49. Mold, Lyme and Bartonella with Dr. Neil Nathan (part 1)
How our cells and nervous system respond.

Dr. Neil Nathan is a physician and author, and is a Founding Diplomate of the American Board of Integrative Holistic Medicine, and the International Society for Environmentally Acquired Illness (ISEAI). He has practiced medicine for over 50 years including 30 years treating patients with chronic complex illnesses, and 20 years treating patients with Lyme disease. He has written several several books about chronic illness, mold toxicity and other environmental illnesses, Lyme and energetic diagnosis. He joins us from Northern California to explore the foundations of mold toxicity, Lyme disease and other infections, and the impact they have on our cells and our nervous system. This podcast is part one of a two part interview.
Medical misfits
Throughout his career, Dr. Nathan has observed that certain illnesses don’t fit neatly into medical models. While working at a pain management center in the 1980’s, Dr. Nathan and his colleagues saw many patients with what was once called fibrositis, and is now known as Fibromyalgia. Because diseases such as Chronic Fatigue Syndrome (CFS) and Fibromyalgia were poorly understood, many of these patients were referred to psychiatrists, and given medications that didn’t work.
Better understanding, better treatment
With better understanding of the biochemistry of Fibromyalgia and CFS, better treatments were discovered. Over time, though, those treatments became less effective, leading doctors to explore other contributing factors such as Lyme disease. Many patients who weren’t responding to treatments for Lyme disease were also found to have mold toxicity. With the increase in patients presenting with these problems, Dr. Nathan decided to take matters into his own hands and learn all he could about Lyme disease and later, mold toxicity.
“We started seeing, back in the 80’s, this odd condition that we called fibrositis, which we now call fibromyalgia, and we began to see an amazing amount of people with fibromyalgia and chronic fatigue…initially what happens in medicine when you get patients who don’t fit whatever model we don’t have, it’s in their head, so these patients were all referred to psychiatrists, and they got therapy and they got medication, and it didn’t work…there’s physical causes for this that we’re not understanding.”
Dr. Neil Nathan
Responding to mold exposure
Dr. Nathan explains that chronic illness is often a result of inflammatory processes that occur when the body is exposed to toxins or infections it can’t regulate. One of the environmental toxins he sees most commonly is mold, and the most common infection he sees is Lyme. Although there is a genetic component to who may become ill from mold exposure, Dr. Nathan points out that there are other contributing factors. He notes that when teachers and students are exposed to mold in their school, only some of them experience symptoms of mold toxicity.
Another “great masquerader”
Dr. Nathan sees mold toxicity as an epidemic that nobody is really talking about, and points out that it currently affects at least 10 million people in the US. He explains that, like Lyme, mold can be understood as the “great masquerader.” Also like Lyme, an individual’s inflammatory response may be different depending on their genetics and biochemistry, and can affect virtually any system in the body. Symptoms can vary and include fatigue, brain fog, cognitive impairment, anxiety or depression, breathing or sinus problems, gastrointestinal issues, pain, autoimmune diseases.
“Some patients who had Lyme disease weren’t responding to our treatments either, and they had mold toxicity…it became increasingly obvious that we were living in an epidemic of Lyme disease and mold toxicity, and that I had to get on really quickly to understand it, and understand how to treat it if I’m going to help these folks.”
Dr. Neil Nathan
Diagnosing mold toxicity
Dr. Nathan emphasizes the importance of understanding mold toxicity as a diagnosis, and begins his assessment by inquiring about mold exposures a patient may have now or have had at any time in the past. Patients may not recall seeing mold, or having symptoms at the time of exposure. Some patients may simply recall that they lived in a basement that had a funny smell. To properly diagnose mold toxicity, Dr. Nathan recommends a mycotoxin urine test which will indicate which (of many) mold toxins patients may have in their body.
“Mold toxicity weakens the immune system and predisposes to Lyme. Lyme weakens the immune system and predisposes to mold. There are an amazing percentage of people who have both. It’s not rare.”
Dr. Neil Nathan
Mold treatment basics
Treatment for mold toxicity starts with eliminating current mold exposure. Dr. Nathan explains that mold toxicity is very treatable, but only if a patient is not currently being exposed to mold. This may require moving to a different environment, or having a professional remediate the mold problem. He understands how difficult this may be for many patients, and notes that mold is common in many areas of the world. The second part of treatment involves taking binders that remove specific toxins. Patients who have developed subsequent fungal infections in their sinuses or gastrointestinal tract may also require antifungal treatment and biofilm agents.
“Mold toxicity is one of the biggest epidemics that hasn’t been talked about, that we understand so far. It’s estimated in the States that at least 10 million people right now have some degree of mold toxicity…part of the problem…is to recognize the myriad symptoms that mold toxicity can present with. Like Lyme, mold is the great masquerader. Like Lyme, the inflammation which triggers it can manifest in people very differently based on their genetics and biochemistry, so it can show up in any system of the body.”
Dr. Neil Nathan
Treat mold first
Dr. Nathan explains that his approach to patients is often like peeling the layers of an onion. Because there are many symptoms common to mold, Lyme and Bartonella, he again recommends a urine mycotoxin test, and if necessary, to treat mold first. He has found that patients respond much better to chronic Lyme or Bartonella treatment if their mold issue is addressed first, and points out that this helps protect their microbiome as well.
“My take home message is, mold toxicity is very treatable, but not if you stay in a moldy environment…for many people this is financially, socially and in many ways, very difficult to leave this environment.”
Dr. Neil Nathan
The mold and Lyme connection
One of the big takeaways Dr. Nathan has for physicians and patients, is for them to consider looking for mold toxicity, especially when patients are not responding to treatments for Lyme disease and co-infections. He notes that, when patients have one of these issues, they are often predisposed to the other. One of the leading Lyme physicians in the US, Dr. Richard Horowitz, found that 70% of his Lyme patients were also dealing with mold issues.
Limbic, vagal and mast cell responses
While chronic illness can affect virtually any system in the body, Dr. Nathan explains that its impact on the central nervous system is profound. He has found that if the issues of limbic dysfunction, vagal nerve dysfunction and mast cell activation are not addressed, patients often do not get well. He sees mast cell activation in about 70% of his patients with mold toxicity, and even higher incidence of limbic and vagal nerve dysfunction.
“One of my take home messages is, if you have Lyme, please ask your physician to check for mold, you don’t want to miss that.”
Dr. Neil Nathan
Addressing limbic system dysfunction
Dr. Nathan explains that the limbic system regulates emotion and sensitivity, as well as cognition, energy and pain response. Some symptoms of limbic dysfunction are anxiety, depression, and sensitivity to things such as light, sound, electromagnetic frequency or chemicals. He has found that patients often do not respond to other treatments until their limbic system dysfunction has been addressed, and refers patients to limbic retraining programs such as the Dynamic Neural Retraining System (DNRS) created by Annie Hopper.
The cell danger response
Dr. Nathan explains a model of chronic illness developed by Dr. Bob Naviaux called the cell danger response (CDR). When our bodies are threatened by a toxin, infection or stress, our entire body is affected on a cellular level, and our cells go into survival mode. He points out that physicians can measure levels of vitamin B6, zinc, but notes that mitochondrial dysfunction is a consequence of the CDR and not a diagnosis. He reiterates the importance of looking for the cause, and that cause is related to the issue of safety.
It’s all about safety
The limbic, vagal and mast cell systems are all about safety, and as Dr. Nathan explains, will shut down processes in the body in order to protect it. These systems are constantly on the lookout, internally and externally, for signs of danger, and over time can also become hypervigilant. He emphasizes the importance of treating limbic, vagal and mast cell activation issues, and then toxins and infections, in order for patients to get better.
“Limbic, vagal and mast cell systems are all about safety…as they shut down in order to protect the body, not hurt it, they’ve become, over time, increasingly over-sensitive, over-reactive, hypervigilant.”
Dr. Neil Nathan
Understanding methylation
Dr. Nathan explains that during the cell danger response, cells stop methylating. Dr. Nathan describes methylation as a major biochemical process involving hundreds of chemicals in the body. He explains that when cells encounter viruses, methylation shuts down to prevent the virus from replicating. It is a protective response, and reverses when it is safe to do so. He cautions against using supplements to counteract this decrease in methylation without addressing the cause of decreased methylation. He also explains that during the cell danger response, the body is not able to clear toxins such as heavy metals, and that by addressing the CDR, the body is better able to rid itself of these toxins.
Stay tuned for part two!
Thank you Dr. Nathan for joining us to talk about mold, Lyme and the cellular and nervous system! Keep an eye out for part two of this podcast, where Dr. Nathan further explores Bartonella, treating chronic illness and directs us to resources where listeners can learn even more!