A pesticide that has been found in breakfast cereals, oatmeal and orange juice can cause dementia symptoms within weeks.
The herbicide glyphosate, which is the active ingredient in RoundUp, has long been linked to cancers and nerve damage. But much of the previous research has focused on looking at people who interact with it every day, such as farm workers.
The new study, conducted in mice, suggests that even small amounts of exposure can have lasting effects.
Experts found that rodents that received treatment for about three months experienced Alzheimer’s-like brain changes that persisted for months.
By dissecting the brains, the researchers saw that the chemical itself had entered the delicate brain tissue, where it likely caused inflammation, causing the nerves and brain tissue to break down, leading to the changes they observed after six months.
Patrick Pirrotte, author of the study and director of City of Hope, said: “These findings highlight that many chemicals we commonly encounter, which were previously considered safe, can pose potential health risks.”
Foods containing glyphosate include Quaker oatmeal, Cheez-It and Tropicana orange juice, according to a separate analysis by Sokolove Law, a personal injury and illness law firm.
A 2023 analysis by illness and personal injury law firm Sokolove Law compiled a list of products that had tested positive for glyphosate in the past. In addition to food, they also said the chemical was detected in cotton products and bottled water.
Previous studies have focused primarily on dosing mice with high levels of glyphosate. Only certain humans, such as farm or factory workers, are typically exposed to high levels of the herbicide; The average person is probably exposed to much smaller amounts of the chemical daily, if at all.
According to the United States Geological Survey, about 300 million pounds of the chemical are used in the country each year in products such as corn, soybeans, oats, alfalfa, cotton and wheat.
From there, it can accumulate in soil, water, or stick to crops as they are processed into food.
The CDC estimates that about 81 percent of Americans had been exposed to glyphosate in 2014.
Studies of this type led the International Agency for Research on Cancer to classify glyphosate as “possibly carcinogenic to humans,” but the EPA still approves its use and considers it safe.
It is banned or restricted in European countries such as Germany, Portugal and Spain.
Few studies have examined the impact that lower levels of prolonged exposure to the chemical might have.
That’s what the new research set out to examine. The article included researchers from Arizona State University and City of Hope, a private research center in California, and appears in the Journal of Neuroinflammation.
They fed mice two levels of glyphosate: a high level and a low level that would be closer to the levels at which humans come into contact with the pesticide.
The mice were fed their dose every day for 13 weeks and then the researchers stopped adding glyphosate to their diet and simply observed them for six months.
According to previous research, even six months after the researchers stopped feeding the mice the pesticide, high levels of glyphosate caused the mice to develop brain inflammation and Alzheimer’s-like changes.
However, the researchers found that there were similar, although less pronounced, changes in the brains of mice that were fed low doses of the chemical.
The researchers write that this inflammation could lead to symptoms seen in dementia, where healthy brain cells become clogged with sticky plaques leading to massive cell death and eventually memory loss.
This could help explain why we’ve seen an increase in memory-robbing conditions in recent decades, Dr. Velázquez said.
Glyphosate has been used since the 1950s. It became more popular in 1996, when genetic modification techniques became more advanced, allowing scientists to make crops resistant to it.
Professor Pirrotte said: “Herbicides are used intensively and ubiquitously throughout the world.”
Because of how common they are, Dr. Velázquez said: “our goal is to identify the environmental factors that contribute to the increasing prevalence of cognitive impairment and neurodegenerative diseases in our society.”
About 7 million Americans live with Alzheimer’s, and that number is expected to increase to 13 million by 2050, according to the Alzheimer’s Association.
This projected growth makes it essential that science investigate many possible causes of the disease, the study authors said.
Samantha Bartholomew, a doctoral candidate at ASU and author of the study, said: “My hope is that our work prompts further research into the effects of glyphosate exposure, which may lead to a re-examination of its long-term safety and such perhaps spark a debate about other common toxins in our environment that can affect the brain.
Still, they warned, since the research was conducted in mice, it is not certain that what was observed in this study is the same in humans. More research is needed.