Curious Cook: Glyphosate, the free stuff we do not really want

  • Food News
  • Sunday, 24 Mar 2019

Despite the highly plausible health risks regarding alcohol, I still like drinking good wines. What I am less keen on is the extra stuff I am also ingesting with the wines, like a chemical called glyphosate.

A recent documentary on French TV highlighted that every wine they tested had detectable levels of glyphosate, a component of the herbicides commonly used at vineyards and most commercial crop farms.

Glyphosate was also found in varying quantities in the urine of every person they tested, so it appears that exposure to this ubiquitous compound is part of modern living for many millions of people. Therefore, this chemical is what this article will investigate.

One reason why glyphosate (also known as n-phosphonomethylglycine) is so ubiquitous is because the Monsanto patents expired in 2000 and now the compound is produced around the world by several other manufacturers. Since its introduction in 1974, it is estimated over nine billion kilograms of glyphosate has been sprayed on farmlands worldwide.

Should we worry?

A little research into how glyphosate works as a herbicide finds that the compound inhibits the shikimic acid pathway in plants. If you want to know more, glyphosate specifically obstructs the enzyme, 5-enolpyruvoylshikimate 3-phosphate synthetase, which is indirectly required by plants for the biosynthesis of essential aromatic amino acids such as phenylalanine, tyrosine and tryptophan.

The shikimic pathway is found only in plants, fungi and bacteria. Therefore, in theory, glyphosate is highly unlikely to be toxic to mammals, insects, birds, fish, etc.

Two opinions

At this point, it is worth noting two different, but important, opinions about glyphosate. One is the assessment by the influential IARC (International Agency for Research on Cancer, part of the World Health Organisation) that glyphosate is a Group 2A risk – this means the IARC classified it as “probably carcinogenic to humans”.

Most fruits and vegetables have traces of glyphosate. Photo: Karen Cropper/Flickr

This is the same group of risk as for red and industrially-processed meats which contain nitrites or nitrates. For more information, please read my article Processed meats: WHO says it's bad on

The other opinion is shared by the highly-respected European Food Safety Authority (EFSA) and the Environmental Protection Agency of the USA (EPA). Discounting the EPA for the moment, the EFSA report was particularly interesting as it specifically addressed the earlier findings of the IARC during a new assessment and still came out with the conclusion glyphosate is “unlikely to pose a carcinogenic hazard to humans”.

To complicate matters, on 11 August 2018, a US court awarded damages of US$289 million (RM1.17 billion) against Monsanto for allegedly causing a man to develop terminal non-Hodgkin's lymphoma due to the use of Roundup products which contain glyphosate. So, what is the reality?

The research

It turns out that everybody is a little bit right. The informative EFSA report provided an interesting clue in a paragraph which states, “Regarding carcinogenicity, the EFSA assessment focused on the pesticide active substance and considered in a weight of evidence all available information.”

In short, the EFSA report (and the EPA assessment) was based on testing only the compound glyphosate while the IARC status was based on products and formulations that contain glyphosate.


According to a University of Caen study in 2018, the ancillary chemicals added to glyphosate formulations make a huge difference to the toxicity of such products. A range of herbicides containing glyphosate were analysed, along with the surfactants, diluents and other chemicals added to enhance the efficiency of glyphosate.

Traces of glyphosate are found in most vineyards. Photo: Nat Welch/Flickr

This was not as easy as it sounds as US and EU packaging do not list additives in full if the producer deems them as “inert” substances, and there is little regulatory clout to demand proof of the “inert” nature of such additives.

But it is clear such additives have a very significant impact. Tests with glyphosate alone and formulations containing glyphosate (FCG) elicited wildly different responses – in test human cells, glyphosate alone generally had no effect but most of the FCGs were established to be highly toxic, killing human cells within 90 minutes.

This is a sobering finding, and one group of problematic additives identified is polyoxyethylenamines (POEA) derived from petroleum. But POEA is not the only contaminant found in FCGs - nonylphenol polyethoxylates (NPEOs), poisonous metals such as arsenic, chromium, nickel and lead are also often found in FCGs. When applied persistently, these chemicals and metals remain in the ground, can contaminate future crops and also leach into groundwater causing further damage via pollution.

Oddly, the study also very surprisingly found that glyphosate is very much less toxic for plants than the additives in FCGs. After numerous tests, the study stated plainly glyphosate is usually the least effective herbicide chemical in the tested FCGs and that the bulk of herbicidal effects were due to the additives in FCGs, and not glyphosate itself.

French farmers

The Caen study might tie in with another multi-institute French study in 2010 which researched the link between Parkinson’s Disease (PD) with persistent occupational exposure to chemicals such as herbicides, insecticides, fungicides, herbicides, rodenticides, crop treatments, etc.

The study covered 237,917 French farming workers in 2007, and found that for all age groups investigated, the incidence of PD was roughly double that of the general French population. However, as stated, the study does not only cover herbicides, and indeed the research only confirms there may be serious dangers involved with farm chemicals in general, at least in relation to PD.

Regarding cancers, the evidence is less conclusive. Large scale studies like the Agricultural Health Study (AHS) in the USA and the French Agriculture & Cancer (AGRICAN) study found that mortality rates from most cancers were not abnormal compared to the general public. Some deviations applied to multiple myeloma, lip and prostate cancers, and even so, they do not affect the overall death rates of farm workers.

This may be due to the “healthy worker” effect as farm workers are more physically active which tends to make them healthier than average. The favourable effects of such healthier lifestyles may conceal, mask or counter the negative effects of exposure to farm chemicals. As such, the French National Institute of Health and Medical Research warned against making “simplistic” assumptions from the data.

Analysis of the AGRICAN data also suggested an increased risk of PD, especially with users of dithiocarbamate-based fungicides, rotenone and the herbicides diquat and paraquat. Curiously, glyphosate was not amongst the compounds analysed for some (unknown) reason.


Farmers are constantly and often heavily exposed to pesticides, but so too are consumers who are exposed to these chemicals via residues on fruit, vegetables and meat. There is not much good that comes from ingesting pesticides (such as insecticides) because in sufficiently high doses they are almost always seriously toxic to humans.

Even everyday breakfast meals like cereal have glyphosate. Photo: Ben Siedelman/Flickr

However, we are discussing glyphosate today and the weight of evidence suggests it is not onerously toxic to humans by any scientific measure. It may affect the shikimic acid pathway in human gut bacteria and kill some of them, but this also happens when ingesting many other compounds, such as artificial sweeteners or simply unbalanced quantities of junk food.

The warning

So it appears the main and very real dangers of glyphosate lie within the chemical additives in FCGs. In this respect, it may be suggested consumers are being starved of data they need to make an informed choice about foods treated with glyphosate and other compounds.

At present, glyphosate is found in foods ranging from breakfast cereals through to fruits, vegetables and many meats. While probably not toxic by itself, the presence of glyphosate may be a warning indicator of the likely toxic compounds that accompany it.

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