Aliquot #132: Mitigating the Harms of Air Pollution

We can't always see the damage air pollution does, but it leaves a biological fingerprint on our lungs, our blood vessels, and even our brains. Fine particulate matter and chemical pollutants can erode the body's defenses, triggering inflammation, weakening the blood-brain barrier, and accelerating cognitive decline. These exposures are particularly concerning for people already at risk for neurodegenerative disease. But emerging research also points to ways we might minimize the harm. In this aliquot, Drs. Michael Snyder, Axel Montaigne, and I discuss precise monitoring, targeted nutrition, and environmental adjustments that may blunt the biological effects of the air we breathe.

In our first segment, Dr. Michael Snyder describes how his team uses wearable devices to collect detailed data on biological and chemical exposures, everything from pollen and fungi to pesticides, plastics, and industrial pollutants, collectively known as the exposome. These measurements offer a new way to investigate how specific airborne compounds contribute to health problems like autoimmune disease, allergies, and even early puberty. The goal is to finally connect the dots between environment and disease by identifying which exposures are most harmful and which ones we can control. To kind of shift gears for a minute and talk a little bit about some of your other data, which I found really interesting, and this had to do with the exposome. Am I saying that correctly? Yeah. Exposome.

The exposome. I'm not sure people know what that is. So, maybe you could kind of start there just explaining what that is. Yeah. Your exposome is all the things you're exposed to. And, what we're measuring is your airborne exposure. So, we have a device. This is the second generation. A third one's coming that's smaller. What it's doing is it's sucking up air at about 1/5 of what you breathe. And, what we have, it's measuring things like PM2.5 and temperature and humidity, but the power of this is it actually has a filter under the intake valve that captures all the particulates like pollen and bacteria and fungi that you're actually breathing. And, under that, we have a chemical absorbent that sucks up all the chemicals that you would also be breathing. And then, we analyze them.

We don't analyze them in real time. We take it apart and take the cartridge out actually. We can measure all the biologicals, meaning pollen and bacteria and fungi that you're exposed to. And we can measure all the chemicals that you're exposed to too. Pesticides, turns out there are plastics everywhere, pesticides are everywhere, but their amounts will vary quite a bit. And certain carcinogens are everywhere too. And some locations will have a ton of this stuff and others generally not so much. So that's what we're trying to measure. And the ultimate goal is to try and understand how exposures will contribute to, you know, your disease. Because there's no question that your risk for disease, it depends upon genetics, but it also depends upon environment.

And we think this is— that's the one thing that's always been very poorly measured is the environmental exposure. So that's what we're actively working on now amongst other things. So to try and capture that information. It's also the other— it's also the one thing that's not as easy to control For example, you know, you can, you can make a decision about what you're going to have for breakfast, lunch, or dinner, or whether you're going to fast and not eat, or, you know, when you'll eat your food, or if you're going to exercise.

But the things you're breathing in, with the exception of, I guess, if you're, if you, if you live somewhere close to a, you know, busier street or a highway, for example, where there's likely to be more particulate matter and air pollution and benzene It's very difficult to control the air you're breathing in. And there's been so many studies that have been coming out over the last few years. And of course, these are observational studies. There's all sorts of potential confounding factors that come along with observational data. But I think there has just been a pretty, I think, clear picture that air pollution increases the risks for a variety of age-related diseases in addition to just, you know, respiratory disease, Alzheimer's disease, you know, for one.

I mean, this is even something that's been shown in children that live in, for example, Mexico City that have, you know, passed away. There's been some postmortem studies that have looked at amyloid plaques in their brain and it's just like, Looks like an old person's brain in a young child in a place where the air pollution and the air quality is so poor. So, have you guys been looking at maybe where people are living or if they have a HEPA filter or some kind of filter, whether or not that makes a difference? Yeah. So, great question. So, the answer is that I'll say to some extent what you're talking about is the more nonspecific stuff like pollution, smoking. We know those are harmful, no question. And so, we have looked at that.

We actually discovered it looks like for one group we were studying that speculated that actually there's some heavy metal mining upstream and they speculated there's a high incidence of autoimmune disease. They thought that that might be due to the mining. And, it actually does correlate that way. That is, people live along the river, we discovered actually— Interesting. are seen to have a much higher incidence of autoimmune disease. So, I suspect their hypothesis is correct. And so, smoking, yes. I mean, those are documented studies by a lot of people. Inner-city kids exposed to pollution have a lot of this. I'll back up a little bit though. I do think you can have a better control, at least some control over this in the sense that you mentioned HEPA filter. Sure, that's good.

But, one of the things I discovered, I would argue we don't really know enough to make informed decisions about a lot of what's going on. And, as a good example, I used to have more severe allergies. They're kind of mild now. And, I always assumed they were pine. They came out April, May like everybody's. But then, when I actually did the correlation, when I looked at my data and I looked at allergies, something called eosinophils, which are involved in your allergic response, And, I correlated it with my exposures and guess what? It didn't correlate with pine, it correlated with eucalyptus. So, while you said, well, how's that actionable? Well, I got 2 trees behind my house, a pine and a eucalyptus. And, if I'm ever going to take one of them down, you can guess which one goes down first.

It's going to be that eucalyptus tree. So, I honestly think that having more information can sometimes lead to more informed decisions. And, I hope That'll be true about some of the other chemical things. There's just a ton we don't know. It's been speculated, why are girls reaching puberty earlier? And, it's been speculated that some of the plastics look similar to estrogen and nobody knows if that's true or not. How do you know? There's never been a proper study to do that sort of thing. We can make those measurements. We might be able to see if any of that's true. And so, I feel like we need a— everybody knows the environment is important for disease, but we don't know what aspects of the environment. Crohn's, you name a disease, Crohn's, you mentioned aging, absolutely true.

It's there and it's just never been measured. So, we don't know exactly which molecules are leading to these problems. Some of it may be just general particulates like pollution, air pollution, but some of it may be Very specific ones. And, let's see if we can get those things outlawed, right? Get those metals out of the gas was something that was— and now the paints was something, get lead out of paints was only because studies took a while to realize that lead was causing neurological problems. And so, you have to identify that, you have to measure it, you have to see it first to know what's going on. And, I think that's what the measurement's all about. Oh, we're just taking tons of measurements.

You're exposed to thousands of species, and which ones are associated with what aspects of your health, we don't know until we measure it. Have you guys measured down the exposome of firefighters, people that are fighting these wildfires? Yeah, believe it or not, we are. So, when these fires in California have burst out, we've been trying to get our monitors out to as many people as possible. And including firefighters. You have to put them a little carefully because they obviously can't interfere with their duties. But yeah, so we are trying to do this.

And I don't know what you know, but it's something you alluded to that kids in these poor areas like in Fresno where there's a lot of pollution, where there's a lot of firefighters, there's a lot of studies that show that they have a much, much higher incidence of allergies and asthma when they're in these areas. And it does seem to be associated with firefighters. So, we're trying to measure exactly what they're getting exposed to. And maybe there's some way to help control that or figure out ways to try and extract that. I guess we could see what the harmful elements are. Maybe even if we can't control the exposure, we'll try to as much as possible, I suppose. But maybe there's a way to try and chelate it and remove it out of folks. I don't know.

That's not exactly my area of expertise, but— I do know a little bit about not chelating, but so there's a couple of, not to get too far off topic, but you might find it interesting that So, one, there's a compound found in some cruciferous vegetables and particularly in broccoli sprouts, the young sprout of mature broccoli called sulforaphane, which has been shown in now quite a few studies. There's been intervention trials where people are specifically given sulforaphane concentrate and it causes— so, a lot of these Chinese studies have been done in China where there's also terrible air pollution problems. It increases the excretion of benzene, which is found in, you know, air pollution, cigarette smoke, for example, by like 60% after 24 hours.

Also, acrolein is another one that it increases the excretion of by activating the NRF2 pathway, which then downstream a lot of these phase 2 detoxification enzymes get activated. Right. For example. The other interesting thing is sweat. And, you know, there's been a variety of studies that have looked at which kind of, for example, heavy metals or other xenobiotics like parabens or BPA, things like that, which are excreted through a variety of different, you know, mechanisms. Some are excreted, you know, more prominently through urine and others through sweat. And so, things like exercise and even sauna bathing can, you know, for example, mercury is one that really is excreted through sweat. So, you might find that interesting.

I don't know if— Yeah, I've heard a little of this, but you've told me a lot of new stuff I absolutely didn't know. So, great. Yeah. Thanks for sharing that. Yeah. Now, Dr. Axel Montagne shares findings from animal models showing that mice develop blood-brain barrier breakdown and early signs of white matter damage just days after exposure to real-world air pollution. These changes mimic vascular dysfunction seen in humans with dementia, suggesting that pollution could be an underrecognized driver of cognitive decline, particularly in genetically susceptible individuals. He and I also discuss how elevating fibrinogen levels may be one mechanism behind the damage and how omega-3s may mitigate the pro-inflammatory response.

I was looking up omega-3 because I had remember— remembered coming across some studies with it. And interestingly, people, so air particulate matter, so when you have like air pollution particulate matter, when people are exposed to high amounts of it, it causes their fibrinogen to go up, right? It's again an inflammatory marker as well. But, people that were taking in high amounts of omega-3, it blunted the increase in fibrinogen in plasma. And so, it would be very interesting to see if in some of the animal models you were discussing if omega-3 could blunt, you know, the white matter dysfunction caused by fibrinogen. fibrinogen getting into the, into the brain. So again, it's another prevention, more, you know, easier low-hanging fruit thing that people can do now, right?

I mean, yes, making sure they're taking in enough omega-3. Yes, exactly. Um, no, I, I cannot agree more. Um, we don't want, don't need to repeat what we said, but yeah, there is this, uh, kind of vicious cycle where omega-3 may play a major role into, uh, vascular functions, of course. It's not even may play. I think that it does play a role, and it might play even a more important role in people at risk for Alzheimer's. It's possible, like the APOE4 carriers that we've talked about. And you mentioned, interestingly, you mentioned airborne particles like pollution, right? And it, I think it's linked to what we've said earlier. So there is Alzheimer's due to Keep it simple. If you think about Alzheimer's, it's a multifactorial disease.

So you have genetic risk, possibly you have, um, you have lifestyle, exercise and everything. But there is also an, an, uh, what we call environmental factors, and pollution is one. And, uh, there is multiple studies, as you know, showing that if you live in a city, big city, you have more chance to develop some sort of dementia. And I'm part of 2 studies that we've published, uh, 4 to 5 years ago maybe, where we, we exposed mice to airborne particles from Los Angeles. We're taking from the, the highway the particles and giving it to the mouse to see what's the impact of, uh, the pollution on vascular function. Because there's some evidence that also using scans, those people have, tend to have more white matter disease and things like that.

So we started looking into that and we found, very interestingly, we found a high peak of vascular— it's a longitudinal disease, but we very rapidly, a few days after giving the particles to the mouse, we were seeing blood-brain barrier breakdown and pericyte degeneration very quickly. One of the first signs that we could see. Of course, now there is debate on the mechanisms. whether the particles can penetrate into the brain through the, the olfactory area, or whether it's directly, uh, the particles in the bloodstream that activate maybe, as we said, the endothelium a bit too much, which will indirectly cause some vascular issues. That, I think there is more studies going on.

But definitely on environmental factors and pollution is a, a, a big thing to take into consideration when it comes to dementia and especially vascular function, because we breathe that every day, right? So, uh, this has to do something with vascular. So it's another factor, but I guess it's not good. I guess if you have ApoE4 and not doing exercise and living in a big city, you probably have much more chance to develop some sort of, uh, vascular problems as we know. But, but we try to understand how this is happening. Yes. I, I, I remember reading a study where babies, you know, in, in Mexico City postmortem, they found, I mean, unfortunately in babies, they had like all sorts of amyloid plaques in their brain and I don't think that's normal. And Mexico City is like, yeah.

Yeah, yeah, yeah. It's highly polluted. Highly polluted. Yeah. Yeah. It makes me wonder about filtering out the air. I mean, if there's some HEPA filter or something that helps a little bit, um, as well as omega-3 has been shown. I know I keep going back to that, but it's been shown to help blunt some of the air pollution. I know it's, it's, it's, you know, the research shows it, you know, so. Yeah. I mean, I don't know. I mean, if we, that'd be nice to, I'm pretty sure people are working on that, but there is some countries or cities that are wearing masks and things like that in China, for example. Uh, so that'd be, I guess it's hard.

It, it would be a long study, but I guess we could compare, uh, highly polluted cities and people wearing filtering and masks, things like that, to see whether they can preserve, preserve some vascular, better vascular functions and things like that. But yeah, I guess there's probably ongoing studies that, yeah. Now that we understand the risks of air pollution, let's shift towards mitigation. Let's start by reducing indoor exposure with a simple strategy, HEPA air filters. Listen as I explain from Q&A number 45. HEPA filters or air, high-quality air filters.

So we talked in this episode about air pollution being a major environmental factor that can increase the risk for Alzheimer's disease, particularly in people with an APOE4 allele who are genetically predisposed to later onset Alzheimer's disease. And a lot of that has to do honestly with increased inflammatory response in, in the body, so in circulation, but also in the brain. So there's been a couple of studies that have come out showing that particulate matter from air pollution does increase inflammatory molecules and inflammatory processes throughout circulation, but also directly in the brain. So So things that are inhaled through the nasal passages can sort of have a direct route across the blood-brain barrier, which is used pharmacologically.

There are some drugs that are administered intranasally that are, you know, trying to get into the brain. For, for example, oxytocin being one that doesn't readily cross the blood-brain barrier. If you're just taking an oxytocin supplement, for example, and it gets into circulation, that's not going to cross the blood-brain barrier. The way to do it would be to inhale it. So anyways, with respect to answering that question, so right now in my home, so I no longer live next to a busy road or I'm sort of like more in a nature type of environment. Took me a while to get there though. But I've, you know, since I've lived in very metropolitan areas, for most of my life, actually. I've had a— I wouldn't say it's a medical-grade HEPA filter.

It's one of those Honeywell HEPA filters that you, you know, you can have in each room. And so we have them in the bedrooms in our house, and we've considered and probably will go ahead and get a higher-quality medical-grade HEPA filter. And the one that we are looking into getting is from IQAir. It's pretty easy to remember. Lifestyle and dietary strategies may also help mitigate the risks of air pollution. In this segment, Dr. Jed Fahey and I discuss how bioactive compounds like sulforaphane found in broccoli sprouts activate detoxification pathways that increase the excretion of airborne toxins like benzene and acrolein. But sweating via exercise or sauna also helps eliminate heavy metals and other pollutants.

Together, these strategies may reduce the body's toxic burden And protect the brain and vascular health. The next question was, if I can't consume broccoli sprouts daily, how beneficial is it to consume them only after exposure to heavy air pollutants? As a firefighter, I am exposed to a lot of carcinogens during a fire, and I'm wondering if it's beneficial to only take them post-fire calls and for how many days? Yeah, another great question. And to the firefighter that asked that, thank you for your service. It's been a rough year for firefighters out west. That's for sure.

So, my best guess is that taking them regularly or taking a supplement in order to prime your system and get your antioxidant and detoxification system ready for the regular assaults that you're laying on your body, it would probably be wise. I think this is a case where you should remember that you if we're talking about carcinogens or toxins or oxidant chemicals, you never really know when you're being attacked by those vicious chemicals. And, I'm actually not exaggerating. I mean, there are a lot of nasty chemicals in smoke certainly from home fires and even from wildfires. So, if you look at the analogy to wearing seat belts, You wear a seatbelt not because you plan on getting in an accident, but it's prophylactic.

And, I think you could make a similar argument if you know you're regularly blasting your lungs and your body with the components of smoke. You could make an argument that priming your system to get that response maximally geared up would be a good thing. One thing we do know from our work in China with study of air pollution and the effects of sulforaphane on that is that you don't fatigue, and this is fortunate, but you don't fatigue the biochemical response system. So, for 12 weeks, we gave daily glucoraphanin and sulforaphane and monitored the upregulation of the this protective response and did not really see any fatiguing of the response of that system.

So, short answer then to the firefighter is, yeah, I think taking a supplement regularly would be— obviously, you're not going to make broccoli sprouts when you're out doing fire calls, but so probably supplements in your case would be a good Good thing. I'm not a physician. I'm not prescribing them to you, but that's the way I feel about it. Yeah. Jed, if I, I just could comment as well. Um, your, your, your 12-week study was, um, extremely relevant to not only firefighters, but, you know, people particularly on the West Coast in California and, you know, Oregon, you know, people that are being exposed to these wildfires that are breathing in acrolein, which is heavily in, in smoke and benzene.

But, you know, and, and your study showed that within 24 hours, benzene excretion was excreted by 60% and acrolein study was increased, acrolein excretion was increased by 20, about 23%. And so the, the, I guess also the question is, let's say, you know, the firefighter or whoever isn't gonna take it daily, but, you know, even within a few days of knowing they're going on call or whatever, do you think that would even be beneficial? Because, I mean, literally, this is in 24 hours, your study in China. Yeah, yeah. So, I do. I mean, obviously, there's some time lag between the time you ingest glucoraphanin or sulforaphane and the time the enzymes are upregulated or respond. It's quite short though. And, Even after a couple of hours, some of those enzymes are cranking up.

So, the answer to your question is yes. And, the main sort of situation where I think you might almost have to have it on board before an event is some of the neuronal injury models. Like, when we talk about traumatic brain injury and spinal cord injury, There is an absolutely pronounced effect of sulforaphane that we have seen in a variety of studies. We and others. When I say we, I always mean we and other people, or maybe I wasn't even involved in that study in this case, but we see an effect. Obviously, if you have that sort of injury and you're looking for the rapid response of sulforaphane, It would be ideal to have had it on board your body beforehand.

But, one of the things that appears evident is that with neuronal injury, even getting it right after the injury may have some value. So, with the fire analogy or the fire situation, absolutely, we showed that the response was upregulated quickly and it was maintained. And, as you say, Detoxification of 2 out of the 3 major pollutants that we looked at happened to a substantial degree. And I should mention this was work that my colleague Tom Kensler started a long time ago in China, and we joined in that work in the, I guess in about 2001. And so we've been involved with it for many years now. And, the final studies there are going to be published soon, I hope. Just amazing work. I love those studies.

And, the fact that the 12 weeks, there was no exhausting of the upregulation of these important detoxification enzymes, that's really profound that they were maintained within that whole 12-week. It wasn't like It was a short-term effect that went away. Finally, we'll take a look at how natural environments may offer a biological buffer against pollution. Spending time in green spaces has been shown to lower stress hormones and inflammatory markers compared to time spent in urban settings. While not a replacement for air quality interventions, regular exposure to nature may help offset the stress-related and inflammatory consequences of living in polluted areas. Listen as I 3 benefits to running in nature. Hi, I'm Rhonda Patrick. Just wrapped up day 6 of my Nature Run Every Day October.

First and foremost, lower levels of stress hormones like cortisol. Number 2, there's even more dramatic improvements in mood and lowering of depressive symptoms compared to running in urban environments. And number 3, cleaner air, less air pollution. Air pollution itself increases inflammatory biomarkers and increases inflammation and stress hormones. So let's talk about stress hormones like cortisol. So one study found that people that are urban dwellers, so they live in an urban environment, when they spend time out in nature, they can lower their cortisol levels by almost 10%. So cortisol is an important stress hormone. It rises in a very cyclical manner.

So it is involved in regulating circadian rhythm, how everything in our body is going in a certain, you know, along a clock in a certain rhythm. And cortisol is really high in the morning. It's involved in that, that morning awakening response, the cortisol awakening response. It helps, you know, increase energy to start the day. It's really important to have cortisol elevated during that time. However, the problem is chronic elevation of cortisol. Because cortisol is a steroid hormone, it regulates a significant portion of the human genome, almost 20%. So that's like 1 in 5 genes that are either turned on and activated or turned off and sort of depressed in response to elevation of cortisol. So if you think about it, you know, our body does things on a clock, right?

And, and so that cortisol is involved in making sure things are turned on at the right time and turned off at the right time. But when you have that chronic elevation of cortisol, the timing's all screwed up. So things are just on and off and on and off, like when they're not supposed to be. So it causes dysregulation in a lot of different physiological processes in the body. So lowering that chronic cortisol by about 10% is pretty significant. The other study that I'm interested in sort of telling you guys about is a study that compared people that did physical activity in either a metropolitan environment versus out in nature. And they did the same exercise protocol. I believe it was like a walk or something like that. I can't remember all the details.

But the study found that the people that did the nature exercise had drastic improvements in mood and a lowering of depressive symptoms compared to those that did the metropolitan exercise in an urban environment. And also just the air pollution itself, right? When you're out in an urban environment, There's so much more pollution from cars and a variety of other industrial factors. So, breathing in that air pollution itself has been shown to increase inflammatory biomarkers. So, again, chronic low-level inflammation is associated with brain aging, just aging in general, but also it's been shown to be associated with plaques and stuff in the brain. So, and potentially being correlated to Alzheimer's disease. So again, being out in nature, so many benefits, lowering of the stress response.

We get improvements in mood. We get decreases in depressive symptoms. And also, we're not— you have cleaner air. You're not breathing in that air pollution. So that's day 6 of Everyday October. I'm doing some form of deliberate exercise every day this month. I hope you guys can join me on this fun, fun time to Build healthy exercise habits. If you guys have any questions or comments about any of the studies or facts I talked about today, I look forward to reading your comments and responding. Thank you for listening to this Aloqua on environmental exposures and health. I hope you enjoyed listening, and I'll talk to you soon.