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#02 – On The Front Lines of Toxic Black Mold Illness with Dr. Neil Nathan

If you have any symptoms at all, listen to them. It’s your body’s way of trying to communicate with you. If you sit on these symptoms, it will just get worse.

Dr. Neil Nathan

Our world is changing rapidly and there is much we can learn from the reactions of the most sensitive among us. What may seem like harmless scents or supplements to most of us, will cause a special class of chronically ill patients to develop severe reactions. Why are people reacting in this way? A growing chorus of physicians believes exposure to mold toxins is at the root of many of the diseases of our time. In this episode, we will hear the stories of “canaries in the coal mine” who became so sensitive, they couldn’t even stand to be around people who washed their clothing in certain detergents without reacting violently. We will also hear how they healed.


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Today our guest is Dr. Neil Nathan M.D., a physician specializing in mold toxicity, chronic Lyme and chemical sensitivity in Northern California. Dr. Nathan has been practicing medicine for over 40 years, with his practice now focused on complex cases of chronic illness brought on by Lyme disease and mold toxicity. He attended the Pritzkin School of Medicine at the University of Chicago and is a founding diplomat of the American Board of Integrative and Holistic Medicine. He has written several books including Mold and Mycotoxins: Current Evaluation and Treatment as well as his most recent book Toxic.

This Episode Covers:

  • The importance of following intuition when it comes to scents and reactions to chemicals [4:30];
  • Karen’s story: a story of chronic illness, Lyme and chemical sensitivity [5:50];
  • Identifying symptoms of multiple chemical sensitivity [10:20];
  • Are mycotoxins in food dangerous? Dr. Nathan discusses a mycotoxin experiment he ran with Great Plains Lab [13:50];
  • The role of ambient mold, mold avoidance and air quality in chronic illness [19:45];
  • Glyphosate in food [26:00];
  • The wisdom of micro-dosing supplements. choosing a B vitamin, and methylation [28:00];
  • Mast cell activation and the “trigger finger” immune system reaction [36:30];
  • The changing landscape of food sensitivity and water allergy [39:20]


John: Welcome to the ”GeneFood” podcast. I’m your host John O’Connor. Today our guest is Dr. Neil Nathan. Dr. Nathan is a board certified family physician and a founding diplomat of the American Board of Integrative and Holistic Medicine. Dr. Nathan attended medical school at the University of Chicago Pritzker School of Medicine and he has devoted much of his 44-year career to helping treat complex cases of debilitating illness such as Fibromyalgia, Lyme disease, chronic fatigue and pain, as well as mold toxicity. He’s authored several books including ”On Hope and Healing,” ”Mold and Mycotoxins: Current Evaluation and Treatment” as well as his latest book, ”Toxic.”

I think there’s a lot to learn from Dr. Nathan. He’s treating patients that are very sensitive and are suffering from very severe illness, but there are lessons in his treatment regimens that we can all use in crafting a supplement plan or just living healthier lives. So I’m excited to learn from him. And without further ado, here’s Dr. Nathan.

Your practice is in northern California and has been for quite some time, right? Could just tell the audience in terms of location wise, are you north of San Francisco, is that right? Or, where are you?

Dr. Nathan: Yes, we’re about 150 miles north of San Francisco.

John: Okay, cool. And when you dive into the book after you get past the dedication to your wife, the first thing that popped out to me was the first image that you have on page 11 of the book is of the smokestacks. And it’s a theme that runs through the book that there’s a growing toxicity in the world that we’re seeing with chemicals and all sorts of different things that are sort of, that weren’t there before. Can you speak to that a little bit in terms of from 10,000 feet? And I’m sitting here in New York City and should I be concerned? I mean, Tell us your take on this?

Dr. Nathan: The answer is from my perspective, yes. Many people who work in this field. One of the things we’re all agreed on, even though we don’t have the science to prove it as conclusively as others would like, that the world we’re living in is increasingly toxic. And I will be happy to talk about that in any detail you want to.

John: Well, I’d like for you to address it in detail because there’s a lot we want to get into here. I wanna get into some of this into some of the stories of your patients, like Karen’s story that you share in the book, which are absolutely fascinating. But to reach the largest audience, it seems to me anecdotally that there is a growing group of people who seem to be sensitive to their environment, maybe not to the level that you’re seeing with your patients, but they sense something’s a little bit wrong. And what are some things to look for in the environment that you see as being troublesome, you know, as we move forward with technology?

Dr. Nathan: Well, I don’t know that it’s looking at the environment as much as I think one of the illnesses of our current world that is not discussed, I would call it numbness. I think you can see the effects of that numbness in such things as the increasing violence in all the movies that we show. I think that in order to even reach people, the Hollywood realizes that it needs an increasing intensity or visual imagery for people to even be affected. I think we can see it in multiple other ways where the electronic world that we live in is such that we don’t make eye to eye contact with people, which is the essence of all human interaction. And I think that numbness extends itself to people not paying attention to how their body reacts to being in a variety of situations.

And so you might, for example, wrinkle your nose as you walk down the scented detergent aisle of the supermarket and not realize that it may actually be impacting you, but you’re not noticing that, or walking into certain stores at the mall where scented products are prominent and going, you know, I don’t really wanna be in here, but not really noticing how your body is responding. And I think that’s really a more common phenomenon than people realize.

John: Right. And so it ties in well with your message in the book, too, which is that people that have these sensitivities are often robbed of their insight I think is a way you could say it because their social circle tells them, well that’s not possible. You know that must be all in your head. You know, you must be imagining that you share a story in the book of Karen. Karen develops Lyme disease. Basically, she becomes terribly ill. And can you speak to that? This idea that there are people that really are having these issues and, and kind of how you decipher something that’s psychosomatic from something that’s happening physiologically in their body.

Dr. Nathan: Yeah, of course. Okay. So, first of all, Karen’s not her real name to protect her privacy, but she has given me permission to share her story. I do use it as a teaching tool. I think it points out a lot of important information. She lived in northern California and had been walking her dogs in the woods. They came back loaded with ticks and she didn’t think much about it until about three weeks later when she came down with what looked like a flu. Now, fortunately, she got into the hands of doctors who had heard of and knew how to treat Lyme disease early and she got some treatment for Lyme disease, but it wasn’t as effective as they had hoped. And she slowly got worse and worse in terms of neurological events in which she would suddenly start riving and twisting and moving, falling on the floor and something that looks like a seizure.

I have videos of that which I use in some of my medical presentations to show audience members what that looks like. But your listeners, John, could view it as looking like a seizure but not quite. Technically in medicine we call that a pseudo seizure. It’s actually a true neurological event. It just doesn’t show up as an EEG positive when neurologists look at it. And she began to have these, not only randomly, but particularly when she would be in church or at the grocery store, when she was exposed to a variety of scents, either perfumes or, as we mentioned, the detergent dial at the grocery store where she would literally fall down and people would get freaked out and they would call the emergency room and she would go there and they would not know what was really going on for her.

She went on like this, increasingly getting worse till she was confined to a wheelchair when I saw her a number of years ago. And what it seemed to me at that time, we slowly figured it out that not only did she have one of the co-infections of Lyme disease called Bartonella, but she also had mold toxicity. And she was so sensitive at that point that she could only take minuscule doses of the medications that we use to treat those illnesses. But we proceeded very slowly, very carefully. As we realized she had mold toxicity, she had mold remediators come to our home and clean it up. Very, very slowly. She got better. But during that time, we would see things like, she would literally be walking down the halls of our office, walking fine, and all of a sudden fall down on the floor and start riving.

And we would discover the one of our office staff who washed her clothes in the detergent tide was at risk. Meaning this happened with enormous consistency. It took us a long time to figure it out. This was clearly not psychogenic. I mean she simply walking down the hall with me talking and all of a sudden she’s on the floor. And we’re going, “What?” But as we evaluated this, we discovered that the detergent that she was being exposed to by scent was the culprit. And we then treated, this is technically known in medicine as multiple chemical sensitivity. It’s a very real phenomena in which any number of chemicals in the environment can trigger a wide variety of events. The hallmark of multiple chemical sensitivity is a virtual instantaneous reaction on the part of the person who unfortunately has had this sensitization process in which literally within seconds of exposure to some scent, now, it can be cigarette smoke, wood smoke, fire scent. It can be detergents, chemicals of any type. And the reactions can vary a bit, but it is almost instantaneous perception of profound weakness, fatigue, brain fog or neurological events like the ones we’re seeing here.

So other people look at it and go, oh, that’s not pocketable. And there are well over a million people in this country who have multiple chemical sensitivity. So it is not only possible it’s happening, and often these patients are simply not believed by their family, friends, even their physicians. So this is a very real non-psychological issue, which is treatable, and Karen is a very excellent example of that. Over time, we were able to treat her, get the mold out of her tissues. We’re able to successfully treat the Bartonella and Lyme and she is now able to go on 100-mile bicycle marathon runs and do virtually anything she wants. And she’s currently in practice as a consultant now paying it forward, helping other people who share her story.

John: Very cool. And so for the listener, Dr. Nathan has testing protocols that he uses to identify these different toxins. So can you tell us in her story, obviously not her real name, Karen, what did some of her testing look like that put you in this position where you’re like, “Okay, I know what I’m looking at.” For example, the mycotoxin panels that you run.

Dr. Nathan: Well, for Karen, I treated her before the mycotoxin panel was available. So that’s not a good example. She did test positive for Lyme and Bartonella and Babesia on blood testing. So that was something that was well confirmed. The testing we had for her back in those days was much more primitive. It included something which we call visual contrast sensitivity, which is the pest that your listeners can get online through the website, but that’s a very primitive test and is not specific for mold. What we have now is infinitely better. We have several laboratories namely the Great Plains Laboratory and Realtime Laboratory that are able to take a specimen of urine and analyze it for the presence of mold toxins, which we technically call mycotoxins and actually measure which toxins are in the body and how much of it there is. So this is something we are now able to measure quite accurately and to really get a clear bead on what’s going on.

John: Yeah. And can you tell us? So it’s basically a urine test that you have to have a doctor order for you for these labs. And, you know, one of the things that’s really a hot topic out there in the integrative health and sort of like, for lack of a better term, biohacking community are mycotoxins in food. You know, there’s whole coffee companies that have sprung up saying, you know, “We’re mycotoxin-free coffee.” And it’s not to sort of marginalize that argument, but I’m wondering, somebody like you who sees these patients who are suffering from mold illness, what role do you see the mycotoxin in food issue as having in treating these patients?

Dr. Nathan: Well, I mean, John, that’s an interesting question and fairly controversial, but we have some brand-new research to shed some light on it. So first of all, giving you my biases, which are the major exposure to mold toxin comes from water damage buildings. There’s a reason for that, which is we’re doing this broadcast and I live in northern California and I’m looking out my window with the Redwoods and because that’s where I live. And in my environment, there are probably a thousand species of mold sitting out there in my backyard and front yard. All but seven of those species are not toxic to humans. And molds in the natural world make mycotoxins to keep other mold species out of their ecological niche. So we have molds that prefer Redwoods, or Tan Oaks, or Rhododendrons, or as Azaleas, or so each tiny part of the ecological niche attract certain mold species that prefers to be in that niche and they make their mycotoxins just to keep others out of their turf.

So you can have mold allergy in the outside world, but you’re generally not gonna get any mold toxicity from that exposure because it’s not enough of it to actually bother anybody. However, in a water-damaged building, those toxic mold species can grow on a posed and you can get massive quantities of mold producing massive quantities of toxins. And that’s the issue. Okay. So outside mold is not an issue, but those mold spores in a building release the spores and the fungal fragments and the mycotoxins, which are basically teeny, teeny materials. The spores are microscopic and typically they get more into the lung not to infect it, but to release their toxins. And that’s the primary source of toxicity.

So we do know that to a limited extent, food can become moldy. And there are, for example, a number of papers in the medical literature showing that if you have a particularly moldy silo filled with grain, you can really do damage to a number of people. But that is the exception rather than the rule. So many, many foods are known to potentially be moldy. Coffee as you’re pointing out is one of them. Grains, fermented foods, tomatoes, and on and on and on. There’s a number of foods that are associated with the possibility that they would contain a significant amount of mold toxins. And it has been proposed by some that the primary source of mold toxicity is our food, and I would like to suggest that that is not true. It’s never seemed true to me. We’ve just done a study with the Great Plains Laboratory, which went something like this. We took 10 of our patients and we have them avoid all potentially moldy foods for 10 days. At that point we got a mycotoxin urine test on them. We then have them pig out on those foods for 10 days and then repeated the urine. And what we discovered was actually a little bit surprising.

I only have results back for six of the first 10 people to participate and five of those, the mold levels went down when they ate purportedly moldy foods. In one patient, there was a slight increase, particularly an Okra toxin, which is probably the main mycotoxin that you’ll get out of food if you’re gonna get any at all. So first of all, I don’t believe that there is a significant amount of mycotoxins in the food we eat generally. That doesn’t mean go ahead and eat moldy food from your refrigerator. Absolutely not. But in general, the foods that can potentially contain mold do not contain enough to make people unhealthy and then you’ll see all these websites saying, you’ve gotta have bulletproof coffee because it does not contain any mold.

Now, I would go to expand on that just for a second. I do suspect that certain people are genetically more predisposed to handling mold toxin with more difficulty and I’m sure that we will find selected individuals where the minimal toxins in food may play a role for them. I don’t think it’s gonna be the biggest role. I think the inhaled mycotoxins from water-damaged buildings are the biggest culprit, but I think we will discover that in a few people, yes, it plays a small role.

John: So there’s a bio-individuality to it. I wanna piggyback on that. And you say the inhaled mold because one of the things I think is really interesting in this universe of mold toxicity and people trying to diagnose these sort of unaccounted for chronic problems that they’re having is air quality. We touched on at the beginning of the podcast, you’re talking about the rise in certain manmade inorganic pollutants, things of that nature. There are people out there, there’s groups, there’s a group, it’s called the Locations Effect Group. I’m not sure if you’ve brushed up against this in your work, but they practice what’s called a mold avoidance lifestyle. So they will literally take an RV and they’ll go out and they will live in environments where they feel like they are better off because there’s no mold in the actual outdoor air. And having lived in Austin in the past, I do know that the mold spore account in that city, which is a phenomenal city. I love Austin. I have nothing but positive to say about it. But the mold spore count in Austin, in Texas hill country and some of these invariants would get very high. What’s your sense of things in terms of taking the moldy building side, which we know is an issue? And then how about inhaled mold from just the environment?

Dr. Nathan: Well, again, you know, when you get a mold count, you don’t usually see the individual mold species listed. And, again, only seven or eight specific mold species are actually toxic. Now, when the mold count is high, allergy can certainly be an issue. So I’m not debating the allergic component, but mold toxicity and mold allergy are really different creatures. One of them looks like allergy, meaning itchy, runny eyes, congestion, you know, throat that feels a little bit off asthma sometimes those are allergy symptoms. Mold toxicity is a much, much more profound illness involving intense anxiety, depression, joint pain, muscle pain, again, shortness of breath due to toxicity, not to allergy. All kinds of intestinal issues, severe diarrhea, constipation, heartburn, abdominal pain and increased sensitivity is caused by mold. Sensitivity light, sound, EMF of food, chemicals. So all of these things are a much different creature than merely being exposed to mold and ambient air.

In terms of the group that you’re talking about, which I do know something about, some patients who I’ve had mold toxicity have become understandably almost paranoid about their exposure to mold. And to a certain extent, treatment involves balance, meaning if your fear of mold exposure becomes overwhelming, part of the problem that mold toxicity triggers is what we call limbic dysfunction. The limbic system is the part of the brain that controls emotion and sensitivity, cognition, pain and energy, which is symptomatic for many of our patients. And we’ve learnt that the inflammation and dysfunction, the limbic system has to be treated and rebooted for those patients to get well. Those patients who have gotten really, really caught up in mold avoidance, I fear have a limbic issue that they’ve not addressed. They’re living in fear and that adds to the problem and makes it very difficult for them to get well.

John: Yeah. And that’s an important point I think you’re making, which is that we don’t wanna marginalize anybody’s experience, but there is this balance between identifying things in the environment that are harming you and developing an attitude that, you know, all you see is potential harm. I think that’s a great point for people who have had, you know, we know these cases, Karen story, the people that have had these really severe issues. Can you speak to somebody at home who might not have something that’s terribly debilitating but is feeling as though they have some of these symptoms that are consistent with some low-grade mold issue? You know, maybe GI issues, perhaps sinus, cold hands and feet, things like that, that seemed to be growing with increasing prevalence. Like, what do you say to the people who are kind of looking to optimize who but who aren’t, you know, bedridden like some of your very sensitive canary in the coal mine patients?

Dr. Nathan: Well, right. My message to everyone is if you have any symptoms at all, listen to them. It’s your body’s way of trying to communicate with you and say, “Hey, I’ve got something going on here. Pay attention, and if you can figure it out, do something about it.” If you sit on these symptoms and you have some degree of toxicity, it’ll just get worse. If you let it accumulate that toxicity in our environment, it’s cumulative. There are 80,000 chemicals in our environment that are new in the last 40 years that we’ve never tested. Of those 80,000 chemicals, only 500 have ever been tested for their safety in human beings. So there’s a massive influx of chemicals in our environment that we know are not safe. Maybe the most prominent of them, and one of the most toxic many people don’t realize is those that contain glyphosate, which is the major ingredient in roundup.

So if people are not eating organic food and they’re particularly eating a lot of foods that are known to contain roundup, like grains, corn, soy, etc., they are exposing their body to toxins that will make their liver have to work overtime to get rid of it. And so our livers are currently being taxed to try to process these toxins in a way that has never been experienced in human society before. S, I think it’s really important that people not blow off what they might think are minor symptoms rather to pay attention to it and go, “Huh, maybe I should be doing something about it. Maybe I need to be doing something in the supplement category to support my liver to make more glutathione to processes toxins better to help my gallbladder work better, to process these toxins, to help my gut work better, to help get this stuff out.” And I think that would be my message for people having minor symptoms. If you ignore them, there’s a significant possibility they’ll get worse and that is not gonna be of help to you. At a certain point, you will cross some threshold where it isn’t gonna be easy to fix it, it’s gonna get very complicated.

John: Sure. I mean that’s when you get in a pit and you have to dig a lot harder to get out. And you touched on supplements, you have a very interesting approach to supplements in your book. And I think there’s some wisdom with how you discuss supplements that everybody can take some value from. You know, you say take supplements that can improve the function of the liver and glutathione. And what we see out there is there’s so there’s so much hunger for this information. People are out there, they’re reading the blogs, they’re seeing the theorized benefits of supplement A, B, and C. And then they’re taking, you know, 15, 20 at a time and they’re taking these really high doses. And one of the things that’s fascinating in your book is this approach you take with micro dosing supplements and really balancing in the regimen and the dose that you give to these patients. Can you speak to that and tell us I think the listeners would be shocked to learn just the tiny amounts of these different supplements that you offer up and why you take that approach?

Dr. Nathan: Sure. One of my mantras is if some is good, more is not necessarily better. And let’s take methylation as an example of that. Your listeners may not know that I publish, I wrote with Richman Kanoya Annenberg. We did one of the first major studies on the benefits of methylation supplements in treating patients with chronic fatigue and fibromyalgia. We did this back in 2007, we had a research grant and we took 30 patients with documented chronic fatigue and fibromyalgia. We measured their ability to methalate. We did check snips, but the actual measurements we’re measuring many of the components of methylation, meaning the various folic acid derivatives that constitute the folic acid cycle. We measured, FAM, SAH, Adenosine, reduced and oxidized glutathione, which are the major components of how the body makes glutathione through the methylation cycle.

So we did a before and after and we put patients on 200 micrograms of five methyltetrahydrofolic and two milligrams of Hydroxy B12. And in three months, we had normalized many of them. By six to nine months, and this was a long study and patients stayed with us during the whole time, we normalized methylation and every single patient on those doses.

John: Sorry, I just I wanna continue on this path, but just for the listeners who aren’t familiar. So can you speak to the difference between the forms of a folate and B12 that you used versus what’s out there and some fortified foods because you’re using methylated B vitamins to do this, correct?

Dr. Nathan: Correct.

John: What are those for the listeners that don’t know?

Dr. Nathan: I’ll make a few comments which may surprise some people. First of all, many people do not know that methyl B12, which is used in many of the protocols, actually has a feedback loop in the body. So when you take methyl B12 it goes, “Okay, you’ve got all the methyl B12 you need, I’ll stop making it,” which is a major component of the cycles of methylation. If you use it instead hydroxy B12 that doesn’t happen. So you can feed the body B12 in a much more effective way by using hydroxy B12 rather than methyl B12.

John: Interesting. So, Dr. Nathan, one of the things I’ve heard, just again as an aside here, is that hydroxy B12 was problematic for some people because it inhibited nitric oxide synthesis. What say you on that?

Dr. Nathan: Well, I think that’s completely erroneous.

John: Okay, good, good. That’s what I need. We wanna hear your opinion. So tell us why.

Dr. Nathan: The nitric acid cycle or the ONO cycle is fed by methylation. So anything you do to shut down methylation that messes with the cycle. But if you feed methylation as you would with hydoxy B12 that is much less likely to happen.

John: Interesting. Were you using standalone supplements? Or did you use like a B complex?

Dr. Nathan: We use stand alone? We used exclusively hydroxy B12 and we used a small amount of five methyltetrahydrofolate. Now, in most supplements keeping in mind where you only used 200 micrograms of the five methyltetrahydrofolate. Most of them have 800 micrograms and far as many have as much as five milligrams or more. From my perspective, that’s overkill. And again, the concept that of some is good, more will be better, does not apply to most patients. The body just wants what it wants and if you give it more than it needs, you’re gonna make it work to eliminate that extra supplement. And my thesis is it’s already working too hard. It’s already moving heaven and earth to get the toxins in it out. And even though this is not technically toxic, it’s one more thing the body has to get rid of. So taking supplements in excessive dose think that you’ll get more out of it, isn’t a concept that I would encourage people to embrace.

John: I think that’s a message that just needs to be shouted from the rooftops for all people that are taking supplements. I think it’s very, very important. Just to finish out on this, this methylation study, so you found that the small doses of specific forms of B vitamins were able to really alter and change these biomarkers in a positive way. And did you look at MTHFR in any of this work?

Dr. Nathan: We did. One of the consultants for this study was Amy Yasko, who is one of the people who’s pioneered the use of these. Amy designated and measured for us five specific snips that she thought would be relevant to our study. And we found that most of our patients had abnormal snips.

John: So it was MTHFR, was it MTRR what were some of the snips, the genes that you were looking at for that Amy Yasko identified?

Dr. Nathan: This was so long ago, I don’t remember which ones Amy designated. But the take home message is regardless of Hetero or homozygosity to snips, every single patient normalized methylation using this protocol.

John: Wow. And what was biomarker or the series of biomarkers that gave you the assurance that the methylation had been normalized?

Dr. Nathan: Well, virtually all of our patients on their initial test had abnormal components of the methylation blood tests that we did. For example, almost all of them were low on Sammy, almost all of them low on reduced glutathione, which are the two major markers that we’re looking at. And all of them normalized those markers by the end of the study.

John: So they increased the levels of natural antioxidants that the body makes using this protocol.

Dr. Nathan: Correct.

John: And did you look at homocysteine? Because I know there’s a bunch of, even mainstream doctors now that are giving a lot more credibility to these MTHFR snips than they used to because they see how damaging homocysteine can be. Did you look at that?

Dr. Nathan: Actually we did not. For whatever reason, that wasn’t a part of our study. So I can’t comment on that.

John: Okay. One of the issues that we also wanted to touch on that we haven’t gotten into, I wanna take a minute cause I think the audience our audience is gonna be very interested in hearing from you on is you have these issues, you have mold toxicity, you have impaired methylation and they create this downstream cascade of issues. And one of the things that I seem to be taking away from your book is that the cascade of symptoms is driven by cells called mass cells. And these are basically very temperamental immune cells. They kind of develop a trigger finger and start shooting at everything. Every single thing you put into the body, they start shooting at once mold or Lyme is present in the body. Can you tell our audience about mass cells in, in what you see in your practice about how they can behave when they’re unhappy?

Dr. Nathan: Sure. Mass cells are very important immune cell. They’re found in every tissue of the body, but especially in the tissues that are in contact with the outside world. So for example, there are a lot more mass cells lining the gastrointestinal tract and the sinuses than there are in other body tissues. And what they do is that they monitor the body for infections and toxins and coordinate the immune response with the nervous system to those materials. So if they’re doing their job, nothing much happens. You are exposed to toxins in small quantity. If your body is constitutionally strong, it works fine. But in the patients that I treat and let me emphasize that my patients are typically referrals from other physicians have very, very sensitive and toxic patients that they’ve had trouble working with. So that my patient population is an unusually toxic and sensitive group. And I wanna acknowledge that upfront.

So what happens particularly with mold toxicity and with the infection Bartonella is that toxin and that infection sensitizes these mass cells. So as you are correctly pointing out, they become hypersensitive and hyper reactive. And that means that if you eat or drink anything and they are in an irritated state, they will release what they contain, which is primarily histamine. And patients can have an immediate reaction to histamine, which would include things such as itching, hives, palpitations, anxiety, abdominal pain, diarrhea, shortness of breath, all of those things. If they come on immediately after eating or drinking something is a tip off that your mass cells may be activated and need to be treated.

John: Yeah, and what I hear you saying in the book as well is that because these mass cells are gonna be in flux in terms of how they’re responding to different inputs, you know, theoretically you could put somebody in an environment where the environmental toxicity is such that they’re having an immune system reaction, then they start reacting to a given food. You put them in an environment where there’s less of a reaction, the mass cells quiet down. They have no reaction. And you described this situation where that’s very frustrating for the people that are friends and family members of these people because they say, “Hey, you’re eating tomatoes. I thought you were, you know, super sensitive tomatoes?” What’s the deal here? You know, their food sensitivities are constantly changing. Is that because of the temperament of the mass cells sort of is in flow over time?

Dr. Nathan: Yes. Well, it looks like food allergy, and keep in mind that in food allergy, ultimately histamine is released as well. So you can get a similar reaction but not as fast. But it isn’t a food allergy. So for example, with the example you gave, say tomatoes one day you could eat it and do fine and the next day you can react to it fairly violently. It has to do with the state of reactivity of the mass cell and not to us being put in the body. To emphasize this point, if the mass cells are extremely reactive, people can react to drinking water with a reaction of this nature. And if someone from the outside, I’ve even seen physicians go, “That’s nuts. You can’t react to water.” Well, the truth is yes, you can. And in fact, that is a diagnostic description of what mass cell activation looks like.

John: And to kind of put a bow on this, it seems as though your position in your book ”Toxic” is that at the end of the day, if people have mass cell activation, it’s very typically gonna be caused by these foundational issues of mold and Lyme. And then the downstream effect is that the immune system starts hyper reacting because it’s being irritated by these foundational issues. If you wanted to give a take-home message, is that how you’d summarize it?

Dr. Nathan: Yeah, I think that is a decent summary.

John: So I know, Dr. Nathan, that you’re short on time. It’s been a really good conversation. I think there’s been a lot of pearls of wisdom that you’ve been able to share with us and the new book ”Toxic” is just chockfull of a lot of great information. We appreciate you sharing your Friday morning with us and keep on with the great work.

Dr. Nathan: Okay. Thank you very much, John.

John: Thanks so much. Bye, bye.

Dr. Nathan: Bye, bye.

John: The ”GeneFood” podcast is our attempt to synthesize the latest developments in the fields of genetics, nutrition, and medicine, and offer you practical tips and stories you can use in your own unique health journey. If you enjoy this podcast, you can find more information online at

John O'Connor

John O'Connor is the founder of Gene Food, a nutrigenomic startup helping people all over the world personalize nutrition. John is the host of the Gene Food Podcast and a health coach trained at Duke's Integrative Medicine Program. Read his full bio here.

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  1. Keith Berndtson says:

    Lisa Petrison was the first to bring Dr. Shoemaker’s work to my attention when she loaned me her copy of Mold Warriors in 2007. I was later certified by Ritchie but I had some differences with his approach. I’m a co-founder of ISEAI, a medical society whose mission is to support education, research, and patient care for those who treat patients with environmentally acquired illness. Dr. Nathan was a Board Director for ISEAI but he resigned a couple weeks ago to pursue other projects. I respect Dr. Nathan. I, too, have seen patients with mold related illness improve using limbic system retraining when they are no longer exposed to toxigenic indoor molds. But it cannot work when patients are still exposed. My main concern has to do with research on mice and primates showing that Satratoxin G toxins, produced by Stachybotrys chartarum, not only damage the epithelial cells that line the mucous membranes in the nasal and sinus spaces, they can also damage and kill olfactory sensory neurons: (mice) (primates)
    This can account for severe multiple chemical sensitivities. Ongoing exposure to inhaled mycotoxins, toxic VOCs,, toxic bioaerosols, fragrances, etc., in the face of such cell and tissue damage can explains why some people choose extreme mold avoidance. What’s more, when mycotoxins and other irritants come into contact with hypersensitized olfactory sensory neurons, immediate danger signals are sent to brain nuclei that interfere with short term memory and activate fear and anxiety. To an uneducated observer, the “Get away now!!” response suggests mental illness. If they only knew. Such patients deteriorate quickly if they don’t take aggressive steps to escape ongoing exposure. In fact, it is their highest priority and it would spare rivers of grief if the cause was better understood by friends, family, employers, schools, and the public at large. Limbic retraining gets nowhere with continued exposure. In the context of hypersensitized or dying olfactory sensory neurons, sampling exposures to indoor molds to see how you react is like advising the patient to snort Oxi-Clean.
    Keith Berndtson, MD

  2. Betsy Anderson says:

    This contains a seemingly disingenuous assault on a mold avoiding group that has helped thousands. I have followed that group for years and benefited from personal instruction from a founder. Mr Nathan’s discussion shows failure to understand what avoidance is about. He digresses into talk of “allergies” — which have nothing to do with avoidance — and mold in outside air, also far from the primary or only point. It is now well accepted that the first step in healing from mold is to get away from it. Mr Nathan recognizes that people react to varying degrees. The extent to which people have to get away also varies. Mr Nathan also stresses that our environment is growing ever more toxic, and that it is important that people pay attention to how their body reacts to toxic substances. He explains how some may have multiple chemical sensitivities. At the core of mold avoidance, is helping people learn how to recognize toxic substances, and to observe how their body reacts to different substances. That is, exactly what Mr Nathan says should be done — to learn to discern what affects a particular individual and what they may need to avoid. The approach also encourages detox to help heal. For some reason however Mr Nathan engages in a practice he himself identifies as common and unfair to the moldsick, implying the main problem is in people’s heads and dismissing an entire category of mold avoiders and its founders as “paranoid” and “overwhelmed by fear .”

    • Betsy, while I disagree that Dr. Nathan’s comments amounted to an assault, you make some good points. Thank you for the comments. I am going to try to get on a mold avoidance author or doctor for the alternative viewpoint.

      • Concerned citizen says:

        An alternative viewpoint sounds like a great idea. I would recommend you bring on Lisa Petrison or Erik Johnson. The medical community has been very slow to learn the intricacies of mold avoidance simply because that process does not make them money. Another option might be Mary Ackerly. But truly very few doctors have tried mold avoidance and so very few are able to speak to it in any detailed way.

  3. Lisa Petrison says:

    Hi Dr. O’Connor,

    Some folks told me that I had been mentioned here in the comments and that you had said you were waiting for a response from me.

    I summarized my perspective on the so-called “brain retraining” programs in this article a few weeks ago (Point #18), and so if people are interested in what I have to say on this topic, they can start by reading that.

    But if people think that the Nathan/Hopper approach would be better for them than some other approach, then that is what they should pursue.

    I am not making any money at all off of anything that I am doing with regard to chronic illness issues, and so my only dog in this race is that I would like for the illness to be better understood and people to be able to regain as happy and meaningful of lives as they can.

    If the Nathan/Hopper approach can give that to them, as Dr. Nathan seems to be promising here that it will, then that would be great. I wish them all the best of luck with that.

    I hope that this answers your question.

    Best regards,

    Lisa Petrison, Ph.D.
    Executive Director
    Paradigm Change/Mold Avoiders

  4. Jennifer JP says:

    I agree with Tami. The comments concerning mold avoidance are highly offensive and false, as mold avoidance is the ONLY “treatment” that has helped my entire family. Unless we are all just paranoid…

  5. Tami zigabarra says:

    I am offended at the comment of Dr. Neil Nathan at the suggestion that the Mold avoiders are in a state of “paranoia” – i assure you the money and time spent on these “mold doctors” has done nothing for my daughters health the way mold avoidance has- and i also assure you we do not live in paranoia and in fact seek out moldy environments to learn how to sense it so that my daughter learns how to decontaminate. This comment is completely ignorant and has me losing respect for Dr neil nathan as he clearly has not lived the mold world as some of us have!

    • Hey Tami,

      I knew that would be a controversial point. Please don’t be offended, Dr. Nathan was simply stating his opinion, and it’s an opinion based on over 40 years of clinical experience. Having said that, I have invited on the Executive Director of Paradigm Change for the perspective of the Locations Effect groups. I have yet to receive a reply.

      • Concerned citizen says:

        Correction: Dr. Nathan’s opinion about mold is *not* based on over 40 years of clinical experience healing patients affected by mold. Sadly, he just jumped on the mold bandwagon in the last few years and almost half of what he says and writes about the topic shows an embarrassing lack of understanding of the topic that he now claims to be an expert on.

        Frankly, as a patient with biotoxin/mold illness and a doctorate myself, it is clear to me that Dr. Nathan he has no idea what he’s talking about. Some of what he says it true, but the remaining 40% of the advice he offers is extremely harmful to the progress made toward finding healing paths for patients with biotoxin illness in the past 22 years, and would be disastrous for patients or their doctors to attempt to follow. How is a newly sick patient or their doctor supposed to sort through the garbage to find the bits of truth in his book or this interview? I recommend that they don’t bother, and instead turn to an actual expert on mold illness, which you can find a link to below.

        Dr. Ritchie Shoemaker ( was the first doctor to pay attention to mold and biotoxin illness starting in 1997, which was only 22 years ago, when Dr. Nathan was still nowhere to be found. Dr. Shoemaker was completely on his own for years, but has emerged as essentially the founder and discoverer of mold illness, and he has generously trained and certified many other doctors.

        Sadly, now that mold illness is a major topic of discussion a bunch of opportunist doctors are now coming out of the wood work claiming to be experts without even having taken that basic course. Dr. Nathan is one of them – he has worked with mold illness patients for about the past decade and some have cited him as helping them, however he has never completed Dr. Shoemaker’s training course (which many other doctors have done as a first step to learn the basic principles of biotoxin illness).

        What really leaves a bad taste in my mouth is that Dr. Nathan is well-known among the patient community for turning away some of the most ill patients from his practice (two people I know personally went to him at their most desperate and were turned away for being “too complicated), and yet his website claims, “I am now primarily seeing referrals from physicians who have studied this new field of functional medicine, and who have tried many of the interventions discussed in these books. They are helping most of those patients, but the ones who are not responding, the outliers, are being referred to us in ever-increasing numbers.” (

        His recent book and interviews with him are filled with equally perplexing contradictions, which makes him an unreliable and unqualified source of information about treating the most sensitive patients. I do not recommend that anyone treat Dr. Nathan as an expert. I do not recommend to the patients or doctors I know that they use Dr. Nathan as a source of information or treatment. As far as I can tell he is a snake oil salesman whose patients occasionally improve by chance.

        If you’re looking for guidance on mold illness, I honestly feel that the best resource out there is not from a doctor but a fellow traveler, Lisa Petrison, who took time to reply to a comment above. She is personally responsible, along with other pioneers like Erik Johnson, for tens of thousands of patients (and often their families as well) finding significant improvement in their lives. She does this not to make money like many of these doctors suddenly claiming to be mold experts seem to be doing, but because she believes in a world in which people are not having to fall victim to the preventable but shockingly pervasive illness she has personally managed to crawl back from.

        If you think you or your patients may be sick from mold, the best place to start is the website she has created that has helped so many before you: Her website also features many practitioners who work with patients with mold illness, available to see here:

        The bottom line is that anyone who preys on the most sick will always receive backlash like this comment. Those of us who have been injured by toxic mold want nothing more than accurate information so that we can get well and try to shift society to prevent more people falling ill.

      • Tami zigabarra says:

        I would suggest speaking to the original prototype for cfs/me that has relentlessly tried to get researchers to pay attention to the cause of such illnesses Erik Johnson . He is the very person that created and taught so many how to get well and is currently providing tours to teach others how to do this successfully – my daughter is getting well because of him. If you would like to interview with him you may do so by contacting me at my email. Thank you for being open to provide the other side of this very hot topic!

  6. Steve Simpson says:

    I do nutrigenomic testing and look at the Snp’s of the MTRR664A and MTRR66G, as well as TCN1 and TCN2, and finally GIF. I would like to learn why you feel hydroxo is a better form. I have not learned about that.

    • Steve,

      This is not necessarily our position at Gene Food, it is the opinion of Dr. Nathan. I will follow up and see if he has some additional info on this as we are getting a bunch of comments / questions on this issue. Thanks for the comments.

    • Markus says:

      I think it varies from person to person depending on a combination of genetic variants in the methylation cycle, in addition to other contributing factors and/or potential environmental insults.

  7. Steve Simpson says:

    Why does the methylation pathway convert the other forms of cobalamine into methyl before use if hydroxycobalamine is preferred?

  8. Markus says:

    Thank you for another great episode! Short and to the point.

    I’m currently dealing with mold toxicity and can totally relate to the chemical sensitivity issues. In addition, I have also experienced reactions to different supplements (especially methylated B-vitamins), which has made me more conscious about what I use nowadays.

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