Glyphosate is the active ingredient in numerous pesticides and weed killers, including Roundup, a product manufactured by Monsanto and used all over the world. Glyphosate, so not Roundup specifically, has now been listed by the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO) as a “probable carcinogenic”. Specifically, it is linked to non-Hodgkin lymphoma (NHL).
This happened in 2015, when the IARC officially classified glyphosate as such. This came after the review of a range of different studies, which looked at the impact of glyphosate on forestry and agricultural workers since 2001. This revealed that those who had frequent exposure to glyphosate had an increased incidence rate of NHL than those who did not have this exposure. Additionally, a full list of some 750 products worldwide was released in which glyphosate is found. The report also stated that glyphosate has contributed directly to the sharp increase of crop varieties that are genetically modified to resist glyphosate.
So How Does Roundup Causes Cancer?
Numerous studies have now shown that Roundup, because of its glyphosate content, can cause NHL and other forms of cancer. This has culminated into the 2014 scientific review that concluded this. This study, ‘Non-Hodgkin Lymphoma and Occupational Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients: A Systematic Review and Meta-Analysis’, was published in the International Journal of Environmental Research and Public Health. It brought together some 30 years of research into how 80 different pesticide active ingredients, spanning some 21 different chemical groups, are linked to NHL. See also Roundup Can Cause Non Hodgkin’s Lymphoma.
According to the study, pesticides tend to focus not so much on the ingredients, but rather on the targets. Hence, there are herbicides (plants and weeds), insecticides (insects), and fungicides (fungi). Yet, across all those products, it seems that farm workers, who have significantly lower mortality rates than the average population, did have higher incidence rates of cancers. According to the Roundup cancer study, glyphosate exposure can double the chances of someone developing NHL.
There have been numerous studies that confirm the findings of the 2014 one, including:
- A 2008 Swedish study in the International Journal of Cancer that determined a doubling of the risk of developing NHL within 10 years of glyphosate exposure.
- A 2003 study in the Occupational and Environmental Medicine publication that focused on Midwestern farm workers, who had increased levels of NHL as a result of glyphosate exposure.
- A 2001 study in the Cancer Epidemiology Biomarkers & Prevention, where Canadian researchers linked glyphosate exposure to NHL development.
The big question, of course, is how Roundup can cause cancer. So far, what is known is that:
- The number of exposures is significant, with more exposures increasing the chances of developing cancer.
- When exposure happened is also significant. The latency period has been shown to be less than 10 years.
- Roundup interferes with an enzyme found in plants, pets and humans alike. In humans and animals, this enzyme must function properly if it is to deal with the various microbiota in the gut. According to Monsanto, Roundup only affects the enzyme in the plants, however.
Research has shown that specific population groups, most notably park landscaping staff, golf course caregivers, landscapers, nursery employees, and agricultural workers such as farmers, are at greatest risk of developing NHL and this is linked to their exposure to Roundup. This is also confirmed by animal studies in which mice were more likely to develop rare tumors and cancers after having been exposed to glyphosate.
Lawsuits Against Monsanto
Because there have been various official statements that link NHL with Roundup exposure, numerous people who have developed NHL have filed lawsuits against the company. See Roundup Lawsuit Settlements Update.
Those lawsuits include:
- 50 residents of California, including Aiton, Baker, Behar, Kohn, and Norris.
- A class action representing plaintiffs from California, Florida, Illinois, New Jersey, New York, and Wisconsin, who state that the disruptive factor of Roundup in microbiota necessary for proper gut functioning is the underlying cause of NHL and other health problems.
- 40 residents of California who claim to have developed NHL as a result of Roundup exposure.
- 136 plaintiffs across the country who claim to have developed NHL as a result of Roundup exposure.
- Jack McCall’s family, who claim that Jack developed fatal cancer as a result of Roundup exposure. He worked as a farmer and developed a rare form of NHL.
- James and Brenda Huerta, who claim that Brenda developed NHL as a result of Roundup exposure.
- Christine Sheppard who claims using Roundup on her Hawaii coffee farm caused her to develop NHL.
- Two Texas residents who say they developed NHL as a result of Roundup exposure.
How to Determine Whether Something Causes Cancer
The difficulty with finding examples of how Roundup could cause cancer is that it is difficult to determine whether or not something causes cancer at all. This is why something is generally listed as a possible or probably carcinogenic, without describing the exact hows of how this happens. In addition, there are numerous national and international bodies that each have opinions on these subjects. Even when looking at the same evidence and answering the same questions, they often do not come up with the same answers. Glyphosate is a perfect example of this, because there continue to be numerous experts who state that there is no link at all between Roundup and cancer.
The classification of the IARC, which assessed that glyphosate is a probable carcinogenic, was incredibly controversial. However, as the IARC is part of the WHO, which is the global health organization, this particularly statement has been the basis of the majority of lawsuits against Monsanto. Additionally, since the first verdict has now come in, awarding Dewayne Johnson $268 million, it seems that the general consensus is to agree with the opinion of the IARC report.
It is also important to understand exactly what the IARC concluded. Specifically, they stated that “there was limited evidence of carcinogenicity in humans for non-Hodgkin lymphoma”, which was a statement related specifically to the glyphosate herbicide. The result of this is that they have now listed it within Group 2A, which means it is classed as a substance “probably carcinogenic to humans”. See also How Carcinogenic Are Roundup and Glyphosate?
The European Union’s Food Safety Authority (EFSA) also voiced their opinion that same year, in November 2015. They also reviewed whether or not glyphosate was carcinogenic. However, they focused specifically on food exposure to the substance and their conclusion was that it should not be classified as a carcinogenic. Specifically, they stated that “all the Member State experts but one agreed that neither the epidemiological data nor the evidence from animal studies demonstrated causality between exposure to glyphosate and the development of cancer in humans”. However, because this focused on glyphosate in foods, many feel it is not relevant to how Roundup could cause cancer.
Then, in this country, the National Toxicology Program (NTP) is being looked at for their opinion. The NTP is made up of various governmental agencies and organizations, including the NIH, the CDC, and the FDA. Their role is similar to that of the IARC but specific to this country. They maintain a full list of products that they classify as being probable or potential human carcinogens. Their list was last updated in November 2016, so after both the IARC and the EFSA reports, and did not list glyphosate as a known or potential carcinogen.
In May 2016, the WHO came together with the Food and Agricultural Organization (FAO), part of the United Nations. They met specifically to discuss whether or not glyphosate presents a threat to humans when it enters their system through food residues. Like the EFSA, however, the conclusion was that it is unlikely that glyphosate will cause cancer in humans when consumed as part of their diet.
All cancers are caused due to genetic mutations. These mutations can be aided by exposure to external factors and toxins such as cigarette smoke, asbestos, and, possibly glyphosate. How that works exactly is a matter for the scientific community. Manufacturers have a responsibility, however, to ensure people are safe from known carcinogenic materials. The problem is, however, that with a product used so widely across the world for over 45 years, and widespread disagreement on whether or not glyphosate is a carcinogenic at all, it becomes even harder to answer the question of “how” something causes cancer. That being said, with the latest verdict in the Dewayne Johnson case, it is possible that this question will soon be answered.
- Non-Hodgkin Lymphoma and Occupational Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients: A Systematic Review and Meta-Analysis (April 23, 2014). Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/24762670.
- Integrative assessment of multiple pesticides as risk factors for non-Hodgkin’s lymphoma among men (September 2013). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1740618/.
- Pesticide exposure as risk factor for non-Hodgkin lymphoma including histopathological subgroup analysis (October 1, 2008). Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/18623080.
- IARC Monographs Volume 112: evaluation of five organophosphate insecticides and herbicides (March 20, 2015). Retrieved from http://www.iarc.fr/en/media-centre/iarcnews/pdf/MonographVolume112.pdf.
- Glyphosate: EFSA updates toxicological profile (November 12, 2015). Retrieved from https://www.efsa.europa.eu/en/press/news/151112.
- Report on Carcinogens, Fourteenth Edition (November 2016). Retrieved from https://ntp.niehs.nih.gov/ntp/roc/content/listed_substances_508.pdf.