In this episode we discuss:
- Why Parkinson’s disease is increasing
- Genes vs. environment
- The toxins linked to Parkinson’s
- The evidence for causation
- Why exposure can be difficult to recognize
- What you can do to reduce exposure
- What happens after diagnosis
- The future of prevention
Show notes:
Hey everybody, Chris Kresser here. Welcome to another episode of Revolution Health Radio. This week, I’m really excited to welcome Dr. Ray Dorsey as my guest. He’s a neurologist working to end Parkinson’s disease by addressing its root causes, which are primarily toxic environmental exposures.
So this is a topic I’ve covered a few times on the podcast in the past. I’ve written blog posts about it. I have a personal stake in this. I have a couple of extended family members that are suffering from Parkinson’s disease and that have confirmed environmental toxin exposure. One person grew up in an agricultural community close to a lot of farms that were using pesticides, and one person lived in an area with pretty extreme air pollution. So I’ve been aware of this connection for some time. But Dr. Ray Dorsey has really done some pioneering work in further quantifying and qualifying this relationship and kind of laying it all out in his recent book, which we’ll talk about. But it was a fascinating conversation.
We covered extensive evidence linking Parkinson’s disease to environmental toxin exposure, what the most important toxins are to be aware of, and how to reduce your exposure to them, and what to do if you’ve already been exposed. So it was a fascinating conversation. I hope it’s really going to move this forward in the public consciousness because there’s not enough awareness about it, both in terms of the mainstream medical establishment and also just the general public. So hopefully this podcast will play some small role in increasing that awareness. All right, without further ado, let’s dive in.
Chris Kresser: Dr. Ray Dorsey, welcome to the show. It’s a pleasure to have you.
Ray Dorsey: Thank you very much for having me, Chris.
Chris Kresser: So I’d love to start with just what was your ‘a-ha’ moment? When did this awareness that the way we conventionally view Parkinson’s disease may not be complete, and that there’s this other major factor come into sharp view for you?
Ray Dorsey: 2017. So in 1817, Dr. James Parkinson described a disease, a new disease, that he said had not been classified in the medical literature. On the streets of London, he saw six people, largely older men, with a tremor, astute posture, this tendency to walk forward faster and faster, and to fall forward. And he said this disease hadn’t been classified in the medical literature. He was 61 years old at the time and wrote a really lengthy essay on the disease that he called Paralysis Agitans. A French neurologist later named it after him. 200 years later, in 2017, I was with my friend Dr. Bas Bloem and at a symposium celebrating the bicentennial of Dr. Parkinson’s description of the disease, and it was estimated at that time that 6 million people had the disease. So, how did you go from a disease that affected six people in London that wasn’t even in the medical textbooks to the world’s fastest growing disease affecting 6 million?
And it bothered my colleague, Dr. Bloem, my two other friends, Doctors Todd Sherer and Michael Okun, and me, and I went to Google Scholar, and I said, well, the person who’s done a lot of work on this is a woman named Dr. Caroline Tanner. She’s a neurologist like me, but she has a PhD in epidemiology. And for 40 years she’s quietly, diligently been telling us that the principal causes of Parkinson’s disease are not inside of us. Only 13 percent of Americans carry a genetic cause or genetic risk factor for the disease. The principal cause of disease is not in our DNA, it’s outside of us in our environment. And she’s, in my mind she’s a giant, but in real life, she’s maybe five feet tall, and she looks like a grandma. She’s like the most unassuming person in the entire world, and she’s told us for 40 years that chemicals like pesticide called paraquat, other pesticides, dry cleaning and degreasing chemicals, if you can believe it, and outdoor air pollution are all fueling the rises of this disease.
And her work’s been read, but people just haven’t incorporated it and they haven’t internalized it because we haven’t, and Parkinson’s continues to rise. 250 people are diagnosed with the disease today. 100 Americans alone will die with the disease today. If we listen to the words and the work of Dr. Caroline Tanner for the last 40 years, we would realize that this disease is driven by environmental chemicals, and as such, this disease is preventable.
Chris Kresser: So I just want to play devil’s advocate here, just to make this more clear for people. What is the strongest evidence that the rise is not just aging, longer survival or better diagnostic methods?
Ray Dorsey: Yeah, so this is what my colleagues think. If we’re aging, well, let’s just go back in 1800. So 1800 London, there’s over a million people there, and there are about 100,000 people, 50 to 100,000 people over age 60 in 1800 London. Today, about 1 percent of Londoners over age 60 have Parkinson’s disease. If that were true, when Dr. Parkinson described the disease, there would be a thousand people with Parkinson’s disease. He described six. So either the docs really missed it, or it was really something new.
Even in Roman times, 5 percent of the population was over age 60. No cases of Parkinson disease. If you go back to 2400 years ago, I forgot which psalm it is. It says that the lives of humans are three score and 10, with strength fourscore, suggesting that even 2400 years ago in the time of Moses, that people were living to 70 or 80. If you want more contemporary things, if you look at the average age of the first 10 U.S. presidents when they died, George Washington, John Adams, it was 78. John Adams, age 90, writing letters to Thomas Jefferson, age 83, in 1826. Neither of them has Parkinson’s disease, neither has Alzheimer’s disease. None of the early presidents had either disease. If you look at the average age of death for the last 10 U.S. presidents who died, it’s also 78, and numerous of these individuals have had neurological diseases, like Ronald Reagan with Alzheimer’s and President George H. W. Bush with a Parkinsonian disorder. If you want to look in the lab, you put a laboratory animal in the lab and you let it age, it will never spontaneously develop Parkinson’s disease. A laboratory animal left to age will never spontaneously develop Parkinson’s disease. The only way that laboratory animal, a mouse, for example, develops Parkinson’s is if you manipulate its genes or expose it to toxic chemicals. Sometimes you have to do both. And it’s growing far faster than any other age-related disease. It’s growing far faster than aging alone could explain. So there’s a wide range of evidence that it’s not just aging. The second thing is that lots of people like to say, “Well, we’re getting better at diagnosing the disease.” If that were true, we’re getting better at diagnosing just about every disease, and so it would be really hard to say why is Parkinson’s growing a lot faster than other diseases? Are we selectively better at diagnosing Parkinson disease? I think we should stop patting ourselves on the back and start rolling up our sleeves. If we look at this a little bit more carefully, there are diseases that we are unquestionably better at diagnosing. Multiple sclerosis, for example. MRI has revolutionized our ability to identify people with multiple sclerosis that we previously dismissed. Some of them we dismiss as hysterical, and the rates of muscle sclerosis are relatively constant.
Stroke, as many of your listeners know, is much better diagnosed today with MRI. Even in my time, we would miss strokes that would be picked up by MRI. But the number of new cases for stroke in the United States, adjusted for age, is down 30 percent. So other diseases for which we are unquestionably better at diagnosing are either flat or down, and Parkinson’s disease is up. So we are either selectively better at diagnosing Parkinson’s disease, even though we really rely on clinical examination, or that this disease is just more rapidly rising. I’d also say that the error to be made here is not to underestimate the rise and not to downplay the concern. But worst case, we’ve taken action to address the disease that might be rising because of our increased awareness. But I just don’t think that’s the case.
Chris Kresser: Yeah, well, you’ve made some pretty strong arguments in favor of the fact that this is rising, and to be clear, I’m very sympathetic to that view, and I think it’s probably correct. We see that in not just Parkinson’s, but lots of other diseases that are environmentally mediated or mediated by the exposome if we were to look at that larger category of epigenetic and environmental inputs. So maybe that’s a good segue to talk a little bit more about the relationship between genetics and environmental factors here. You said earlier, 13 percent of people carry genes that predispose them. So, if we use the, if the phrase genes load the gun, environment pulls the trigger, is that even true for Parkinson’s? Because if it’s only 13 percent that carry the genes, it sounds entirely possible to develop the condition, even if you don’t have genetic susceptibility. But what role does genetic susceptibility play in this condition?
Ray Dorsey: So not only is it entirely possible that you can do it, but the vast majority of Americans, 87 percent of Americans, have no known genetic cause or genetic risk factor. So that either means that my outstanding colleagues in genetics have missed it. I don’t think they have, Dr. Andy Singleton’s a world-class geneticist, or that there just really aren’t strong genetic underpinnings to the disease, and that’s indeed the case. Behind me, one second here. Behind me is the Bible of Neurology, written by Sir William Gowers.
Chris Kresser: It’s a hefty tome.
Ray Dorsey: That’s a hefty tome. It was written in 1884, and Dr. William Gowers described Parkinson’s disease in it. And I’ll read you one sentence from it. This is what he wrote in 1884. He said, “Heredity can seldom be traced, perhaps in not more than 15 percent.”
Chris Kresser: Wow.
Ray Dorsey: So, Sir William Gowers, the father, writes the bible of modern neurology in 1884, and he tells us that less than 15 percent of people have a family history of the disease. Research in 2024, published in Brain, two studies, both came to the same conclusion, less than 15 percent of people in the United States, in Latin America, in Europe, in the Middle East, basically in every part of the world that’s been examined, carry a genetic cause or genetic risk factor for the disease.
Now that doesn’t mean that genes aren’t important, and genes might help us explain why some people exposed to these chemicals are more likely to develop the disease than others. So the most common genetic risk factor for Parkinson’s disease is a mutation in a gene called GBA1 or GBA. And research done by Dr. Caroline Tanner, again, she’s very busy, showed that people who have that genetic mutation and are exposed to paraquat pesticides have a heightened risk of developing the disease. There’s also research that you and I differ in our breakdown of medications. You might break down a medication really well, I might be a little bit slower. It turns out that there are genetic differences in the way we break down pesticides, and some of us who are better at breaking down the pesticides might be less prone to its toxic effects than some of us who aren’t. But I think we need to look at Parkinson’s disease like we look at lung cancer. I think most of your listeners realize that lung cancer is largely driven by smoking, at 80 percent. Even today, 80 percent of lung cancer in the United States is due to cigarette smoking. If you don’t smoke, you largely don’t get lung cancer. There are exceptions. There’s radon, asbestos, or other secondhand smoke. But largely speaking, if you don’t smoke, you don’t get lung cancer.
I don’t think if you don’t get exposed to pesticides, if you don’t expose to heavy metals, if you don’t get exposed to dry cleaning degreasing chemicals, if you don’t get exposed to air pollution, you’re largely just not going to get Parkinson disease. And so genes play a small role in disease and might explain why some people are more susceptible to it. But again, the vast majority of people with Parkinson’s disease in the United States and every part of the world that’s been examined get the disease with no genetic predisposition.
Chris Kresser: Okay, I think you just addressed this, but I want to double-click on it because it was my next question, which is, so we’ve established that Parkinson’s is on the rise, that genes play some role but fairly minor in the condition, and environmental factors are are the trigger. Is it the case that pesticides, solvents, and air pollution comprise the vast majority of the impact of environmental factors? Or are there other environmental factors as well that make a significant contribution?
Ray Dorsey: Yeah. So this is a great question. Their list of environmental factors that are linked to Parkinson’s disease is long. They vary by time. Like what time period are we talking? Are we talking 1817 when there weren’t synthetic pesticides, there weren’t industrial solvents? There we had high levels of air pollution. Air quality in 1800 London is equivalent to what Chicago experienced when the Canadian wildfires came down this summer and gave Chicago the worst air quality in the world. That was every day 1800 London, and London also had high levels of metals like from burning of coal. So I think either exposure to metals and/or air pollution, or perhaps both, were principal causes of disease in 1800 London. If you have some listeners in the Central Valley of California, there’s a weed killer called paraquat that’s widely sprayed on fields of corn, soybeans, I don’t know if cotton, I don’t think cotton’s grown there, and vineyards, and that could be why they developed it. If you were a Marine or served at Camp Lejeune in the 1970s, a military base in Wilmington, North Carolina, on the Atlantic coast, you were exposed to trichloroethylene and perchloroethylene. These are two widely used dry cleaning and degreasing chemicals. Very simple structures, six atoms each, that have contaminated up to 30 percent of groundwater in the United States.
So I think the causes vary a lot by time. When are we talking about? Are we talking about 100 years ago, 200 years ago, before some of these chemicals existed. Are we talking about 100 years ago when other chemicals, or 50 years ago like PCBs used in the electronics industry, DDT, and other classes of organochlorine pesticides might be contributing to the disease? Or are we talking about today? There is a common theme to these chemicals. All these chemicals largely damage the energy-producing parts of our cells. Your listeners know that the engines of our cells are mitochondria. They convert glucose into energy. Your brain’s only 2 percent of your body weight, but 20 percent of your energy consumption. It is a sugar-consuming machine, and nerve cells are chock full of mitochondria, especially the nerve cells that die in Parkinson’s disease. Some of them, if you stretch them out, are four meters in length, twice my height. I’m a really tall guy. They’re not insulated. They’re not wrapped in myelin. They have huge energy demands. One of my colleagues says, “Ray, imagine them as a big garbage bag filled with jelly beans, and these jelly beans are mitochondria.” So all these chemicals damage the mitochondria. They’re all either inhaled, like paraquat being sprayed on farms, or ingested like the drinking water at Camp Lejeune, contaminated with trichloroethylene, and they all generally are fat loving, which allows them to cross membranes, including the gut and including membranes in our nose, including the placenta even. And so they readily can enter our body. So if you have a fat-loving chemical that damages the mitochondria that we either inhale or ingest, I think you have a setup for a risk factor for Parkinson’s disease.
Chris Kresser: That’s really helpful. But all of these things we’re talking about fall under the umbrella of environmental chemicals in some fashion, right?
Ray Dorsey: Oh yeah.
What if Parkinson’s disease isn’t simply an inevitable consequence of aging—but is partly preventable? Neurologist Dr. Ray Dorsey joins Chris Kresser to explore the growing evidence connecting Parkinson’s to pesticides, industrial solvents, air pollution, and heavy metals. #ChrisKresser #Parkinsons
Chris Kresser: And so my question, just to be more specific, some neurological conditions have perhaps antibiotic exposure as a risk factor because that disrupts the gut flora and then triggers. Others have cigarette smoking. You mentioned cancer. Others have, lack of physical activity or poor diet or whatever. So, do we know at this point, is it true that the lion’s share of the environmental exposure is chemicals, and those other factors may play some small role, but it’s nothing compared to chemicals?
Ray Dorsey: Yeah, I think that’s exactly right. Parkinson’s disease is largely a man-made disease. Yes, some of your listeners will notice that some people got Parkinson’s disease or something like Parkinson’s from influenza pandemic or sleeping sickness in 1918. Any of your people have seen the movie Awakenings. These are individuals who got a Parkinsonian disorder 1919-1920 that got infection, likely from influenza, that got a Parkinsonian disorder and Robin Williams in the movie plays Oliver Sacks and he gives him a little bit of levodopa which led to an awakening, a temporary awakening for these individuals.
There’s some research that suggests influenza virus today might modestly increase the risk of the disease. There are other viruses that can do it, and there are also medications, antipsychotic medications, that can reproduce the features of Parkinson’s. We don’t call it Parkinson’s disease, we call it medication-induced Parkinsonism. But by and large, the vast majority of people who have Parkinson’s disease have it because they’ve been exposed to environmental chemicals. And in our environment, we get rid of these chemicals, we get rid of Parkinson’s disease.
Chris Kresser: Okay, great. So, next question is from an epidemiological perspective, I would assume you can draw pretty strong correlations between particular geographic areas where the concentration of these chemicals is known to be high, and the incidence of Parkinson’s in those areas. And one of the challenges with epidemiology is proving causation, right? Because we have correlation, but if there are things like the Hill criteria which can strengthen the likelihood that correlation does equal causation when enough of those variables are in place. So, what do we know? What can we say about the epidemiology and the causal chain here?
Ray Dorsey: So, first of all, the first man, the first interview who’s brought up the Bradford Hill criteria, we’re giving it, we’re going to give it, we’re going to send you a couple extra books to give to your listeners for free because you brought it up. So let’s first talk about the mapping. So if Parkinson’s disease were purely due to aging and purely due to genetics, you would imagine that a map of the world adjusted for aging and genetics would have a uniform rate of Parkinson’s disease. But the map of the world doesn’t look like that. Quite frankly, the map of the United States doesn’t look like that. The map of the world shows that countries that are most industrialized, like the United States and Canada, have five times the prevalence of Parkinson’s disease as less industrialized parts of the world, like sub-Saharan Africa. Other diseases don’t look like that. Other diseases like stroke show it’s higher in sub-Saharan Africa than it is in the United States.
Even within the United States, you see a two to threefold variation in the rates of Parkinson’s. In 1987, André Barbeau was a Canadian neurologist, and he was really concerned about pesticides being sprayed in the rural parts of Canada, and he quantified the amount of pesticide used in rural parts of Canada, ranked order of these different provinces in terms of the amount of pesticides that they had, and ranked order in terms of the amount of Parkinson’s that they had, and wanted to see what the degree of correlation was. Something that’s perfectly correlated, like I don’t know if anything is perfectly correlated, but the amount you study for a test and how well you do on the test that would be one. If something’s no relationship at all, it’s zero. In this case, he found the correlation between pesticide use and Parkinson’s disease was .967.
Chris Kresser: Wow. And just for the listeners, that’s probably one of the strongest correlations that I’m aware of in medicine and even epidemiology. There are far lower correlations between, for example, dietary factors and morbidity and mortality.
Ray Dorsey: And that work has been replicated in France. My friend Dr. Alexis Elbaz has shown that if rank order different cantons in the south of France, where the vineyards are, and the amount of pesticide use and the amount of Parkinson’s, again near perfect correlation. Israel, I think some of the same study, and I’ve seen it in Mexico. So there are strong, strong, strong studies indicating this. Really begging you to come up with an alternative explanation for this relationship. And mind you, that many of these pesticides in the lab reproduce the features of Parkinson’s disease in laboratory animals when they’re exposed to it. Their paws shake, they move around less, and you look at their brains under the microscope when they have fewer dopamine producing nerve cells.
Chris Kresser: Let’s touch on a few of those Bradford Hill criteria, and for the listeners, these are criteria established by a scientist named Bradford Hill, which were designed to determine the likelihood that a correlation was likely to be a causal factor. So, in other words, if more of these criteria are true.
Ray Dorsey: So you’re getting me, get to get all my books. So a shout out to Bradford Hill, who, with Richard Doll, an internist in England, showed that doctors who smoked, had a 30 to 40 times increased risk of dying of lung cancer compared to doctors who didn’t smoke. And then he himself was like, “Well, I’ve shown an association between smoking and lung cancer. How do I know that this is causation? Maybe all smokers like to drink coffee, and it’s coffee that’s causing the lung cancer and not cigarettes.” So he put together a criteria called the Bradford Hill criteria to let you know when you could go from association to causation, and he put together nine of them. And I’m going to have to consult my book to see if I can get all nine of them.
Chris Kresser: While you’re doing that, I’d love to ask you about two of them, which are, one is the dose-response relationship. So if a causative relationship was expected, we would expect that as the dose of the particular compound increases, then the impact or the effect size might increase as well. And then another is what you, I think, already touched on was whether the relationship is monotonic. Meaning does it continually increase as the exposure increases?
Ray Dorsey: Yeah. So dose-response. So, the more cigarettes you smoke, the greater your risk of lung cancer. So, Dr. Caroline Tanner in 2011 showed that farmers who work with paraquat have 150 percent increased risk. Presumably, farmers have the greatest exposure. Her colleague, Dr. Beate Ritz at UCLA showed, I think in 2023 or 2024, that simply living or working near where paraquat is sprayed has 100 percent increased risk. So you get a little bit of a dose response relationship. Dr. Brittany Krzyzanowski and her colleague, Dr. Rodolfo Savica, a neurologist at the Mayo Clinic, showed that living near a golf course is associated with an increased risk of developing Parkinson’s disease. So the closer you live, the higher the risk. As you moved away, the risk mitigated.
So we have evidence for this. The challenge is that, one, people who smoke cigarettes know that they smoke. Farmers, who may or may not know what pesticides that are being used, especially if you’re a farm hand. If you’re living near a golf course, you have no idea, generally speaking, what pesticides you’re being exposed to. If you’re a Marine at Camp Lejeune in the 1970s, drinking the water, the last thing you’re thinking about is the amount of trichloroethylene that’s in it. So we don’t really know, people don’t know when they’re exposed, and they can’t really quantify it. So we ask people, do you smoke one pack per day, two packs per day? And people generally know how much cigarettes they do. So we don’t know that. So even though we have that very imperfect information, and in many cases, people don’t even know that they’re being exposed, all these things would bias you to not finding a relationship, to being unable to find one. So when you do find these relationships, you need to really sit up and pay attention. Some of the other Bradford Hill criteria are, one, did the exposure happen before the disease? Did you smoke the cigarettes and then develop lung cancer? Were you exposed to the chemical and then developed the disease? Is this biologically plausible? Is a chemical that damages the mitochondria and is fat soluble and is inhaled or ingested, does that make sense that this could give rise to Parkinson’s disease? I think the answer is that, are the results consistent with one another? Have numerous different investigators, as I told you, the Canadian neurologist, the French neurologist, the Israeli neurologist, and the Mexican neurologist all replicating the same study and coming to the same conclusion? Are there laboratory studies to support the diagnosis?
And so, my colleague Dr. Alastair Noyce and his colleagues published a recent review, and they highlight that paraquat, this weed killer tied to Parkinson’s disease, that over 70 countries including China have banned, but the United States has not, has largely met just about all the different Bradford Hill criteria, allowing you to reach, I think, a conclusion that paraquat causes Parkinson’s.
Chris Kresser: Okay, I know we spent a lot of time on that, but I really wanted to dive deep because I have found, and I’m sure you’re more aware of this than anyone, that people often don’t take this as seriously as they should, and that’s maybe in part because it’s not really, as you pointed out, it’s very clear in the research literature, but that awareness has not percolated down into the mainstream consciousness. Whether you’re talking about your average primary care doctor or you’re talking about just the public perception of what drives Parkinson’s. So I wanted to really set the stage here for the next part of the discussion, which is, okay Dr. Dorsey, I think we’ve made a strong case that Parkinson’s is a man-made disease caused by environmental toxins. Now, the two biggest questions that are going to be on the listeners’ minds are going to be how do I know if I’m exposed, and therefore how can I reduce my risk? What are the biggest drivers? Is there an 80/20 rule here? Before I excavate my entire life, what are the biggest drivers that are going to give me the biggest bang for my buck in terms of identifying exposure?
Ray Dorsey: Yeah, so we got this question a lot. So on page 237 of our book, we give you the Parkinson’s 25. So what are 25 actions you can take in your everyday life to reduce your risk of getting Parkinson’s? Or if you’re among the million Americans with the disease, what are actions you can take to slow your progression? Just like if you are a smoker and you get diagnosed with lung cancer, the doctor is going to tell you to stop smoking cigarettes because smoking increases your rate of progression. If you’re diagnosed with high blood pressure, the doctor is going to hopefully tell you to decrease your salt intake because salt intake is associated with greater progression. Yet, Dr. Beate Ritz has shown that ongoing pesticide exposure, even for people who already have the disease, is associated with an increased rate of progression.
So I think there are three major areas people can focus on: what do you eat, what do you drink, and what do you breathe. What do you eat? If they’ve been reading your work, they’re going to get a paleo diet that preceded the use of pesticides. Many pesticides are designed to damage the nervous system of insects, for example, that’s how they work. Perhaps not surprisingly, if you design chemicals to damage the nervous system of insects, they might have unfavorable effects on the nervous system of humans. So, buying organic, washing your fruits and vegetables. Also, and you probably know this as well, is that when you eat a cow, like whether it’s cheese or milk or meat, you’re not just eating the cow, but you’re eating what the cow ate. And the cow, if it eats a fat-loving pesticide, it concentrates that pesticide because it can’t pee it out. It doesn’t dissolve in water. It concentrates it in its milk and in its fat. So when you’re eating a cow, you’re getting potentially even higher levels of exposure. So if you like dairy, like I like cheese and yogurt, buy organic. And if you like meat, buy organic. That might even be more important than what fruits and vegetables. I recommend both, but that’s a big one.
On the water front, if you’re among the 40 million Americans who drink water from a well, please stop at the grocery store on your way home, and either get a pitcher that has little filter in it, a carbon filter, or get a water filter that you can attach to your faucet. So they’re 30 bucks, 20 bucks, would be the best thing you’ve ever bought if you have well water, because well water in the United States is not regulated by the Safe Drinking Water Act, and that means it’s infrequently tested. And when it’s tested, it’s usually just tested for bacteria so you don’t get diarrhea, but not tested for pesticides or other chemicals. And wells tend to be in rural areas, tend to be near farms, and farms tend to use pesticides, and those pesticides can contaminate the groundwater. And so, you, your children, your spouse can be drinking for years pesticide-laden water that sets you up decades later to develop Parkinson’s disease. So if you drink water from a well, get a carbon filter or stop at the grocery store and get a pitcher and do it. I am told that Costco, I make no endorsements, I’m told Costco has some great products as well. And then the third one is air. And so I recently moved to New York City, as you can see outside my window, I got a great view of a brick wall. And I was really concerned moving to New York City from Rochester, New York, about air pollution. So I did a deep dive on air quality in New York City. If anyone’s seen a movie in the 1960s or 70s or 80s in New York City, the sky is not blue. The sky is brown or gray. Air quality in New York City is much better than it used to be. Surge pricing has made air quality, at least in Manhattan, a lot better than it once was. If you live in a part of the country that does not have good air quality, buy an air purifier for your home or your workplace, or perhaps both. I have one in my bedroom. We have one in our bedroom and one in our living room. And you can get a little monitor to measure air quality.
We all have a measure of the temperature of the air inside of our rooms or inside of our homes. From a health standpoint, more important than the temperature is likely the amount of particulate matter or PM2.5. These really small pieces of dirt and soot, like one-thirtieth the width of our hair, that are small enough to penetrate our nerves, responsible for smell. And hitchhiking on those little pieces of dirt and soot are often toxic metals. Lead from gasoline, iron from brakes, platinum from catalytic converters. So if you live in a heavily polluted part of the country, get an air purifier. When you drive in traffic, roll up your windows, hit the recycling air button on your dashboard. And I guess the final thing I’ll say is don’t poison yourself. If pesticides are causing Parkinson’s disease or contributing to it, you don’t want to be spraying a lot of pesticides in your home or your yard.
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Chris Kresser: Yeah, that makes a lot of sense. I’m a big believer in indoor air quality as a huge driver of health. We spend a lot of time indoors, and the quality of air indoors is often worse than it is outdoors in many locations. And there was actually just a study published a couple weeks ago establishing a correlation between indoor air quality and cognitive function. And they showed that even using an air filter, a relatively short period of time, led to a significant improvement in cognitive function. So it’s a pretty affordable and simple lever to pull to be able to improve our health.
Ray Dorsey: Yeah, and if you care about, I care a lot about Parkinson’s disease, but if you really care about Alzheimer’s disease, it’s probably even more important. Air pollution is probably even a larger risk factor. Probably just an immense risk factor for Alzheimer’s disease. So breathe clean air.
Chris Kresser: So let’s break this down. So we’re talking about prevention. You also mentioned that this can even help if someone has already been diagnosed with Alzheimer’s. Do we know much at this point about the impact of, let’s say, detoxification? So we know that chemical exposure can accumulate over time in our fat tissues, primarily. You mentioned that in the context of beef and why it’s so important to eat grass-fed and organic ruminants because they tend to store and accumulate those toxins in their fat tissue. So the same is true, I assume, in humans, such that exposure from 20, 30 years ago can accumulate and then trigger Parkinson’s at some point.
What I’m getting at here is, what is the relative importance of removing yourself from exposure if you still have it? But let’s say you’re aware of all this stuff. You’re living a pretty clean life. You don’t have any further exposure. Maybe you had it when you were a kid, or for many decades, now you don’t have exposure, but you still have Parkinson’s. Is there anything to be done through this lens at that point? Or is that sort of, I don’t mean this in a glib way, but like that ship has already sailed and that exposure has already done the work that it unfortunately did, and there’s not much that you can do about it at that point?
Ray Dorsey: Yeah, the short answer is, I don’t know. If you asked me a few years ago, I would have said the ship sailed. Now I’m a little bit less certain that the ship has sailed. I think at a minimum we need to stop fueling the fire. So Parkinson’s disease, Alzheimer’s disease, ALS are all due to protein misfolding, perhaps triggered by these environmental chemicals or their effects on the mitochondria. Just like with lung cancer, you want to stop smoking cigarettes because you don’t want any more mutations to be accruing for the cancer that you already have. And I think for Parkinson’s disease, for Alzheimer’s disease, for ALS, you want to stop whatever fire led to the misfolding of this protein and the pathology to begin. You want to take that fire out. Because your brain, your body is trying to combat this misfolded protein. It’s battling really, really, really, really hard to prevent these nerve cells from dying off. And you want to give them as much of an opportunity, your body as much of an opportunity to win that battle as possible. And so the number one thing is to stop the exposures.
Now the question is, what can you do if you’ve already stopped the exposures? Can you do something to undo the damage? In the neurology world, the word chelation is used in the same breath as like frontal lobotomy. It’s like voodoo. Even though there are clearly conditions for which chelation, like Wilson’s disease, works, and it’s demonstrated to be the most effective treatment. So I’ve been looking at ALS, and it turns out ALS, Lou Gehrig’s disease, the same environmental risk factors that are tied to Parkinson’s disease, are tied to ALS. Parkinson’s disease was described in 1817 in London by Dr. James Parkinson. The first major description of ALS is 1874 by a French neurologist, Jean-Martin Charcot. Less than 15 percent of people with Parkinson’s disease can carry a genetic cause or genetic risk factor for disease. Less than 15 percent of people with ALS carry a genetic cause or genetic risk factor for disease. Pesticides, solvents, air pollution, and metals are linked to Parkinson’s. They’re linked to ALS as well.
In 1974, the king of neurology is a neurologist named Dr. Lewis Bud Rowland. He was so good as a neurologist. He was not only the chair of the neurology department at the University of Pennsylvania, the oldest medical school in the country, he became the chair of the neurology department of Columbia University, widely viewed as one of the top neurology departments in the country, especially when he was chair. He was the editor of the major Neurology journal. In 1974, he described a patient that he was caring for at the University of Pennsylvania, where I trained, who had ALS, and he said that, “Hmm, this person with ALS really has ALS because of lead exposure.” He had worked with lead batteries for 30 years, and he gave him a drug called penicillamine, which removes the lead from the individual. So this person already had ALS due to lead exposure, and he gave him a drug called penicillamine, and his symptoms got better. I was like, I didn’t get taught that. And so he showed pictures. He had a wrist drop where his hands were down like this, and his wrist went to this, and he could throw darts again. And I did a deeper dive, and I looked, and there are numerous case reports for the last 100 years of people getting better who got ALS due to exposure to metals, and they got medications to remove the metal from them. Some of them got better, some did not. Not everyone did, but some clearly did. I think one was back to able to climb up, I think climb up upstairs and carry her baby. I think it might have been a woman who benefited in that case. Those studies largely haven’t been done, at least to my knowledge, in Parkinson’s disease. But if we want to cure a disease, I mean, this is like Functional Medicine 101, the first step to curing a disease is to know what its cause is. And I think for too long we’ve been told that Parkinson’s disease is, and I was taught this, that was largely due to aging, genetics, and bad luck. And I think that’s largely untrue. And I think Parkinson’s disease is largely due to pesticides, solvents, air pollution, and metals, and there are other chemicals too. And if we start focusing on what we can do to undo those effects of those treatments, whether it’s giving a drug to remove the metals, again, not been shown to be beneficial in Parkinson’s disease, but largely not been studied, then I think we get a lot closer to the treatments.
The prerequisite to curing a disease is to know what its cause is, whether that’s a stomach ulcer or pneumonia, and I think we can figure out that the cause of these diseases, not just for Parkinson’s, but for ALS, but for Alzheimer’s disease, dementia, Lewy bodies, perhaps even intellectual disabilities, perhaps even some cases of autism, are nerve toxins in our environment. We can get those out, and then we can start studying the effects of medications to undo the damage that these chemicals have caused.
Chris Kresser: That’s great, and I’ll share a little bit of my functional medicine perspective and experience on this topic, just for the listeners. And the caveat here is obviously this is just my clinical experience. This has not been studied, as you pointed out, Dr. Dorsey. We don’t have large, randomized controlled trials here to guide us. But I think there are some interesting lines of research. So, when I got into functional medicine, I heard a lot about detox. I’m a skeptic by nature, so I wanted to go and see what the research actually showed about detox and detox protocols. And it’s not very robust. There’s a lot more research that needs to be done, but there are some interesting signals.
For example, heavy metals have been detected in sweat, and other toxins have been detected in sweat, and there are some small studies that show that sauna use or even exposure to really hot water that induces sweating can potentially release some toxins. How much, how significant is that? We don’t really know, but the way I tend to look at these things is like, is there potential upside, and what is the potential downside. With a drug that chelates, I think there’s some pretty significant potential downsides and risks that we’re already aware of. And so you would have to have very strong evidence of benefit to be willing to justify that risk, at least the way that I think about it. But with sauna use and sweating from hot water, the risk is relatively low as far as we know. And if there is some potential benefit, I was comfortable recommending that to my patients, and I saw even in patients with early stage tremor, Parkinson’s, and other conditions, I would sometimes see improvement. Sometimes not, but sometimes I would. And I also had a similar experience with binders like modified citrus pectin and charcoal, which have been shown to help with some toxin excretion too.
So, I think it’s hard to say anything with any kind of conclusivity here, but I hope there is more work and research done in this area now that this really strong causal link has been established.
Ray Dorsey: Let me, I’m going to push even further. If these chemicals are causing these diseases, why aren’t we measuring these chemicals in people’s bodies?
Chris Kresser: Yeah.
Ray Dorsey: I’ve recently joined a new organization called Atria Health and Research Institute in New York City. Small little plug. They’re trying to move healthcare from reactive sick care to proactive preventive care. And until six months ago, maybe a year ago, I had never ordered a pesticide level on somebody. Even though pesticides, I told you, many are designed to damage the nervous system of insects. It’s almost certain that I have seen lots of people, almost every neurologist has seen patients who have had untoward consequences from exposure to pesticides. But we never measure. We never measured trichloroethylene, this widely used degreasing and dry cleaning chemical. There was a study done in Italy, I think, in the 1990s that found this chemical or its metabolites in the urine of three quarters of the general population in Italy, I think in men. Why aren’t we measuring these chemicals? If we measure them, can’t we then tell people, “Hey, are you getting exposed to this? And can we stop this exposure so we can reduce your risk of not just getting Parkinson’s disease, but trichloroethylene is known to cause cancer. What a wonderful way to prevent cancer.” This would be screening people for carcinogens.
More generally, isn’t it kind of crazy that when you get diagnosed with cancer, that we don’t measure known carcinogens in you? I mean, the list of cancer-causing chemicals is long and it’s large, it’s long and it’s known. I mean, vinyl chloride, benzene, arsenic, lots of these things are known to cause cancer. Why aren’t we measuring it? Why, if I’m at risk for cancer, why am I not being screened for these chemicals? Why, if I’ve already had one cancer, am I not being screened for these chemicals? I think we in medicine need to stop, pump the brakes a little bit, and recognize that we are not doing a very good job at preventing diseases. And if you need evidence of that, we spend 1 in every 5 dollars in the wealthiest nation in the world on sick care. We should be taking action to identify what the root causes of these diseases are. In many cases, for rare diseases, in many cases it’s genetics. But for common diseases, in most cases it’s not. In most cases, it’s due to chemicals in our environment or behaviors that some of us know about. And these chemicals, we can take action to measure them. We can take actions to mitigate them. We can create a world largely free of ALS. We can create a world largely free of Parkinson’s disease. We can create a world largely free of Alzheimer’s disease. Indeed, for the vast majority of human history, we’ve had a world largely free of Parkinson’s disease, largely free of ALS, and largely free of Alzheimer’s disease. These diseases have all been described in the last two centuries. All after the Industrial Revolution. All in an industrializing nation. And all are tied to industrial pollutants.
The clues are all around us. We need to look at the world a little bit differently. Open our eyes. And if you see what I have seen, I think you’ll realize that we can create a world where these diseases are just largely preventable, and that we can live a life where we’re not worried about getting Alzheimer’s at 85, or Parkinson’s at 65, or ALS at 50.
Chris Kresser: Well, Dr. Dorsey, that’s a perfect place to conclude. I couldn’t agree more. In fact, my second book on this was entirely about this topic, Unconventional Medicine, talking about how we need to move from disease management to true healthcare. And you articulated that better than I could have. So, thank you so much for this important work. Can you please tell everyone the name of your book, you held it up there, and where they can find it?
Ray Dorsey: The Parkinson’s Plan. You can find it on Amazon or your favorite place to get books, or the library, which is where I find my books. And I’ll be looking out for yours, Chris, at the library very soon. If you have any questions, you can email us at [email protected]. We’d love to hear your stories. And my colleague Dr. Michael Okun and I are working on our next book, which will be loosely titled Preventable Brain Diseases. How these chemicals in our environment are not fueling just the rise of Parkinson’s, but the rise of ALS, Alzheimer’s, and what role that they play in autism and intellectual disabilities. These things are all becoming increasingly common. They’re all happening on our watch, and they’re all happening, they’re all linked in some measure to chemicals in our environment, especially certain pesticides. Which, as I said, are designed to damage the nervous system of insects.
Chris Kresser: Well fantastic, Dr. Dorsey. Thank you again for your important work and for this conversation. I really enjoyed it.
Ray Dorsey: Thank you very much, Chris. Outstanding.
