team also found higher levels of Amyloid-β and tau proteins—the same substances that form the plaques and tangles seen in Alzheimer’s patients’ brains—in mice exposed to the herbicide.
“Our goal is to identify environmental factors that contribute to the rising prevalence of cognitive decline and neurodegenerative diseases in our society,” Velazquez said. “By unveiling such factors, we can develop strategies to minimize exposures, ultimately improving the quality of life for the growing aging population.”
Who Says Glyphosate Is Safe and Why Might They Be Wrong?
The EPA currently considers certain levels of glyphosate safe for human exposure. They maintain that the body minimally absorbs the chemical, which is mainly excreted unchanged. However, this new research directly challenges these assumptions by showing that glyphosate and its breakdown product aminomethylphosphonic acid can build up in brain tissue over time.
“Herbicides are used heavily and ubiquitously around the world,” said Pirrotte, associate professor at TGen 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.”
The U.S. Geological Survey reports that farmers and companies spray approximately 300 million pounds of glyphosate annually on American fields. The chemical doesn’t just stay where it’s sprayed—it travels through the air, builds up in soil, and contaminates surface water and groundwater. Most Americans have been exposed to glyphosate during their lifetime, with farm workers, landscapers, and agricultural employees facing higher exposure risks through breathing it in or absorbing it through skin contact.
Where Is Glyphosate Found and How Might You Be Exposed?
Glyphosate is most commonly known as the active ingredient in Roundup and similar weed killers. Since 1996, companies have introduced glyphosate-resistant genetically modified crops, and the use of this chemical has skyrocketed. Farmers now spray it extensively on corn, soybeans, sugar beets, alfalfa, cotton, and wheat.
While the EPA and FDA regulate glyphosate levels in imported foods, enforcement varies widely, allowing the chemical to spread throughout our food chain. The International Agency for Research on Cancer classifies glyphosate as “possibly carcinogenic to humans,” contradicting the EPA’s safety assessment.
For the average person, exposure typically happens through eating food with glyphosate residue, drinking contaminated water, or breathing air near recently sprayed areas. People living near farms or working with agricultural chemicals face higher exposure risks. The new research suggests even short-term exposure at levels currently considered “safe” might cause lasting brain damage.
FAQ
Q: What exactly is glyphosate, and where would I encounter it?
A: Glyphosate is the active ingredient in many weed killers, including Roundup. It’s the world’s most widely used herbicide, sprayed on crops including corn, soybeans, sugar beets, alfalfa, cotton, and wheat. You might encounter it through food residues, drinking water, or in the air if you live near agricultural areas.
Q: How does glyphosate kill plants but supposedly not harm people?
A: Glyphosate blocks a specific enzyme pathway in plants that produces essential amino acids. This pathway doesn’t exist in humans, which is partly why regulators considered it safe. However, this new study shows it affects mammals in different ways, causing inflammation and accumulating in brain tissue even after exposure stops.
Q: Who might be most at risk from glyphosate exposure?
A: According to the Centers for Disease Research, farm workers, landscapers, and others working in agriculture face higher exposure risks through breathing it in or skin contact. However, the study suggests everyone might be at risk through food residues, as most Americans have been exposed to glyphosate during their lifetime.
Q: How long do the brain effects of glyphosate last?
A: The study found that effects persisted even after a 6-month recovery period when exposure was discontinued. In human terms, long-term neurological damage might result from even temporary exposure, with inflammation continuing long after contact with the chemical has ended.
Q: What does this mean for current safety regulations?
A: This research challenges current safety assessments. The EPA considers certain levels of glyphosate safe, but the study found that even doses near accepted human limits caused brain inflammation in mice. This suggests regulators may need to reevaluate safety thresholds and testing methods that don’t account for these long-term neurological effects.
Q: Could glyphosate exposure contribute to the rise in Alzheimer’s disease?
A: The study found that glyphosate exposure in mice accelerated Alzheimer ‘s-like brain pathology, including increased levels of the proteins associated with the disease. While more research is needed to confirm the link in humans, the researchers suggest environmental factors like herbicide exposure may contribute to rising rates of neurodegenerative diseases.
Q: What can I do to reduce my exposure to glyphosate?
A: While complete avoidance is difficult due to its widespread use, you can reduce exposure by choosing organic foods when possible, using water filters certified to remove glyphosate, and avoiding the use of glyphosate-containing herbicides in your own yard or garden.
Citations
News Medical. (December 4, 2024). Glyphosate exposure is linked to lasting brain inflammation. News-Medical.net. https://www.news-medical.net/news/20241204/Glyphosate-exposure-linked-to-lasting-brain-inflammation.aspx
