Episode transcript
Time stamps
00:58: Overview of Episode Theme: Climate Change and Food Allergy
01:20: Crash Course on Respiratory Allergies and Climate Change
02:12: Thunderstorm Asthma and Rain's Impact on Allergies
04:13: Pollution's Effect on Respiratory Allergies
06:09: Epithelial Barrier Hypothesis
09:25: Peanut Allergy and Climate Change
14:33: Eosinophilic Esophagitis (EoE) and Pollution
16:29: Geographic Impact on Allergy and Asthma
17:17: Local Allergen Profiles and Testing
Announcer:
ImmunoCAST is brought to you by Thermo Fisher Scientific, creators of ImmunoCAP™ specific IgE diagnostics and Phadia™ Laboratory Systems.
Gary Falcetano:
I'm Gary Falcetano, a licensed PA with over 11 years experience in allergy and immunology.
Luke Lemons:
And I'm Luke Lemons with over five years of experience writing for healthcare providers and educating on allergies. You're listening to ImmunoCAST, your source for medically and scientifically-backed allergy insights. On this episode of ImmunoCAST, we are going to zero in on a new study that came out in February 2024 around climate change and food allergy from Dr. Ashley Lee and Dr. Nicole Ramsey from Mount Sinai. This episode is going to be themed around climate change. We'll talk a little bit about respiratory allergies and climate change, but we'll really want to be talking about this study that came out in food allergies.
Gary Falcetano:
Exactly. I don't think we often think about food allergy being related to climate change, and they did a really nice job in this paper of going through each of the various presentations of food allergy, even things like eosinophilic esophagitis and how they may be related to our changing climate, warming climates, increased pollution, et cetera.
Luke Lemons:
But before we get into food allergy and climate change, let's do a quick crash course on respiratory allergies and climate change. We know that pollen season is starting earlier and lasting longer because of the environment and also these different seasons are overlapping with different allergies.
Gary Falcetano:
Exactly. We're seeing tree pollen season that starts earlier in the spring, continues into the summer, summer grass pollen seasons that start earlier. There's a lot of overlap and it makes differentiating just based on history, what someone may be allergic to pretty difficult.
Luke Lemons:
And this is why testing is so important during allergy seasons, is to be able to differentiate between a tree pollen allergy and a grass pollen allergy. But it's also weather in general that can affect allergies and let's say rain, while a patient may not be allergic to rain, there is a phenomenon called thunderstorm asthma.
Gary Falcetano:
And we've talked about this on previous episodes, but the thunderstorms actually cause this dramatic environmental change during the thunderstorm that actually pulverizes pollens. It allows them to be inhaled more easily, go deeper into the airways, causing more severe exacerbations of people with allergic asthma especially that are allergic to the pollens that are being pulverized.
Luke Lemons:
And it's not just the thunderstorm aspect of it's also the rain part, the wetness. We see with increased amounts of rain, more mold allergies. We see this also with natural disasters like hurricanes and the aftermath, the increase of mold in environments that were hit by a hurricane. And this precipitation also affects dust mites.
Gary Falcetano:
We've talked about that as well. The way that dust mites thrive, the way they get the water that they need is actually absorbing it through their carapaces or their shells. Increased humidity levels increase the amount of dust mites in the environment, again, increasing dust mite sensitizations and eventually allergy.
Luke Lemons:
And you would think I'm somebody who might have a dust mite allergy, they probably have dust mites in their bed and they get a humidifier to think that, "This is going to help me breathe easier." But you're really just watering the little guys that are making you have an allergy.
Gary Falcetano:
I often call it the drinking fountain for dust mites and for molds. Climate change increases can certainly increase the amount of humidity in the air. We don't need to do anything else on our own to do that, like putting a humidifier in the bedroom if we're allergic to mold or dust mites.
Luke Lemons:
And I'm glad you mentioned mold again too, because we're seeing over the past 20 years, the seasonal length and the number of active weeks of exposure to outdoor molds in the late summer and early fall has increased as well, but it's not just the weather and the temperature and these storms that may increase allergy symptoms, it's also pollution has a direct effect on respiratory allergies.
Gary Falcetano:
For sure. We know that when an environment has increased CO2 levels, it's more beneficial to most plants or to a lot of plants resulting in increased growth, increased size of the plants, increased pollination, increased pollen being produced from the plants. That certainly plays into an increase in allergy, but there's other things as well.
Luke Lemons:
And CO2, some plants benefit more from it than others. For example, Bermuda and Johnson grass and weeds in general benefit from more CO2, and this allows them to spread more and to grow into areas that maybe that they wouldn't grow into. On the other end, Timothy grass and ryegrass don't necessarily benefit as much, they may even lose out competition for area against these other grasses.
Gary Falcetano:
Exactly. I think we're seeing some of that, we're seeing some spread north of the Bermuda and the Johnson grasses with the increased CO2 in the environment and their ability to really thrive when there's increased CO2. And the other thing is most weeds also do better in increased CO2 environment. We're seeing a proliferation really of weeds secondary to that increased CO2 in the environment.
Luke Lemons:
And while humidity does affect mold growth, CO2 concentrations also affect mold growth. And we see that with certain species of mold, they grow three times the number of spores and produce twice the amount of antigenic proteins that cause an allergic reaction or sensitization.
Gary Falcetano:
Outside of CO2, I think CO2 is what we always hear about when we talk about climate change, but outside of that, there are a lot of other things in the air. Things like nitrogen dioxide, ozone, particulate matter in general. And those all come into play when we're talking about an increase in allergies for several reasons.
Luke Lemons:
And what you're getting at here is the epithelial barrier hypothesis. Can you talk a little bit more about that, Gary?
Gary Falcetano:
I think in the last few years we've really come to the conclusion and when I say, "We," the allergy community in general has come to the conclusion that a lot of allergy is being caused or precipitated by a disrupted epithelial barrier, and that could be within the gut, it could be within the respiratory tract or even the skin. We know that children that have atopic dermatitis, when we think about the atopic march, that's one of the early signs of the atopic march, they have a disrupted epithelial barrier because of the atopic dermatitis, they're much more prone to develop a food allergy because of that.
Luke Lemons:
In this hypothesis is really the backbone of this paper by Dr. Lee and Dr. Ramsey around climate change and food allergy because these different types of particular matter can affect the epithelial barrier and damage it, it leads to a greater risk of exposure to allergens and sensitization, which in turn can lead to a clinical allergy.
Gary Falcetano:
That's exactly right. They speak to the environmental toxins, those things like the nitrogen dioxides, the ozone levels that are really implicated in the epithelial barrier disruption.
Luke Lemons:
And they mention actually in this paper a large Chinese cohort study in which they found that children who were exposed to outdoor pollution, particularly nitrogen dioxide, had an increase of food allergy. And this is because of this epithelial barrier being breached and exposed.
Gary Falcetano:
At least that's the hypothesis, right?
Luke Lemons:
Yes.
Gary Falcetano:
But there's other ways that people become sensitized through the skin, not just through epithelial barrier dysfunction.
Luke Lemons:
Exactly. And this is the case for Alpha-gal syndrome, which we had just talked about in an episode. Go back and listen to that if you're curious about it. But Alpha-gal syndrome is actually caused by tick bites and it can cause patients to develop a red meat allergy.
Gary Falcetano:
The sensitization happens through the skin. Just like we're talking about the pollutants disrupting the epithelial barrier, allowing allergens to be absorbed in a more intact format causing sensitization allergy, the same thing is true when we're talking about ticks and tick bites, they sensitize patients to Alpha-gal through the skin, and that seems to be a really potent avenue of sensitization
Luke Lemons:
And fun fact about that while we're on it before we go a little bit deeper into the epithelial barrier hypothesis, ticks the quest more. I learned this word ticks quest more when there's a high humidity and precipitation. You can also say that's climate change and food allergy. Questing is when they climb up on a leaf or a stick and stick out their legs and try to grab onto somebody to bite them.
Gary Falcetano:
Exactly. Whether it's us or whether it's a deer that's walking by that questing behavior is them reaching out to attach themselves to a mammal. And you're right, I think we both learned this together when we were researching this, but high humidity and warm days increases their behavior really hot dry days, decrease it because they hide, they get into the leaves and protect themselves from the heat and dryness.
Luke Lemons:
But getting back into this paper by Dr. Lee and Dr. Ramsey, they actually look at peanut allergy and its relation to climate change.
Gary Falcetano:
They mentioned this really it's a mycotoxigenic fungi and it's called deoxynivalenol. And what this substance, this mycotoxin does is it disrupts epithelial barrier function and it specifically in mice studies. They're trying to correlate it now to humans, but in the mice studies, it disrupts their epithelial barrier. And I'll let you talk about what they've seen in these studies around peanut and egg, but it seems to be an important player
Luke Lemons:
And increased levels of CO2 have been proposed to influence this fungi's contamination in crops. We think that the more pollution there may be, the more that this fungi spreads. And in this study they say that the elevated CO2 levels have actually, it's being proposed to influence the degree in which this fungi contaminates crops like barley, corn, wheat. But in these mouse studies, they found that mice who were fed barley, wheat and corn that was contaminated by this fungi actually developed a peanut allergy, increased sensitization and allergy to peanuts.
Gary Falcetano:
It acts like an adjuvant, it made the mice more susceptible to both sensitization and clinical allergy, and you usually do this for me, Luke, I'm going to try to simplify what you just said. And basically because of climate change, we're seeing an increase of this Dawn, this deoxynivalenol on crops, and this Dawn actually, it directly impacts epithelial barrier function in the mice, and they're proposing probably in humans as well, and specifically we're talking about the gut because we would ingest the corn, barley, wheat disrupt the epithelial barrier in the gut, allowing for increased sensitization.
Luke Lemons:
And they also looked at the offspring born from mothers without a Dawn-contaminated diet, and found that those that were fed Dawn, their offspring actually were more susceptible to an egg allergy than those who weren't.
Gary Falcetano:
Around peanut in those studies, it directly affected the mice that were exposed and in the egg studies, they also found it wasn't only the mice that were affected but the offspring, which I think is really very interesting, meaning that it'll actually affect potentially offspring in humans as well.
Luke Lemons:
And I think it's worth saying that it's not that the egg is all of a sudden related to Dawn or peanut specifically, it's just these are the lenses that these researchers used to examine an allergy.
Gary Falcetano:
Exactly. When they do these mice studies, especially egg ovalbumin is something they use a lot in looking at the mechanistic effects of allergy.
Luke Lemons:
Another interesting point that they bring up in this paper is actually around allergen components and peanuts specifically. We have an episode on food allergen components if you're curious about that, but they look at the RAH1 protein, and they find that elevated levels of CO2 are associated with an increase in this protein in peanuts.
Gary Falcetano:
I have never seen this before, and we know that elevated levels of CO2 increase the crop yields and they potentially make crops bigger, but this is the first time they actually looked at allergenic proteins within in a food, in this case, peanuts and RAH1, as we know is a storage protein. It's a very stable protein. It's associated with clinical allergy, to think that climate change is actually making peanuts more allergenic, I think that this is the first time I've seen that.
Luke Lemons:
It's very interesting and there is testing for this type of food allergen component. There are panels out there with reflexes to it, and again, I advise if you're curious about food allergen components, just taking a moment to listen to our other episode on that. But back to this study, they actually looked at two different types of peanuts and they over a two-year period had grown them in conditions where there was a lot of CO2 and conditions where there wasn't, and they found that the plants that were grown in high levels of CO2 ended up with this increased seed yield and increased RAH1 levels.
Gary Falcetano:
And whether that translates to real-world conditions in the fields, in the peanut fields, I think still remains to be seen. Under these controlled conditions, it definitely showed an increase in the production of RAH1.
Luke Lemons:
And I think that's worth saying, Gary, because this study isn't looking at what's happening out in the whole world with pollution and levels of RAH1 in crop fields for peanuts. They're looking more in a laboratory setting, but it's still very interesting to think that pollution, CO2 and the epithelial barrier being damaged can affect food allergies.
Gary Falcetano:
This paper does a really nice job of working through all of that, and I would definitely recommend to our listeners, it'll be in our show notes, definitely take the time and read this if you have interest in the role that climate is playing in potential food allergies. Luke, there's one more thing that I think we should discuss that was also mentioned in this paper, and that's eosinophilic esophagitis or EoE, and there was a couple of call-outs in this paper around EoE. We know that patients with EoE typically have worse symptoms during peak pollen seasons, and there is a correlation between pollen and EoE, that would be expected, I definitely understand that and I think it's pretty easy for our listeners to do that. But they also mentioned that actually the pollution itself actually has an impact on the mucosal barrier in the esophagus, and they showed that patients with exposure to increased levels of pollution actually had more symptoms due to their EoE, more food that were related to the eosinophilic esophagitis.
Luke Lemons:
And it was actually by five-fold looking at a case in Utah specifically, the food impaction increased five-fold when exposed.
Gary Falcetano:
That's right. That was an emergency department study out of Utah. Interesting stuff. There's a lot of impact I think that we're seeing both on just generally warming of the earth, but also especially related to pollution and its impact on allergy. I was recently at a conference where I heard a presentation around neighborhood geographic areas and how moving children out of certain areas of high pollution in a city to an area very close that has lower levels of pollution actually dramatically impacted their allergy and their asthma.
Luke Lemons:
We're going to be learning more and more about the climate's effect on allergies as researchers continue to do great work like this. I'm really interested to read more on food allergies and the relation with climate change. This was a great paper. In geography, we see not just with air pollution impacts patients, when we look at specific geographical species of plants and pollens, and there are respiratory panels that test for location-specific allergens. You can find these, they'll be linked on this episode's page on thermofisher.com/immunoCAST. We actually have specific profiles from laboratories across the country, laboratories that you most likely use that are designed to have the most impactful local allergens.
Gary Falcetano:
We've mentioned this on previous, Luke, these laboratories have designed geographic profiles that include the most common grass, trees and weeds in that geography along with the indoor allergens. And we can constantly work with our laboratory partners to make sure that these are the most relevant profiles and to see if, based upon changes in sensitization patterns, whether these may need to be updated somewhat in the future.
Luke Lemons:
A good example would be who knows in the future we mentioned Bermuda and Johnson grass benefiting more from CO2 and spreading into more areas, it may be while we consistently assess the changes in sensitization patterns, that labs will include more Johnson and Bermuda grass tests in more areas.
Gary Falcetano:
Exactly. Further, some of those northern geographies may need to start including those grasses.
Luke Lemons:
We hope you enjoyed this episode of ImmunoCAST. Again, we will have all these at thermofisher.com/immunoCAST on this episode specific page, and there's also a link to that page in this episode's description. Thank you for listening.
Gary Falcetano:
Thanks so much. We'll see you next time.
Speaker 1:
ImmunoCAST is brought to you by Thermo Fisher Scientific, creators of ImmunoCAP Specific IgE Diagnostics and Phadia Laboratory Systems. For more information on allergies and specific IgE testing, please visit thermofisher.com/immunoCAST. Specific IgE testing is an aid to healthcare providers in the diagnosis of allergy and cannot alone diagnose a clinical allergy. Clinical history alongside specific IgE testing is needed to diagnose a clinical allergy. The content of this podcast is not intended to be and should not be interpreted as or substitute professional medical advice, diagnosis or treatment. Any medical questions pertaining to one's own health should be discussed with a healthcare provider.
