Glyphosate is one of most widely used chemical herbicides, but a new mouse study shows it has the potential to harm more than weeds. Researchers at Arizona State University found glyphosate can accumulate in the brain and trigger inflammation, which can remain long after exposure ends.
Inflammation in the brain is associated with neurodegenerative disease and can cause damage similar to what is seen in Alzheimer's.
Neuroinflammation was the most prevalent result of glyphosate exposure in the mice. Some experienced premature death, while other displayed anxiety-like behaviors. The symptoms even persisted after a 6-month recovery period that included no additional exposure to glyphosate. And a byproduct of glyphosate - aminomethylphosphonic acid, also accumulated in brain tissue which is raising concern about the chemical's safety.
The Environmental Protection Agency (EPA) considers glyphosate safe for human exposure because it is said to be minimally absorbed and then excreted. However, previous studies have shown glyphosate can cross the blood-brain barrier, which is a protective layer that is meant to keep potentially harmful substances from entering the brain.
"Our work contributes to the growing literature highlighting the brain's vulnerability to glyphosate," researcher Ramon Velazquez says. "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."
The U.S. Geological Survey says approximately 300 millions pounds of glyphosate is used annually in America. It is heavily sprayed on crops such as corn, soybeans, sugar beets, alfalfa, cotton, wheat and oats. As a result, it can be found throughout the food chain. It is also present in the soil, as well as surface and groundwater.
"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," Samantha K. Bartholomew says.
"Our goal is to identify environmental factors that contribute to the rising prevalence of cognitive decline and neurodegenerative diseases in our society," Velazquez says. "By unveiling such factors, we can develop strategies to minimize exposures, ultimately improving the quality of life for the growing aging population."
Click here to read more in the Journal of Neuroinflammation.