“Industrial secret” adjuvants. Another, another!
What does science say about the link between glyphosate and cancer?
In 2015, the International Agency for Research on Cancer (IARC), an intergovernmental cancer research agency under the World Health Organization (WHO), declared glyphosate probably carcinogenic to humans. According to a provision of the European regulation , a pesticide classified as probable or proven carcinogenic cannot be authorized.
Following this Circ statement, regulatory agencies around the world are seeking to assess the risk associated with glyphosate. But from France to New Zealand, via Japan and Canada, the opinions of national and European agencies are almost unanimous: the carcinogenic risk of glyphosate is improbable. On May 30, 2022, the European Chemicals Agency (EChA) considers that glyphosate is neither carcinogenic, nor mutagenic, nor toxic for reproduction. It only considers the product dangerous for the eyes of users and toxic for aquatic organisms – two characteristics which do not result in the automatic rejection of the authorization request.
The International Agency for Research on Cancer is therefore alone in the face of ten regulatory agencies. Should we then exonerate glyphosate? A scientific report published on June 30, 2021 counterbalances this position. Commissioned by the French government, the National Institute of Medical Research (Inserm) has produced a summary of the health effects of pesticides, and in particular glyphosate. Its conclusion is that “the presumption of a link between glyphosate and NHL [non-Hodgkin lymphoma, a cancer of the lymphatic system] is moderate”. In other words, Inserm recognizes that information on the carcinogenic risks of glyphosate exists.
What studies are taken into account?
A major difference explains these divergent opinions. Circ and Inserm base their opinions on studies published in scientific journals, reviewed by peers, while regulatory agencies, national or European, base their opinions mainly on unpublished studies, commissioned or carried out by pesticide manufacturers. . “The EFSA does not take sufficient account of academic research” admitted on November 8 an official from the European Food Safety Authority .
The genotoxic effect of glyphosate, that is to say its ability to damage DNA, is at the heart of the controversy. It is a major mechanism in the development of cancer. As one might expect, these two types of studies do not arrive at the same results. Only 1% of industrial studies reveal a genotoxic effect compared to 70% of scientific studies published in peer-reviewed journals .
Of the 53 studies on which the European Food Safety Authority based its opinion on glyphosate, only two studies are reliable from a scientific point of view.
What credibility should be given to these industrial studies? The European Food Safety Authority (EFSA) has provided access to those on which it based itself to renew the authorization of glyphosate in 2017. Two independent Austrian scientists scrutinized all the genotoxicity studies up to here kept secret. Result ? Of the 53 studies, only two studies are reliable according to them from a scientific point of view .
“If you subtract the studies that are unreliable and those that are of minor importance, then nothing is left.”, points out Helmut Burtscher, biochemist at the Austrian environmental NGO Global 2000. “National or European agencies do not seem to closely examine the quality of industry studies,” denounces Nina Holland, of the NGO Corporate Europe Observatory – which works in Brussels to make the lobbying actions of large companies visible.
“University studies are so little taken into account that in the end, only industry studies, with diametrically opposed conclusions, are integrated,” laments François Veillerette, of the Générations futures association .
What components and molecules are studied?
The weight of industrial studies is not the only factor in the divide between regulatory agencies and the Circ. “If everyone looks at the same thing, not everyone looks at it from the same angle,” explains Luc Multigner, epidemiology researcher at Inserm. While the Circ takes into account studies carried out on marketed products, i.e. formulations based on glyphosate, regulatory agencies generally focus on the pure substance. This difference is not trivial: “The products used are much more dangerous than the active molecules,” underlines Joël Spiroux de Vendômois, president of the Committee for Independent Research and Information on Genetic Engineering (Criigen).
If glyphosate is called an “active molecule”, the other components, considered neutral by manufacturers, are far from harmless. Combined in the same product, their toxic effect is reinforced: this is what we call the “cocktail effect”. Researchers have made the comparison: Roundup formulations have been shown to be 10 to 1000 times more toxic than glyphosate alone .
If the isolated substances are tested for two years, “the finished products are only tested for a few days”
The problem is that adjuvants are neither indicated – industrial secrecy required – nor truly evaluated. “It is always the so-called active substances that are tested and not the products used by farmers,” denounces Joël Spiroux from Vendômois. If the isolated substances are tested for two years, the time necessary to observe the long-term effects, “the finished products are only tested for a few days on the skin or conjunctiva and without a blood test to look for possible pathologies”, details the searcher.
In 2016, for example, the National Food Safety Agency withdrew from the market 132 formulations combining glyphosate with a coformulant, POE-Tallowamine. “Unacceptable risks, particularly for human health, cannot be excluded for these products,” the agency then indicated. These eminently toxic products could never have been put on the market if the Roundup which contained them had been tested in their entirety for two years,” regrets Joël Spiroux from Vendômois.
Are farmers using glyphosate more likely to develop cancer?
“There are elements that highlight a genotoxic potential, that’s obvious,” recognizes Luc Multinger, co-author of the Inserm expertise. But does this DNA damage really cause cancer in exposed people? One type of immune system cancer is particularly associated with glyphosate: non-Hodgkin lymphoma (NHL). On this subject, American researchers followed a cohort of more than 50 farmers and observed no link between exposure to glyphosate and the occurrence of this cancer.
Exposure to glyphosate increases the risk of developing the most common non-Hodgkin's lymphoma cancer by 36%
But the independent study of unprecedented scale by the AGRICOH consortium counterbalances these initial results. It took into account three different cohort studies, more than 300 farmers in total, including all 000 farmers in the United States. Result ? Exposure to glyphosate increases the risk of developing the most common type HLH by 50%.
In view of the literature, Inserm has changed its position since its last assessment in 2013. The presumption of a link between glyphosate and NHL has gone from “weak” to “medium”.Why not strong? “We made a judgment based on the existing data, but they are not sufficiently precise,” emphasizes Luc Multigner. For example, we do not know the quantities actually used by farmers. But be careful, it is not because the data does not exist that the risk does not exist,” underlines the epidemiology researcher.
Thus, new links with other types of cancers were highlighted in the latest Inserm expertise, such as multiple myeloma and leukemia, whereas they were not visible in 2013, due to lack of studies. Clearly, the more knowledge is produced, the more links can be asserted with certainty.
What are the other health effects?
“Unfortunately, pesticides do not only cause cancer, but a whole series of pathologies,” recalls Joël Spiroux from Vendômois. Glyphosate is no exception to the rule. If studies have focused on the carcinogenic nature of glyphosate, the links with other pathologies are much less known. Inserm also considers the risk that glyphosate causes respiratory problems in farmers, with “a presumption of a weak link given the limited number of studies”.
Glyphosate is also suspected of being an endocrine disruptor, that is to say a substance which disrupts hormonal activity, and thus causes harmful effects on human health, such as reproductive disorders. As for the carcinogenic risk, the European Food Safety Authority (EFSA) concluded on this subject that “glyphosate does not have endocrine disrupting properties based on the available information”. Inserm avoided the controversy by raising the issue in just a few lines in its recent summary: “Experimental studies suggest deleterious effects linked to a mechanism of endocrine disruption. »
A study carried out on rats shows that even at doses considered safe in the diet, the herbicide based on glyphosate induces endocrine effects and disrupts development . Another study showed for the first time that the endocrine disrupting effect of herbicides could be due not only to glyphosate, but also to the coformulants contained in commercial products .