New research from Arizona State University finds exposure to a common herbicide can cause problems in people’s brains. The active ingredient, called glyphosate, can cause brain inflammation, which increases the risk of neurological illnesses.
Dr. Ramon Velazquez, an assistant professor at ASU and the Neurodegenerative Disease Research Center, joined The Show to discuss, starting with how commonly used glyphosate is.
Full conversation
DR. RAMON VELAZQUEZ: So, glyphosate is, is very, very ubiquitously used. It was first developed and used in 1974 as an herbicide, and it's a very, very effective, effective one. Now, if we look at the numbers in the year 2020 and, and beyond, we find that approximately 3 million pounds are used in the United States every year and this doesn't also, this does not include usage, for example, on roadways by consumers at home to control weeds, etc., which includes approximately another 20 million pounds. So, so over 300 million pounds total, I would say more along the lines of 320 million pounds per year.
MARK BRODIE: That seems like an awful lot.
VELAZQUEZ: Yes, it is.
BRODIE: And as your research shows, it does not seem as though this particular chemical is all that good for us.
VELAZQUEZ: Yeah, so, you know, what we are interested in understanding in my laboratory with our collaborators is what are some of the potential effects that this herbicide can actually have and specifically in the brain. We are neurodegenerative disease researchers, and it kind of goes back to the history of why the use is, is so high and why glyphosate is used in the first place.
The idea is that it's not able to be metabolized by mammalian species, humans, rodents, animals. However, research has actually shown that mammals do have the ability to process glyphosate to what's called AMPA. AMPA is a metabolitic glyphosate, which can be processed or metabolized by bacteria in the gut microbiome, which is a very, very important component of mammalian species that mediates a lot of our bodily functions. And what we're finding is that now in two papers that we published in my lab with collaborators, is that glyphosate does in fact have the ability to get into the brain.
So, the brain is protected by what is called the blood-brain barrier, essentially vasculature, blood vessels that don't allow things to go into the brain unless they need to go in. We have now found that glyphosate can actually go into the brain and so can AMPA. And what we found in our most recent study is that even a short exposure, exposure time of glyphosate has the ability to accelerate a lot of the pathologies that you find in disorders such as Alzheimer's disease and also increasing inflammation, which can harm healthy tissues throughout the body and in this case what we examine the brain.
BRODIE: Yeah, I was curious about what exactly glyphosate does once it enters the brain. It sounds like it potentially sets people up for maladies later on.
VELAZQUEZ: Yes, so what we've actually found, I think one of the most common links of what we've identified is that life and state has the ability to initiate inflammation, right? And inflammation is essentially a mechanism that occurs that releases these molecules that are there to really protect healthy tissue. But if they're released in a high amount and chronically they can actually hurt healthy tissue.
And what we're finding in our most recent study is that even after an exposure of glyphosate, followed by a very long delay, and even then, while glyphosate wasn't present, AMPA was. And there are studies showing that AMPA in and of itself is as toxic as glyphosate and led to an increase in this neuroinflammatory response in the brain, which is typically what you find in many neurodegenerative disorders like Alzheimer's disease.
BRODIE: Are there particular groups of people that might be most at risk here depending on maybe the number of instances of being exposed or the duration of being exposed, or does that not really matter that much?
VELAZQUEZ: You know, this is a great question, and it's really, you know, and it highlights a point of what we want to do moving forward, right? We are particularly interested in understanding whether individuals that live in rural communities have an increased risk potentially of some of these ailments, specifically because agriculture communities, which are typically found in in cities, are at a higher risk of potential exposures because they are on essentially areas that are highly exposed to glyphosate because of the agriculture within those actual locales.
So we are actually currently collaborating with a group over at the Translational Genomics Research Institute. Where we are going around to different cities in Arizona trying to understand whether the exposure rates of individuals that live in rural communities might be higher than those that live in urban cities.
And why is that? If you look at the instances of cognitive decline, the loss of the intellectual abilities and learning and memory, for example, as well as incidence of Alzheimer's disease, you find that those communities are particularly at higher risk of developing those disorders.
BRODIE: Do you think at this point you could draw a straight line? Let's say that there's an agriculturally heavy community that also maybe has more dementia, Alzheimer's than you would otherwise think. Can you draw a straight line from glyphosate to that?
VELAZQUEZ: I think more research is needed, and I think that's what our, what we are doing next, as I just mentioned. We need to understand whether those communities that are in these rural cities that have higher instances of these disorders are actually being more exposed to glyphosate. And also what we need to further understand is that what dose we are finding a lot of these effects occurring, right?
We need to understand what the exposure rates are in these specific cities and then further, further identify whether they're actually contributing to some of these disorders that we're seeing that are on the rise in rural locales.
BRODIE: Is there a danger to people eating the food that might have been sprayed or in close proximity to, to this chemical as well?
VELAZQUEZ: Well, what, what we can say is that if you look at some of the prior studies that were, that have been done, a lot of these studies actually have, have come out in the last couple of years, two or three years. What we're finding is that most Americans have actually glyphosate circulating throughout their body every day. So a lot of the foods that are being consumed do have glyphosate present in them. The question is, at what dose do you see that they're actually contributing to some sort of ailment and tying them to these specific types of diseases.
BRODIE: So obviously this, the answer to this will most likely be based on whatever your future research finds, but I'm wondering if you think that there's a possibility that depending on what you find going forward, might the EPA need to adjust what is considered a safe level of glyphosate, or maybe this is something that is done away with altogether?
VELAZQUEZ: Yeah, I think that, you know, that the, once again, as you mentioned and as I mentioned earlier, more research is needed to identify the dosages at which these effects are occurring. It's very hard for me to say now whether our results will show that whether glyphosate should be eliminated entirely or whether dosages need to be reconsidered, but I think more research is needed in that area before such conclusions can be made.
But I think the important point to note here is that we are finding that there are some effects to the brain, which we didn't know about, you know, in the last decade or so. So that's why more research is, is critically important in this area.
