Hi friends! Today on the blog we are chatting about glyphosate. Glyphosate is a widely-used pesticide that has recently been in the news as Monsanto (Bayer) is facing lawsuits that claim glyphosate has caused cancer. Today we are going to discuss what glyphosate is, and what is known about its safety. I hope you are as excited as I am to explore this intersection of environmental health science and food and nutrition!
If you are interested in reading more about pesticides, I have a whole blog post about chlorpyrifos here. And you can learn more about the benefits and limitations of organic farming in this post. Furthermore, I have a review of existing evidence on GMOs and their safety here.
What is glyphosate?
Glyphosate is a widely used herbicide (pesticide). It has been registered as a pesticide in the US since 1974 and is used to control weeds and grasses in commercial, agricultural, and residential settings. It plays a role in food production, including the control of pests in the production of fruits, vegetables, nuts, corn, soybeans, leafy greens, cereal grains, herbs and spices, sugar, and oilseed crops, among others. It’s also used in parks, pastures, turf grasses, etc.
Glyphosate is used in products such as RoundUp and is available for consumer purchase for at-home applications.
Glyphosate has been subject to controversy. It was introduced by Monsanto (now Bayer), which subsequently developed genetically modified crops that were designed to withstand the pesticide. Many people questioned the motives behind these innovations.
How are people exposed to glyphosate?
The general population may be exposed by skin contact to products or soils that contain chemical residue. People may also be exposed to glyphosate at work, especially if they work in lawn servicing or agriculture.
And, as a result of its widespread use, glyphosate is present in a wide variety of foods at low levels, so many people are exposed to glyphosate via food.
Are there any health risks from glyphosate exposure?
It depends on who you ask.
According to the WHO International Agency for Research on Cancer (IARC), glyphosate is “probably” carcinogen (meaning, cancer-causing) to humans. They based this conclusion on three studies, and found “strong evidence” that glyphosate can cause DNA damage in cells, which is among the factors that can prompt cancer. An additional study in the report found that mice fed glyphosate got more tumors.
According to the EPA, glyphosate is “not likely” to be carcinogenic to humans at doses humans are exposed to. However, the Office of Research at the EPA submitted a report that said that the initial reviewers had not followed proper protocols, and that the evidence could be deemed “likely” carcinogenic or “suggestive” of evidence of carcinogenic classification. Still, the EPA put out their statement in 2017 that claimed glyphosate had no risk to public health.
Why these different findings? Well, as noted on the EPA’s website, they had access to a larger database, with many studies that are not public. The IARC only used publicly available studies to make their ruling, which allows for transparency into the quality and integrity of the science. Furthermore, the IARC was looking to see whether or not glyphosate could cause cancer, and the EPA was focused on the question of how likely developing cancer from exposure was.
In 2019, the US Agency for Toxic Substances and Disease Registry (ATSDR) opened a length profile on glyphosate for public comment.The report made their statement on cancer-causing effects based on three meta-analyses and some case-report and epidemiology studies.
The meta-analyses suggested a link between glyphosate use and cancer, as did the case-control and cohort studies; however, as the authors note, the individuals in the case-control and cohort studies were also likely exposed to other pesticides.
The ATSDR also found that ingestion of glyphosate is also associated with eye irritation, nausea, vomiting, and mucosal damage in humans, and decreased body weight, decreased red blood cell counts, and reproductive effects in rodent studies.
In Europe, glyphosate is approved until December 15, 2022. A 2019 study by the Germany’s Federal Institute for Risk Assessment concluded that glyphosate did not pose a cancer risk, however, it has been reported that the approval was based on text plagiarized by Monsanto.
The California Office of Environmental Health Hazards Assessment has added glyphosate to its list of chemicals that likely causes cancer. Monsanto tried to sue for this, but the case court was thrown out.
A 2020 review of existing evidence of animal studies conducted on glyphosate and cancer found consistent evidence of exposure levels and several types of cancer, including hemangiosarcomas, kidney tumors, and malignant lymphomas.
There was also a 2019 study that examined 14 pesticides and non-Hodgkin lymphoid malignancies in three large cohorts of agricultural workers In the US, France, and Norway found an association between glyphosate and Beta-cel lymphoma.
A 2016 review of observational studies that explored the impacts of glyphosate on pregnancy found an association of glyphosate exposure and increased rates of ADHD in children. Although, as the authors note, further research is needed to determine causality.
And a 2019 paper in the Environmental Science Europe argued that the EPA made their decision based on evidence that disregarded the genotoxicity of glyphosate on cells.
My hot take (which nobody asked for):
I will say that based on what I have read, it seems like glyphosate is a less harmful alternative to something like, say, DDT, which builds up in the environment and has an array of known health impacts. It also has a lower LD50 value (a value that indicates how large of a dose is necessary to kill half a group of animals via toxicity) compared to some other toxic chemicals.
However, I am yet to be convinced it is as safe as the public was led to believe. The fact that Monsanto has fought so hard to have data they funded included in US rulings gives me pause.
Most of the independent, non-industry funded studies, reviews, and meta-analyses show cause for caution, or at the very least, further research for a definitive answer. I think the primary question that needs to be addressed is: how large of a risk does this pose at normal exposure levels over time, and also, how can acute large exposures (from accidents, occupational exposures, etc) impact health?
Until theses questions are answered with some degree of confidence, I would avoid using it in residential settings.
That said, when banning a chemical, you have to be aware that oftentimes, another similar chemical will pop up in its place. Which is why I advocate for stronger testing before these sorts of insecticides can be rolled out for commercial use.
Personally, I have toured Monsanto (or Bayer’s) agricultural headquarters in California as part of a journalism trip and have interviewed many of their representatives and scientists about GMOs and pesticides. They seem to be working very hard to improve public opinion of what they do, and they were very courteous to me. It was interesting to speak to them, but the trip did not in any way sway my objective opinion of glyphosate use.
To be clear, I do support the use of GMOs and I do not consider organic farming to be a panacea, however, I believe there is a need for more stringent, unbiased, non-industry-funding testing of chemicals and pesticides before they are approved for wide distribution.
Glyphosate needs more independent review, and governing bodies need to make unbiased decisions without industry influence (or funding). And, in general, I am an advocate of more stringent regulation on pesticide and chemical use in the United States (and elsewhere).
Glyphosate is a widely-used pesticide that has long been marketed as safe. However, emerging independent research has cast doubts on its safety.
If you liked “Is Glyphosate (Round Up) Safe?” you may also like:
- What is Chlorpyrifos? Is chlorpyrifos dangerous? Here’s what you need to know about the most widely-used pesticide in the US
- How does CO2 Contribute to Increasing Temperatures?
- What are VOCs? How do VOCs Impact Human Health?
- Is organic food better for the environment? What about grass-fed meat?
- What are flame retardants? Are they safe?