Glyphosate, the active ingredient in herbicides such as Roundup, would affect the immune response, in particular by disrupting the functioning of immune cells which are the first to mount the fight, warns a study published by a researcher at Laval University.
Although it was considered, when it was marketed in the 1970s, that glyphosate was safe for humans, numerous studies have since questioned this assumption and there is currently no consensus on the subject. effects of this herbicide on human health.
The head of the study, Professor Martin Pelletier of the faculty of medicine at Laval University, draws a comparison with cigarettes.
“It still took a long time before we realized that cigarettes are harmful to health,” recalled Mr. Pelletier, who is also a researcher at the Research Center of the CHU de Québec-Université Laval.
“So, with glyphosate which appeared in the 1970s and which is currently used extensively, well, the consequences, we will see them arrive there. »
Professor Pelletier and his colleagues were more specifically interested in neutrophils, the immune cells which represent the body’s first line of defense.
During laboratory experiments, researchers exposed neutrophils to three concentrations of glyphosate: the average concentration found in the urine of the adult population, the concentration found in agricultural workers, and a toxic concentration which could threaten life.
They first observed that exposure to glyphosate causes an increase in the production of reactive oxygen species in neutrophils. While this production is part of the normal functioning of neutrophils, too much production could cause damage to healthy tissues.
“It could contribute to the destruction of certain tissues or the weakening of certain tissues,” said Mr. Pelletier. It has been demonstrated in the past that [dérivés réactifs de l’oxygène] are very damaging. In an autoimmune disease like rheumatoid arthritis, for example, these are the [dérivés réactifs de l’oxygène] which will break down the cartilage, causing the bones to start banging together. »
Interleukin-8
The researchers also noted that exposure to glyphosate influenced the production of interleukin-8, a molecule that serves to attract other immune cells to a site of infection.
The level of interleukin-8 is naturally 50% higher in women’s neutrophils than in men’s. But upon exposure to glyphosate, men’s interleukin-8 levels rise to those of women, which could mean that glyphosate is an endocrine disruptor.
We must remember that women suffer more from autoimmune diseases than men, recalled Mr. Pelletier, and we cannot therefore exclude that exposure to glyphosate increases this risk in men.
“We agree that this still remains to be demonstrated,” he said, “but there is evidence in the literature that it increases chronic inflammatory diseases. There is an association that has been made for arthritis, for endometriosis in women. »
Glyphosate is the best-selling herbicide in the world. Between 1994 and 2014, the quantities used annually increased from 16 million kilograms to 79 million kilograms. Glyphosate and its metabolites are detectable in 80% of the population. They are found in many organs, in blood and in human milk. The body eliminates these products within 48 hours, but we continually ingest them through our diet.
Although some municipalities are starting to ban its use, we cannot expect the product to disappear from the landscape anytime soon. Consumers must therefore take their fate into their own hands, for example by looking for glyphosate-free herbicides.
“We buy food, we try to control our diet, to have fruits, vegetables, things like that, then we often forget what made it possible to produce these fruits and vegetables, so that they were exposed to pesticides, things like that, concluded Mr. Pelletier. So for me it is important that the consumer is aware of what they are going to ingest. There is a possibility that you have glyphosate in your food, and this glyphosate will have an effect on you, and it is important to know that. »
The findings of this study were published by the journal Environmental Research.