Several years ago I was going to write a post about Roundup and glyphosate, its active ingredient, but decided against it because several very good science-based reports were produced by others. Unfortunately, those reviews were not directed towards gardeners and based on frequent discussions on social media, the message is still not getting through to the gardening community.
My goal in this post is not to do my usual deep dive into Roundup, but instead I want to give readers a summary overview of the facts along with references containing more details. I hope that putting all of the information in one spot will make it a useful tool for discussions in gardening social media groups.
Roundup vs Glyphosate
Roundup was originally produced by Monsanto and it contained glyphosate as its active ingredient. Most people recognize and use the name Roundup. Unfortunately, Monsanto (now Bayer) has decided that since this brand name is so well known, they could use it to promote other products, some of which don’t even contain glyphosate.
One Roundup product marketed in Europe is vinegar with no glyphosate, and some products contain both glyphosate and another herbicide.
We really should be talking about glyphosate and not Roundup.
Roundup and Monsanto
Conversations that go something like this, “Roundup is toxic because I hate Monsanto” are illogical.
If you hate Monsanto – that is fine. But your love or hate of the company does not change the chemical properties of glyphosate. One has nothing to do with the other.
Does Glyphosate (Roundup) Cause Cancer?
The general public is more convinced than ever that glyphosate (Roundup) causes cancer because of the recent court cases. I’ve discussed this in detail in Roundup (Glyphosate), Cancer and the Courts.
The result of a court case is the sum opinion of the jury, and it does not represent the scientific facts. There is no doubt that the majority of general public hate Monsanto and Roundup, and they truly believe Roundup causes cancer. But that belief does not make it true.
One of the largest agricultural human heath studies has been following workers using glyphosate, for 20 years, and reported, “Overall rates of cancer in the study remain lower than in the general population, especially cancers of the oral cavity, pancreas and lung.”
The science is quite clear on this, there is no evidence that glyphosate causes cancer and most global health and safety organisations agree. The following infographic was prepared by the Genetic Literacy Project, a group promoting truth in science.
The EU Joins the Group
Update: July 26, 2021. I just saw a report from the EU (European Community) that reviewed the science on glyphosate. This 11,000 page report, looking at over 20,000 studies, concluded that glyphosate is safe and does not cause cancer. The only danger they found was that glyphosate “causes serious eye damage”.
Why is this significant? The EU has banned glyphosate in many applications, on a purely political basis, but the average person used this as “evidence” that glyphosate was harmful and caused cancer. It is good to see that the EU scientific community has finally done a proper review. Hopefully, governments will now catch up with the science.
Glyphosate (Roundup) and GMO
A common argument agaisnt GMO plants is that it encourages the use of Roundup. These two issues are unrelated to one another.
Yes, there are some Roundup-ready GMO crops. But the majority of GMO plants have nothing to do with Roundup and they are not Roundup-ready. See GMO Myths – Understand the Truth About GMO Plants for more details.
You can be against Roundup and be for GMO.
Glyphosate (Roundup) Found in Drinking Water and Babies Milk
Studies have found glyphosate in drinking water and in mothers breast milk. The headlines claimed that this was a huge problem, but when you look at the details you realize that it’s a non-issue.
It’s all about the dose.
Our scientific instruments are so good these days that we can find just about any chemical in water and milk. I reviewed the report that found glyphosate in Spain’s drinking water and calculated that you would need to drink the equivalent of 1,000,000,000 bottles of beer, on a daily basis, in order to reach an unsafe level.
The levels found in the environment and in mothers milk are extremely low and of no health concern.
Glyphosate (Roundup) and Chronic Diseases
Some claim that glyphosate causes all kinds of diseases including, diabetes, neuropathies, obesity, asthma, infections, osteoporosis, infertility, birth defects and non-celiac gluten sensitivity. Many of these claims have been made by Samsel and Seneff.
Anyone who has followed the Roundup debate will recognize the name of Dr. Stephanie Seneff. She has made numerous claims about glyphosate which are quickly discounted by the scientific community “as outrageous use of science”. Dr. Seneff is a computer programmer with no experience in chemistry, plant science or health science. Her most recent claim is that glyphosate is a contributing factor of COVID-19.
Unfortunately, the general public eats up her publicity stunts.
A recent review of the claim that glyphosate causes chronic diseases found no support for the claim and went on to say “Our critical analysis of the commentaries published by Samsel and Seneff reveals that their conclusions are not substantiated by experimental evidence but are based on a type of failed logic known as syllogism fallacies. As Nobel Prize-winning theoretical physicist Richard Feynman famously said, “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.””
Glyphosate (Roundup) and Soil Microbes
It is commonly believed that glyphosate harms soil microbes. When glyphosate was added to soil it was found that “it was rapidly degraded by microbes, even at high application rates, without adversely affecting microbial activity.”
Glyphosate (Roundup) and Gut Bacteria
Numerous recent reports in the media and online claim that science has demonstrated glyphosate affects our gut bacteria, and if true could have serious health implications.
One of the reasons glyphosate is so safe is that it only affects a well understood biochemical pathway called shikimate, which is found in plants but not animals. This is the reason it is not toxic to animals. The shikimate pathway is found in some bacteria that live in our gut.
A recent study claims to have shown that glyphosate can affect these bacteria.
Marc Brazeau is the editor of Food and Farm Discussion Lab and is the Genetic Literacy project’s senior contributing writer. He has done a thorough review of the report claiming a link between glyphosate and gut bacteria and found that the data did not support the conclusions.
The study itself does say, “more studies will be needed to ascertain if there are health implications arising from glyphosate inhibition of the shikimate pathway in the gut microbiome”. The study did not reach any conclusions about glyphosates effect on our health, even though the news reported it with sensational headlines.
Another study found that even levels 50 times larger than the Accepted Daily Intake (ADI) set by European food safety agencies had very limited effect on gut bacteria.
Glyphosate (Roundup) and Bees
A study sprayed honeybees with a normal concentration of glyphosate and found no harm to the bees.
Some studies have looked at bee behavior after exposure to glyphosate, and have reported some learning disabilities in bees. The number of bees studied was very low, and 1/4 of those were lost during the study. Other studies have looked at exposure to very high levels of glyphosate.
Bees certainly have environmental and pest problems, but glyphosate has not been shown to be one of them.
Facts About Glyphosate
Here are some important facts about glyphosate.
- our skins absorb very little
- it undergoes very little metabolism in the body and is mostly excreted
- it has a very low toxicity; the oral LD50 in rats is 4320 mg/kg, significantly less than vinegar
- it quickly adsorbs to soil and becomes inactive
- it has a soil half-life of 50 days, which is short for a pesticide
- plant uptake from soil is minimal
Not Enough Testing!
The anti-Roundup movement is quick to claim that there has not been enough testing, and that the existing testing was done by labs hired by Monsanto. That is nonsense. Over the last 45 years there have been thousands of studies by labs all around the world.
At some point you have to accept the results.
I am a “snowflake” who agrees with Robert’s fact searching, I bite my tongue, and resisting the urge to bite back, with all kinds of names like “Trumpublican”; believe me, I can come up with some great ones! These are clear attempts to make this a political rant rather than a nuanced article about science and public health…an issue important to people of all political persuasions. I would encourage a policy that says, “Your comment will be removed if you engage in ad hominem attacks and name calling.” They add nothing, and derail the conversation. I have begun to select information sources that do this, because, as civilized humans, we ought to leave that behaviour in the school yard.
It is interesting to note that of all the Regulatory Agencies listed in the infographic (see Robert’s original article) only the World Health Organisation’s IARC describes Roundup as a Class 2A carcinogen (ie a probable carcinogen). But note that they class alcoholic drinks as a Class 1 carcinogen (ie proven carcinogen – with no doubt). There is a broad consensus that alcohol is responsible for 3% to 4% of all cancer deaths. So guys, choose your carcinogen!
There’s a depressing amount of willful ignorance and scientific illiteracy in this comment thread…
It is even worse on social media.
Are you saying that people are being wilfully ignorant of how dangerous this chemical is?
” At lower non toxic concentrations of Roundup and glyphosate (1ppm), the main endocrine disruption is a testosterone decrease by 35%”. https://pubmed.ncbi.nlm.nih.gov/22200534/
“Moreover, the proprietary mixtures available on the market could cause cell damage and even death around residual levels to be expected, especially in food and feed derived from R formulation-treated crops”. https://pubmed.ncbi.nlm.nih.gov/19105591/
“Our results indicate that although exposure to glyphosate and Roundup during in vitro maturation does not affect nuclear maturation and embryo cleavage, it does impair oocyte developmental competence in terms of blastocyst rate and cellularity”. https://pubmed.ncbi.nlm.nih.gov/32686734/
At the bottom of each of these reports are more with similar conclusions.These are only reports on first-level effects.
There are reports working on second-level effect. This is where it works in conjunction with other chemicals to cause deleterious effect.
“One of the more alarming possibilities that seems plausible given basic biochemistry is the idea that glyphosate facilitates the penetration of aluminum across the gut barrier”. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4093745/
If you ask anyone, if a single cigarette will kill you, everyone would agree that is not true. It used to be that the consensus was tobacco was safe. Now the consensus is that is unsafe. How many papers describing the dangers of a chemical must be read before you need to set aside the opinions of the “experts”.
“Are you saying that people are being wilfully ignorant of how dangerous this chemical is?” – no, I’m not. People believe this nonsense because they listen to a small group of people on social media who strongly believe this, and they have not taken the time to look at the evidence.
Your studies are lab tests done at higher levels of exposure, in very specific situations. There are now many studies that have looked at populations of people. One compared farmers who are exposed to glyphosate on a regular basis to people living in the city. The people in the city had higher rates of cancer.
As reported in the post, almost all global institutes who have no looked at the 20,000 plus research papers agree as reported in the post.
Who knows more – a guy on the street listening to social media with no science background, or hundreds of experts in the field?
You cannot discount the guy on the street. I have a degree in science but am not limited to that area. I attended university for ten years and have multiple qualifications since then. I taught college for decades. But that is irrelevant. A public school student who reads a single paper more than I, is more qualified. I am not an “expert” in the “glyphosate field” but I read multiple papers on the topic daily, because I am doing research on Vitamin D deficiency. You might think that there is no connection but certain chemicals keep recurring in the literature. The papers that I cite are from multiple countries and disciplines. Papers I have seen studied concentrations as low as 50 ng/L.
I doubt that anyone from those organizations read more papers than I do on a daily basis. A doctor works from 9-5 (or more) treating patients. How much time can they spend researching everything new being reported. The same applies to the member of those health organizations. They do periodic examinations of the literature. For instance Health Canada’s conclusion is:
“An evaluation of available scientific information found that products containing glyphosate do not present risks of concern to human health or the environment when used according to the revised label directions”.
Upon drilling down, further the 2017 evaluations are based on recommendation on research carried out in 2008. The 2020 recommendations is that it shouldn’t be used 8 weeks before harvest.This contradicts its use as a desiccant but that isn’t stopping farmers from using it for that purpose three days before harvest.
The Food Safety Branch 2015-16 rated a number of foods contaminated with the chemical. Products had concentrations as high as 20 ppm (Soybeans).
https://static.producer.com/wp-content/uploads/2017/04/CFIA_ACIA-9123346-v1-FSSD-FSSS-Glyphosate-Final-Report-15-16_0184101.pdf
It is also unfair to say that it goes right through you. One study showed that after ingesting the compound in healthy volunteers and taking urine samples for 100 hours, the slower phase half-life excretion ranged between 18–33 hours.
https://www.sciencedirect.com/science/article/pii/S1438463920306039
Most chemicals have affects that have nothing to do with fatality rates directly. If you follow how this particular compound works, it can mimic certain neurochemicals. Think of how micro-plastics emit a compound that act like a pseudo-estrogen. If you follow the pathways, Glyphosate goes down multiple directions and one of those disrupts the function of Cortisol. This can lead to insulin resistance and diabetes. It can lead to damage to the hippocampus resulting in impaired learning.
I am not saying that there is any research to support these suspicions. It is a little unethical to follow this line of research. It isn’t the only chemical that does this. What I am saying is that farmers must only use it according to the labels, and that it should not be used in untrained applications.
Perhaps you did not see my last comment. Many global organizations have done the review of all these papers, and have come to a unanimous conclusion – glyphosate is safe.
We are way past the point of cherry picking individual research papers – that has been done by hundreds of experts; EPA, world health organization. Canada Health and now the EU.
Now what we need is for the general public to start believing the science.
Hello Robert. I always look forward to your well carefully referenced articles. This is a sensitive topic that gets taken over by emotion and so much misinformation out there. I look forward to checking out your books.
I have only one very minor editorial comment. In your summary bullet points, “it quickly absorbs to soil and becomes inactive” I think you mean adsorb with a ‘d’. Spell check never picks those out for us.
thanks
Calling people who are genuinely concerned about their health “lunatics” does nothing for the debate. Let’s keep this at least polite, even if reason is sometimes absent.
Thanks Robert. Great article – and some of the responses have been hilarious. The lunatics certainly came out of the woodwork on this one! And, I guess that the measure of a decent logically-argued article is the degree to which it provokes irrational hysterics.
In reference to your article concerning glyphosate causing cancer, after I was diagnosed with multiple myeloma about 2 years ago I began researching the causes of multiple myeloma. At that time I found the following article on the ncbi.nim.nih.gov website “Multiple Myeloma and Glyphosate Use: A re-Analysis of US Agricultural Health Study (AHS) Data. Int J Environ Res Public Health 2015 Feb: 12(2): 1548 – 1559. The article concluded “…analyses of the full dataset provides no convincing evidence in the AHS for a link between multiple myeloma risk and glyphosate use.”
Based on this conclusion, I continued using Roundup to eradicate the weeds in my yard. I have been using Roundup two, sometimes three, times a year for several years to control the weeds. Generally, I have been cautious about exposure to the herbicide.
Recently, I found another article on the ncbi.nim.nih.gov website “Glyphosate induces benign monoclonal gammopathy and promotes multiple myeloma progression in mice.” J Hematol Oncol 2019 July 5, 12(1) 70. In the Abstract the article concludes “These data support glyphosate as an environmental risk factor for MM (multiple myeloma) and potentially NHL (non-Hodgkin lymphoma) and implicate a mechanism underlying the B cell-specificity of glyphosate – induced carcinogenesis observed epidemiologically.”
There appears to be a risk associated with the use of Roundup. In general (without specific reference to Roundup), I found the odds of a person getting multiple myeloma range from 1/132 to 1/161. I cannot say that the use of Roundup caused my multiple myeloma, but the chances of getting multiple myeloma does not justify its use. I have since stopped using Roundup.
…Did you actualy read the Wang et al
(2019) paper.
Did you miss the dose rate that was used?
1g/kg (w/v) is ridiculously high, and the authors evenake it a point to indicate that the exposure they used is extrely high, even when compared to provious studies.
If anything, this paper reinforces the finding that glyphosate exposure is not associated with any increased risk of cancer at or below the ADI.
I appreciate the topic and the comments. I am exhausted reading through, trying to piece and parse to gain knowledge. I don’t use RU. My former gardeners wanted to use it; I declined and paid them to weed by hand. Recently someone on FB posted a vinegar-epsom salt-dawn dishsoap weed killer recipe. Having all the ingredients on hand, I made up a batch and proceeded to spray on the weeds that spring up in the cracks in the old concrete. Two days later, those weeds are dead. I still need to pick them out by hand, but at least they are no longer holding on.
They are not dead, the roots will grow back.
Unfortunately, the use of Epsom salts in herbicides is very ineffective. All they are is magnesium sulfate, and plants can tolerate extremely high levels of them. This is why they’re used as fertilizer in some cropping systems (mainly organic).
What you’re left with is basically a contact herbicide that relies on the surfactant (soap) to aid the penetration of the acid through the waxy cuticle.
As this type of application is not transported by the plant, it’s ineffective against species with substantial root systems, which are unaffected.
Additionally, the lack of transport in the plant means that any tissue that is not directly exposed with be unharmed. For lager weeds, this can mean that, unless you ensure that you hit all the foliar surfaces, you’re not even going to kill all of the above ground tissue.
I read a bit of good news from Taiwan – the school curriculum now includes a subject to teach kids how to identify fake news, propaganda, myths and conspiracy theories. The western world would do well to do the same to stops us falling for all the nonsense written for the public about fluoride, roundup, the sodium bicarbonate cure-alls, injecting bleach, etc, etc.
https://time.com/4730440/taiwan-fake-news-education/
This should be part of a course, every year in school – at all grades.
You missed the mark again by citing the farm report. Farmers in general live healthier life styles and have less rates of certain cancer than the general public. You left out the data that farmers suffer elevated rates of non hodgkins lymphoma. It is a fact, and these poor farmers are so contaminated with glyphosate the residues can be found in their homes.
I think what you are doing to explore garden myths is amicable. But I’m not buying in to some of your garbage. My guess is a monsanto shadow company gave you some funding.
I will be unsubscribing.
Thanks
I agree with David. Monsanto is funding scientists but we need the truth.
Ah, let me guess, Zhang et al., (2019), right? The one that youted the 41% increase in NHL that made waves among the anti-biotech community, but when it hit the scientific community, barely made a ripple.
The funny part is that the authors themselves indicate that their findings are questionable.
“”However, given the heterogeneity between the studies included, the numerical risk estimates should be interpreted with caution.”
And what are those numerical risk estimates?
Why those are the Meta RR values they base the 41% figure on!
The authors analyzed 6 studies as part of this work, but those studies were wildly different in terms of the power of analysis for each.
In fact, the 5 case controll studies combined don’t come close to the AHS prospective cohort study.
By smashing all these together, they caused for there to be variability in the data sets. This variability reduced the ability of the methods to differentiate between treatment effects and natural population variance.
Hi David, I really do get a good laugh at snow flakes “I will be unsubscribing”. YES SIR that will teach Mr Palvis to dare to give a different perspective on your CNN,CBS,MSNBC et. al. derived cherished beliefs.