Does glyphosate impact human health? This is where we stopped our previous conversation. It’s the question that has been on my mind since I first learned that glyphosate is an antibiotic. It’s the question for which I still don’t have a proper answer. It’s a question that has provided me with many thoughts and additional questions.  To put it quite bluntly: scientific literature doesn’t provide any clear answers. What do you do when there is no clear evidence? We put on our science hat and conjecture potential hypotheses. That’s my goal for today. Structuring my thoughts on paper rather than reviewing inconsistent scientific findings. What’s the point of that? It should help identify areas where more research is needed while letting my brain wander freely.

To start. A lot of my thoughts are based on my understanding of glyphosate use, mechanism of action and more. These are things I reviewed previously. If this is new to you, it would be best to go back and read the previous blog.

If our human health is to be at risk, it implies that there should be a significant exposure to glyphosate to begin with. Considering the approximate 1.35 million metric tons of glyphosate that is used annually, it seem like ‘yes’ is the most straightforward answer. But… and there is always a but… not every human is exposed equally. Image working as a farmer, riding your tractor spraying glyphosate on your crops to kill the weeds. Now imaging living in the middle of a city with the closest green scenery the city park. It doesn’t require a genius to figure out that the farmer will likely have a much higher exposure. We need to take this into account for our thought experiment. Similarly, direct exposure to high concentrations vs. long term exposure to lower concentrations is another point to be aware of. Finally, the ‘source’ of contamination comes into play as well. I hinted in the previous blog that fresh food can be contaminated with glyphosate residues. And if it’s in our food, than our gut microbiome might get exposed to something harmful. Well… we’ll just read the label which needs to states what contaminants are in the food we buy. Problem solved! Yes… if such a transparent food label would actually exist…

Lots of different perspectives to explore here, let’s try and find clarity on these topics one by one.

Glyphosate’s Shadow: Exploring Its Controversial Role in Cancer and Gut Health

There is an elephant in the room that we need to address first. Glyphosate has been in the press, and not in a good way. Glyphosate was recently labelled as probably carcinogen by the International Agency for Research on Cancer (IARC), a subdivision of the WHO. However, other relevant agencies like the Environmental Protection Agency (EPA) in the US and European Food Safety Authority (EFSA) have refrained from labelling glyphosate as probably carcinogen. One contributing factor here is that although a compound can be carcinogenic, without exposure there is no risk. This is the stance of the EPA and EFSA: based on their assessment the typical exposure levels to humans were determined to be within ‘safe limits’.

While my knowledge of oncology is limited, what surprised me most is the type of cancer linked to glyphosate exposure. Non-Hodgkin lymphoma, a cancer originating in our lymph nodes and part of our immune system (which I am more familiar with). More specifically, it affects a cell type that we call lymphocytes, one of the many soldiers of our immune system. Normally, these immune cells are very tightly regulated. Although they help protect us from many bad things, if not ‘silenced’ on time things tend to get out of control quickly. Part of the regulation and training of immune cells is associated with our gut and gut microbiome. Metabolites produced by our gut microbiome, such as short chain fatty acids (SCFA) and tryptophan, act directly on the metabolism of our immune cells. Thus, the good microbes in our gut regulate the function of our immune system to fight the bad microbes that could kill us. That sounds odd, but hey it works! The primary outcome of this strange relationship? Promoting immunosuppressive function while inhibiting proinflammatory processes in our immune system. Doesn’t sound like a good idea to start messing with this process right? If we would, for example by meddling with the microbial diversity in the gut, it would likely lead to adverse health outcomes over the course of time. If we close this loop and bring things back to glyphosate, there are two ways in which it’s mechanism of action intersects with this process. First, glyphosate is officially labelled as an antibiotic so it can directly impact microbial diversity in the gut (upon exposure). But, more interestingly, glyphosate’s action on the shikimate pathway disrupt the synthesis of aromatic amino acids and ‘tryptophan’ is one of those aromatic amino acids. It’s an essential one, humans can’t make tryptophan in their body. Thus, our gut microbiome passively produces tryptophan on top of our dietary intake of  this essential resource. Disrupting this may tip the balance and reduce the amount below our needed threshold. In turn, this has the potential to disrupt tryptophan’s regulatory function on the immune system, pushing it towards a proinflammatory state (which happens to be an important risk factor associated with Non-Hodgkin Lymphoma).

Whether the above thoughts provide a plausible theory on how glyphosate may cause Non-Hodgkin Lymphoma is questionable. But it has a ring to it. The reality is that biology is always much more complicated. Our understanding of the gut microbiome and its role in human health is still extremely limited. Nevertheless, we are living in a time where we are observing the incidence of many other immune and inflammatory related diseases increase rapidly. The common theme that keeps surfacing, disrupted gut microbiomes and immune function (but that’s a topic for another day).

So, our gut microbiome produces things that regulate the immune system and those processes could potentially be involved. But we don’t eat glyphosate, your theory is flawed.  Correct, we don’t eat glyphosate… at least not intentionally. But what if we simply didn’t know we were consuming it? We’ll need to dig a bit deeper and expand our thought experiment.

Unseen Dangers: Glyphosate in Our Diet and Its Stealthy Impact on Health

For glyphosate to interact with our gut microbiome, it needs to reach our gut first. As I can’t imagine anyone drinking glyphosate solutions willingly, a more likely exposure route would be through contaminated sources like drinking water and food. So how do we know if all of us could have an ‘exposure’? Two options. We could try to detect glyphosate in clinically relevant patient samples (like urine, where glyphosate shouldn’t be) or alternatively, we could try to detect glyphosate in the food we consume (where it shouldn’t be either). What’s behind door number 1? Glyphosate has been detected in urine of non-occupational users, i.e., non-farmers, at concentrations of approximately 11.5pg/mg. It may not sound like much but the baseline should be 0… Furthermore, degradation products of glyphosate, like Aminomethylphosphonic acid (AMPA), were found in human hairs. This indicates long term exposure to glyphosate and accumulation over time. Do you still want to know what’s behind door number 2? Well, it doesn’t get much better… toxic screening identified glyphosate residues on nearly all food products we consume. But why? Well, we spray glyphosate on almost all of our crops, unless they are grown organically…

Have we been eating antibiotics without knowing it! It’s a scary thought indeed and you will likely want to figure out which foods are the worst. At least, that was my initial reaction. Now, I don’t plan on listing all the different foods and their glyphosate detection levels, this is outside the scope of what I want to discuss here.  Just know that some regulatory agencies are monitoring this precisely. So I can’t eat those foods with high glyphosate concentrations anymore right? Well… of course you can. It’s not just about the food with the highest detection, the overall nutritional value of the food and the relative contribution of that food source to our overall diet is what matters most.

So how much glyphosate do we consume? Based on the ‘official’ regulatory viewpoints, whatever we consume is below the threshold defined as acceptable daily intake. But… there is one major problem. There is no standard daily intake: ever regulatory agency uses a different set of rules to define what is acceptable. One common theme though is that acceptable daily intake is mostly expressed as an amount (mg) per kilogram (kg) of body weight. This is where we can start our calculations but there is also another problem with this unit of measurement. Our ‘weight’ of glyphosate consumed per kg of body weight ignores the reality that glyphosate will not be distributed across our body weight equally. Glyphosate is deposited in full in our gut and thus our gut microbiome has to endure the full force of that exposure. If you take a typical Western diet, one would consume 0.117-0.133mg of glyphosate per meal (if my mathematics skills don’t fail me). We wouldn’t even see this amount on a spoon, thus this doesn’t matter. True, if there was a single exposure. The reality, 0.117-0.133mg per meal for an average of 3 meals per day, or 21 meals per week, for 52 weeks within a year… . In a hopefully 80 year healthy life, you would be consuming about 10kg of an antibiotic in full ignorant bliss. Now that’s food for thought.

The real challenge is knowing what low dose exposure means for our health. This is where scientific literature fails us today. The only study that explored this demonstrated an increased risk of non-alcoholic fatty liver diseases, a rapidly expanding health problem in. But… it was a study conducted in rats.

Glyphosate: Navigating Between Caution and Adaptation

What to make out of all of this? Should we be worried? Well yes, and no. The challenge is that little rigorous scientific evidence is available, resulting in hypothesis based thinking. Even when glyphosate would have a strong negative impact on our gut microbiome, our gut microbiome isn’t a pushover either. Its adaptable and if you provide it with the right tools & food sources, it will work miracles for you. Our strength moving forward? We now know that glyphosate is an antibiotic. The awareness allows us to make conscious decisions to adjust and introduce change if we feel it’s needed. In the end, we will need to rely on our own awareness as glyphosate isn’t going anywhere any time soon.