Mycotoxins and Mold One of the Biggest Root Triggers for Mast Cell Activation | Histamine Intolerance

Mycotoxins and Mold: One of the Biggest Root Triggers for Mast Cell Activation | Histamine Intolerance

It took me nearly 2 decades to figure out my biggest root triggers for my own Mast Cell Activation and Histamine Intolerance. I have had all the Root Triggers I discuss here. But Mold Toxicity has been one of the worst for me.

And I see it in about 80% of those in my practice who have Mast Cell Activation Syndrome and Histamine Intolerance.

Mold Toxins are behind most of these symptoms I see:

    • ice pick” or “lightning bolt” pains
    • supplement sensitivities
    • food sensitivities like salicylate intolerance
    • dry eyes or blurred vision
    • difficulty regulating body temperature (too hot or too cold)
    • a higher number of static shocks
    • muscle cramps from electrolyte disturbances
    • digestive issues
    • joint pain
    • cognitive issues, including mood swings
    • numbness and tingling
    • inability to detox
    • weakened immune system
    • catching every infection
    • slow or difficulty healing

I myself developed mold sensitivity as a child

When I was seven years old, my family moved into an old farmhouse in the country. At that time, my health slowly started to go downhill. 

We wouldn’t know until later that that farmhouse was full of toxic mold.

Then I had more mold exposure as an adult. 

I became so ill, I was bedridden. And you may know already – I had to use a cane to walk by the time I was 28 years old.

The health issues started as difficulty paying attention in school and a weakened immune system. Because my immune system was compromised, I ended up with Lyme disease and other co-infections. 

I also had a brain injury at age 9. And the mold toxicity prevented me from being able to heal. 

Mold toxicity can cause a huge number of seemingly random symptoms

Some of the ones I had were: 

  • bizzare and excruciating “ice pick” or “lightning bolt” pains 
  • really dry eyes that weren’t helped by eye drops
  • major blood sugar issues
  • elevated thyroid antibodies
  • a host of other health issues

By the time I was 12, if I didn’t eat breakfast right away, I would black out and feel like I was going to pass out.

By the time I reached by early 20s, I had to eat every two hours in order to keep my blood sugar steady. This was because of the mold’s effect on my pancreas.

Have you ever dealt with that?

The longer the mold stayed in my body, the more toxins it produced. The mold had actually colonized my body, just like what can happen with bacterial or viral infections. But a mold infection is a type of fungal infection.

Next, let’s look at what mold toxins are…

What Are Mold Toxins and How Do They Affect Mast Cell Activation and Histamine Intolerance?

The toxins produced by mold in your body are called “mycotoxins.” “Myco” comes from the Greek word for “fungus.”

As the mycotoxins build up in your body, you can develop more and more health issues. 

There are a number of different types of mold toxins or mycotoxins. These are some of the major categories: 

  • Trichothecenes — Especially toxic to the body. Black mold produces several of these. This toxin can come from Fusarium and Stachybotrys molds and others. This category includes around 170 different toxins, which grow on plant material or soil. They can cause bleeding disorders and nervous system issues. They affect the skin, GI tract, breathing, lungs, and sinuses. They can damage blood producing cells.
  • Ochratoxins — One of the most common mycotoxins in food. Includes aspergillus and penicillium species. Also common in water-damaged homes and in heating ducts. It’s toxic to the immune system, liver, and kidneys. It can also be cancer-causing. They can increase UTI issues.
  • Gliotoxins — Comes from Aspergillus and Candida. This is the most common mold toxin causing disease in humans. It can significantly affect the immune system. It can also cause problems with the lungs, brain, and bone marrow. It has been linked to brain and lung tumors.
  • Aflatoxins — Commonly found in plant foods like peanuts. Meat or dairy from animals who have eaten aflatoxin-contaminated feed may also contain this mycotoxin. Aflatoxin exposure has been linked to kidney problems and liver issues, including jaundice and hepatitis. It has also been associated with lung cancers.
  • Mycophenolic acid — Produced by the Penicillium mold. It suppresses the immune system and increases a person’s risk for infections like Clostridia and Candida. Exposure during pregnancy may lead to birth defects or miscarriage.
  • Citrinin — Produced by a few types of mold like Aspergillus and Penicillium. Exposure suppresses the immune system. It may also cause damage to the kidneys. Animal studies indicate it could cause cancer.

You can see how dangerous these mycotoxins are for the body in general. 

They also act as a trigger for Mast Cell Activation Syndrome and Histamine Intolerance. This is how:

  • They dysregulate and dampen the immune response
  • They disrupt hormones
  • They significantly disrupt the nervous system
  • They clog up detox pathways

Each of these areas affects the others because each of these body systems is affected by mold and because each affects the others, mold toxins can create complex problems in the body. 

The body also starts to enter something called the “Cell Danger Response.” This is where a bunch of pathways in the body start to shut down to prevent the mold from spreading. 

The body moves from “fight or flight” to FREEZE. 

As a result, you may have been told you have methylation issues, or sulfur issues, or mitochondria issues. Everything’s just been shut down. The body is trying to protect itself.

These changes happen in the body:

  • Vitamin D activation reduced
  • Glutathione production reduced
  • Methylation pathway dysfunction
  • Increases of histamine and mast cell activation
  • Dysregulation of the heme pathway
  • Decrease of serotonin and melatonin production
  • Reductions in heavy metal clearance
  • Disruptions to the GI tract
  • Cell wall hardens 

One of the major problems happening in healthcare is addressing these upstream issues before addressing the ROOT Factors.

Some practitioners will want to jump in and help you with methylation or processing sulfur, or clearing metals. However, if you have Mast Cell Activation Syndrome or Histamine Intolerance, you might actually get worse!

It’s important to address the root trigger (mold in this case) before tinkering with these pathways.

These changes from the Cell Danger Response are ways the body keeps pathogens like mold from spreading.

If you start working upstream on fixing methylation or taking a lot of mast cell stabilizing medications, the Mold infection now has an easier time spreading.

And this just causes the mast cells to become more imbalanced and to produce more and more inflammation. 

And then you get more and more Mast Cell symptoms. Examples include:

    • Respiratory issues like sinusitis, bronchitis, coughs, aggravation of asthma
    • Neurological issues like sleep problems, brain fog, headaches, fatigue, and nausea
    • More food sensitivities
    • Worse GI issues

Exactly what you don’t want.

How do you Get Mold Toxicity?

I’ve talked a lot about other triggers for Mast Cell Activation Syndrome and Histamine Intolerance in the past. However, mold toxicity is a trigger that we need to focus on much more.

I didn’t even realize until a couple years ago how big of a problem this is.

But first, you need to now…how do you even get mold toxicity?

The main way is through environmental exposure. This could be from living in a moldy house, working in a moldy building, or even attending a moldy school.

Why are buildings so moldy these days? Well, partly because building codes changed in the 1970s. 

During that time, efforts were made to make buildings more energy-efficient. To accomplish this, buildings were constructed to be more air-tight. 

The changes were great for reducing energy use and energy cost. However, with all the cracks and crevices sealed, condensation and moisture were also sealed in the walls and in the home. 

This increased the tendency for mold to grow. 

Other potential contributing factors or sources of mold exposure include:

    • Living in a humid area (the coast, the South… anywhere besides the desert)
    • Leaking pipes (even very slow leaks of a drop a minute or so)
    • Air conditioning units (especially window units and evaporative cooling aka “swamp coolers”)
    • Humidifiers attached to furnaces
    • Water exposure in a car (windows left down)

And children are much more susceptible to mold toxicity. We’ve seen a big uptick in the past 20 years in young kids with mold toxin issues.

Now, people also ask me about mold toxins in foods.

It’s not as common to get mold poisoning from food, particularly in Western countries. 

A few hundred years ago, mold poisoning through food was more common. 

In the 1500s and 1600s, a fungus called ergot was found in rye. When people ate the contaminated rye, they would have brain symptoms like hallucinations, convulsions, and irrational behavior. 

In fact, some people got charged with being witches –simply from the effects of mold poisoning.

Our foods are now tested thoroughly for mold. However, it’s possible that something could occasionally slip through testing. Additionally, if you’re really mold-sensitive, you could react to certain foods that have trace amounts of mold. 

Some of the foods to look out for include:

  • peanuts
  • coffee
  • grains
  • nuts
  • beer and wine
  • hard cheeses

But in general, Western foods are going to be pretty safe.

Keep in mind that if you are traveling to less developed countries, you’ll have to be much more careful. Their mycotoxin food testing is not going to be as accurate or consistent.

Next, let’s look at how to find out whether you have mold toxicity.

How do you Test for Mold Toxicity if you have Mast Cell Activation or Histamine Intolerance?

We can test for mold toxins in a number of different ways. However, the two main types that tend to be used are blood testing and urine testing.

The blood testing will look for whether you have antibodies to mold toxins in your bloodstream. This is great for determining whether you have current exposure to mold. 

It shows the immune system’s response to the mold species and toxins. It can be helpful if urine testing is negative.

Urine testing shows what levels of mold toxins are currently being excreted by the body.

Urine gives us an idea of where to start for detoxing the mold. Because you can start with supports targeted at the highest levels of mold toxins.  And the urine testing can help with how the supports may need to be increased or decreased overtime. 

Unfortunately, there’s no single panel that is excellent at detecting all the mold markers in one test.

For that reason, I use two urine lab tests side by side: The Great Plains Mycotoxin test and the RealTime Mycotoxin test.

  • The Great Plains Mycotoxin testing method seems to be better at detecting ochratoxins, mycophenolic acid, and citrinin. 
  • The RealTime Mycotoxin test is more sensitive for trichothecenes, gliotoxins, and aflatoxins.

The two tests complement each other. So, when they are used together, we can get a more complete picture of the molds and mycotoxins affecting the body. 

Let’s look at both of these tests in more detail.

Great Plains Mycotoxin Test

Here’s a sample of a Great Plains Mycotoxin test:

Mycotoxins and Mold One of the Biggest Root Triggers for Mast Cell Activation | Histamine Intolerance

Here is where you can get the test:

>>>>Order Great Plains Mycotoxin (US) here 

>>>>Order Great Plains Mycotoxin (Canada) here

This test checks for 11 different types of mycotoxins coming from 40 species of mold. The mycotoxins tested include the following:

Mold Toxins Being Tested:

  • Aflatoxin M1 (AFM1)
  • Ochratoxin A (OTA)
  • Sterigmatocystin (STG)
  • Roridin E
  • Verrucarin A
  • Enniatin B1
  • Zearalenone
  • Gliotoxin
  • Mycophenolic Acid
  • Citrinin
  • Chaetoglobosin A

Fasting is not required and the turnaround time is usually 21 days. 

RealTime Mycotoxin Panel

Here’s a sample of a RealTime Mycotoxin Panel:

Realtime Sample Mycotoxin Test Mast Cell 360

Here’s where you can get the test:

>>>>>Order the RealTime Mycotoxin Panel here (Scroll down towards the bottom)

This test checks for the following mold toxins:

  • Ochratoxins
  • Trichothecenes
    • Satratoxin G
    • Satratoxin H
    • Isosatratoxin F
    • Roridin A
    • Roridin E
    • Roridin H
    • Roridin L-2
    • Verrucarin A
    • Verrucarin J
  • Aflatoxins: 
    • Aflatoxin B1
    • Aflatoxin B2
    • Aflatoxin G1
    • Aflatoxin G2
  • Gliotoxin 

Fasting is not required and the turnaround time is usually 7-10 business days.

How to Provoke a Mycotoxin Test if you have Mast Cell Activation or Histamine Intolerance

Now, to make sure the testing is accurate, it’s helpful to gently provoke the mold detox pathways.

Again, I really want to emphasize, this MUST be done GENTLY.

With Mast Cell Activation Syndrome and Histamine Intolerance, we never want to push detox pathways too hard because we can trigger a major flare.

However, we can start to gently provoke.

The reason we need to provoke is because mold toxins tend to be stored in our tissues –particularly, our fat tissues. These mold toxins are not good for the body. So, the body doesn’t want the mold toxins circulating in the urine. That’s why they’re safely stored away.

But, we can get more reliable results by gently provoking by either sweating (if tolerated) or by taking some glutathione. Or both if possible.

But, you don’t want to do anything that you know triggers you. So, if you know that sweating is a trigger for you, then skip that part. If you know you don’t do well on glutathione, then skip that part.

If you could do both, that’s ideal. But you have to do what’s tolerable for your body.

Here are guidelines I use for provocation for Mycotoxin testing. But you have to look at it and see what would work for you. Be sure to discuss with your healthcare provider.

MycoToxin Provocation Guidelines

  1. Be sure to stop taking all binders before you do the urine collection

Binders are things like Activated Charcoal, GI Detox, Bentonite Clay, Humic/Fulvic Acid, Diatomaceous Earth, Chlorella, etc.

  • Add S-Acetyl-Glutathione. I use this kind:

  • Start with a tiny amount, like ⅛ tablet. See if you can gradually increase to 100mg 1x/day, then if tolerated 100mg 2x/day. 

Find the amount you tolerate without an increase in symptoms. 

The maximum would be 500mg 2x/day. Very few people with Mast Cell Activation can go that high. And it is NOT necessary at all to go that high. Just go to what you tolerate.

  • Continue the amount of S-Acetyl-Glutathione for 6 days, then collect next morning urine.
  • If you feel worse at any point – achiness, fatigue, brain fog or have any increase in symptoms not explained by something else, stop the glutathione and collect first morning urine the next day.

Many people ask me about Reduced Glutathione. It has been shown in research to not be as well absorbed. Liposomal Glutathione may be ok.

Or Glutathione IV (but only if you know you tolerate it – many with Mast Cell Activation don’t tolerate Glutathione IVs)

  1. If you can tolerate heat, then you can do Sauna (10-30 minutes) or hot bath (30 minutes) to sweat. If tolerated, sweat 2 to 3 times throughout the week you are on glutathione. And your sweating would be the day before collection. Then collect your first morning urine.

If you feel worse- achiness, fatigue, brain fog or any increase in symptoms not explained by something else, stop and collect first morning urine the next day.

What if your Urine Tests are Negative? 

So, you may find that you are certain you have mold toxicity. But your urine tests are negative. 

If you’ve had mold exposure, the urine tests can be negative if your body can’t excrete them yet. This often happens in people who are really sick.

When this happens, then I turn to the blood testing. The best lab for the Mycotoxin Blood Testing is MyMycoLab.

It tests for 24 IgE and IgG antibodies to different mold toxins.

Bottom Line on Mold Toxins and Mast Cell Activation Syndrome

We covered a lot of ground in this post:

  • How mold toxicity is a MAJOR trigger of Mast Cell Activation Syndrome and Histamine Intolerance
  • Symptoms associated with mold toxicity
  • How you can get mold toxicity
  • What are mold toxins
  • How to test for Mold Toxins

Read about how to address Mold Toxins here: Addressing Mold Toxins when you have Mast Cell Activation Syndrome or Histamine Intolerance

Have you had Mold Toxicity? If so, did it affect your Mast Cell Activation or Histamine Intolerance?

Download Free Mast Cell 360 Guide for MCAS button

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References on Mold Toxins for those with Mast Cell Activation and Histamine Intolerance

Anyanwu, E. C., Campbell, A. W., & Vojdani, A. (2003). Neurophysiological Effects of Chronic Indoor Environmental Toxic Mold Exposure on Children. The Scientific World JOURNAL, 3, 281–290.

Bankova, L. G. et al.  (2016). The leukotriene E4 receptor, GPR99 mediates mast cell-dependent mucosal responses to the mold allergen, alternaria alternata. Journal of Allergy and Clinical Immunology. 137(2).

Kritas, S. K., Gallenga, C. E., D Ovidio, C., Ronconi, G., Caraffa, A. l., Toniato, E., Lauritano, D., & Conti, P. (2018). Impact of mold on mast cell-cytokine immune response. Journal of biological regulators and homeostatic agents, 32(4), 763–768.

Nathan, N.  (2018). Category: Mast Cell Activation. Retrieved from:

Nathan, N. (2020). Mold & mycotoxins: Effective testing & treatment. 

Nathan, N. (2018) Evaluation & treatment of mold toxicity with the use of mycotoxin assays.

Nathan, N. (2018). Toxic: Heal your body from mold toxicity, lyme disease, multiple chemical sensitivities, and chronic environmental illness. Victory Belt Publishing. 

Naviaux, R. K. (2014). Metabolic features of the cell danger response. Mitochondrion, 16, 7–17.


  1. Melanie

    I listed to your talk about mold and you were going to link the test to see if there is a mold colony in the gut but I don’t see that

  2. mira lire

    Beth – you said you were going to post a link to ur favorite dehumidifier, but I don’t know where to find that. Thx for ur last fb live presentation, looking 4ward to the next.

  3. Cindy

    If you have mast cell activation due to mold , and you do not recommend medication for MCAS how do you fix this if you are out of mold and still have brain fog?

    1. Beth O'Hara

      Hi Cindy,
      I’m not against medication for MCAS. I do want people to know the problems of long term use and not addressing the root causes. Keep an eye on your inbox – our blog post on how to structure mold protocols will come out soon.

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