Glyphosate, the active ingredient in Roundup and similar herbicides, might affect certain mechanisms used by white blood cells to protect us against infectious microorganisms. This is suggested by
a study published in
Environmental Research by a team from Laval University.
Glyphosate is the most widely sold herbicide in the world. This product and its metabolites can be detected in 80% of the population.
Image Pixabay
"When glyphosate was marketed in the 1970s, it was believed to pose no risk to human health because it targeted enzymes specific to plants. Since then, numerous studies have suggested an association between glyphosate exposure and certain health problems, but there is still no consensus on the effects of this herbicide on human health," says the study leader,
Martin Pelletier, a professor at the Faculty of Medicine at Laval University and a researcher at the CHU de Québec - Université Laval Research Center.
Glyphosate might affect certain functions of the immune system, continues the researcher. "The common denominator of these problems is an exacerbated inflammatory response," he notes. "This prompted us to study the effects of glyphosate on neutrophils, the most abundant white blood cells in the human body and the first to arrive at an infection site."
To do this, the researchers isolated neutrophils from human blood and exposed them to three concentrations of glyphosate: the average concentration found in the urine of the adult population, the concentration reported among agricultural workers exposed to this herbicide, and the concentration in people who have poisoned themselves with the product.
What were the findings? "At all three tested concentrations, glyphosate does not kill neutrophils nor does it affect their activity level. However, our results indicate that it disrupts two mechanisms used by neutrophils to fight infectious agents," summarizes Professor Pelletier.
Indeed, the researchers observed an increase in the production of reactive oxygen species. "These are molecules, such as peroxide, that neutrophils produce to eliminate microbes after phagocytizing them. An overproduction of reactive oxygen species has detrimental effects on the body because they damage our own tissues."
The researchers also noted an effect of glyphosate exposure on the production of interleukin-8, a molecule that attracts other immune cells to an infection site. The level of interleukin-8 is naturally 50% higher in women's neutrophils than in men's. "In the presence of glyphosate, interleukin-8 production increases in men's neutrophils, but not in women's. Their levels then become comparable, which adds evidence to the idea that glyphosate is an endocrine disruptor," points out Professor Pelletier.
A neutrophil, in yellow, at the moment it phagocytizes anthrax bacilli. Once inside the cell, these bacteria are attacked by reactive oxygen species produced by the neutrophil. In the presence of glyphosate, neutrophils overproduce these molecules, which can damage our own tissues.
Volker Brinkmann Glyphosate is the most widely sold herbicide in the world. Between 1994 and 2014, annual usage surged from 35 million pounds (16 million kilograms) to 175 million pounds (79 million kilograms). "Glyphosate and its metabolites are detectable in 80% of the population," notes the researcher. "They are found in numerous organs, in the blood, and in human milk. The body eliminates these products within 48 hours, but we continually ingest them through our diet."
"Now that we have established that the functions of neutrophils can be disrupted in vitro by glyphosate, we want to determine if the same phenomenon is observable in people who are particularly exposed to this herbicide, such as agricultural workers. If so, this could affect their ability to respond to infections in addition to causing other health problems."
The study authors published in
Environmental Research are Pier-Olivier Leblanc, Yann Breton, Florence Léveillé, Philippe Tessier, and Martin Pelletier.