Why Chronic or Sudden Digestive Symptoms May Indicate Mold Exposure

by Dr. Koji Aoki DC

According to the NIH (National Institutes of Health), there is an urgent need for “remediating water damage in home” as there is “strong evidence that indoor mold can contribute to asthma development” (1, 2). Because high indoor mold counts cause a large influx of mold spores into the breathing space of the occupants with the respiratory passages like sinuses, throat, and lungs, being the main entry points, it makes sense that the respiratory system itself could be compromised. However, a significant number of patients suffering from Biotoxin Illness due to mold exposure also report troublesome gastrointestinal issues. Reported symptoms include, but are not limited to:

  • Abdominal Pain
  • Constipation
  • Multiple Food Sensitivities
  • Gastro-esophageal Reflux Disease (GERD)
  • Weight Loss or Weight Gain
  • Loose Stools
  • Nausea
  • Poor Appetite

How Does Mold Affect Organs Far from the Lungs?

One reason is that mold molecules are amphipathic, meaning they can dissolve in both water (hydrophilic) and lipids (hydrophobic). This property allows mold to move through any body tissue, causing a wide range of toxic symptoms. When mycotoxins (mold toxins) enter the body through inhalation, touch, ingestion, or from existing mold colonies in the sinuses or digestive tract; they bind to cell membranes and disrupt various cellular functions. This triggers an inflammatory cascade, activating the innate immune system, releasing inflammatory cytokines, and interfering with neuropeptides produced in the hypothalamus (3). Disruptions to these brain chemicals cause many systemic effects (4):

  • Chronic Sinus Congestion
  • Photophobia (Light Sensitivity)
  • Headaches
  • Muscle Aches and Cramps
  • Disequilibrium and Dizziness
  • Fatigue/Weakness
  • Joint Pain w/ Morning Stiffness
  • Coughing, Chest Pain
  • Shortness of Breath
  • Numbness and Tingling
  • Sensitivity to Electrical Shocks
  • Cognitive Impairment
  • Acne
  • Rashes/Eczema
  • Frequent Urination

The Insidious Effects of Mold on Digestive Health

As stated at the beginning of this article, one body system that mold exposure often becomes problematic for is the digestive tract. Mycotoxins can wage war against beneficial gut bacteria, allowing harmful bacteria to dominate (3). This imbalance can result in constipation, diarrhea, abdominal pain, and leaky gut syndrome. In leaky gut, undigested food particles or toxins leak into the bloodstream from the gut, causing widespread issues. On the other hand, a balanced gut microbiome, rich in beneficial microbes, can protect against mold-related digestive problems and mycotoxins.

Mold and Small Intestinal Bacterial Overgrowth (SIBO)

Mold can weaken gut immunity, opening the door to gut infections. Toxins from black mold are linked to a drop in IL-8 levels in the intestine, which helps remove pathogens. This can lead to SIBO, where there’s an abnormal rise in bacterial numbers in the small intestine. Mycotoxins make the small intestine more vulnerable to this type of infection, complicating the effectiveness of treatment for SIBO.

Structural and Functional Damage to the Gut by Mycotoxins

Mycotoxins impair gut health by disrupting the balance of gut bacteria, increasing intestinal permeability, interfering with nutrient absorption, and increasing susceptibility to gut infections. They can alter gut microbiota, promote the growth of harmful bacteria, and lead to leaky gut syndrome by weakening the intestinal epithelium. This increased permeability allows pathogens, toxins, and foreign antigens to enter the bloodstream. Mycotoxins also damage intestinal villi, reducing the surface area available for nutrient absorption, leading to malnutrition and weight loss. Additionally, they can induce oxidative damage in the GI tract by increasing the production of reactive oxygen species (ROS).

Exacerbating Factors

Several factors can worsen the harmful effects of mycotoxins on the gut, such as poor diet (i.e. Standard American Diet), antibiotic use, stress, exposure to other environmental toxins, and genetic background.

A Standard American Diet high in grains, conventional dairy, and processed foods will increase exposure to mycotoxins from food and can contribute to systemic inflammation. This dampens the ability for the immune system to fight off the mold and other infections that might arise.

Antibiotics and stress disrupt gut flora, reducing the microbiome’s capacity to detoxify mycotoxins.

Exposure to other environmental toxins like endocrine disruptors (phthalates, parabens, bisphenol A), fluoride, heavy metals (mercury, lead, arsenic), glyphosate and pesticides further increases GI tract toxicity.

For those with SIBO or IBS, mold exposure might exacerbate their condition. A healthy gut microbiota can metabolize some ingested mycotoxins, but mycotoxins can also alter the microbiota, reducing its natural detoxification capacity. Patients with pre-existing gut issues may be more severely impacted by mycotoxin exposure due to changes in their gut bacteria.

Knowledge is Key

Understanding the complex relationship between mold exposure and gastrointestinal health is crucial for both prevention and treatment. If you suspect mold exposure is affecting your digestive health, here is what you can do:

  1. Test Your Home – Avoiding the mold exposure is the first and upmost important part of healing. Use E3 Mold Plates or the ERMI test. We also use the EC3 fogger in the office and in my home to keep the environment clean. Make sure that you are having 2-3 bowel movements/day! I know that seems a lot but that is a sign of a healthy functioning gastrointestinal system.
  2. Support Detox and Drainage – Use sequestering agents like Carbonized Bamboo, Fulvic and Humic acid, Activated Charcoal, and even prescriptions like Cholestyramine or Colesevelam (Welchol). You also want to support your liver’s biotransformation with Glutathione and Milk Thistle.
  3. Clean Up Your Diet – Avoid the Standard American Diet (SAD) that is full of processed foods, added sugars, refined grains/flours. Eat 3-4 cups of dark leafy green vegetables, whole animal protein at every meal, and lots of colorful seasonal fruits.
  4. Quell the Inflammation – Use botanicals and nutraceuticals like Curcumin, Rosemary, Ginger, Scutellaria (Baikal Skullcap), and CitriDrops Nasal Spray for the sinuses.
  5. Support the Gut – Support gastrointestinal assimilation, break up any biofilms and re-populate the gut with health microbes. You can use Betaine HCL, digestive enzymes, Immunoglobulin IgG, and healthy probiotic spores.

Having intestinal distress can be not only debilitating but frustrating. Not knowing where it is coming from can even be more worrisome. Consulting with a functional medicine provider for appropriate testing and treatment strategies is vital. Every patient is different and unique. We are bio-individual people that respond differently to nutraceuticals, botanicals, homeopathic remedies, prescriptions, and manual treatments. At Keystone Total Health, we are committed to individualizing our treatment approach so that our patients can navigate these complex health challenges and restore their well-being.


1 – J. Allergy Clin. Immunology. 2012 July 10; Epub ahead of print. PMIDL 22789397

2 –  van Aalderen WM. Childhood asthma: diagnosis and treatment. Scientifica (Cairo). 2012;2012:674204. doi: 10.6064/2012/674204. Epub 2012 Dec 13. PMID: 24278725; PMCID: PMC3820621.

3 – Kraft S, Buchenauer L, Polte T. Mold, Mycotoxins and a Dysregulated Immune System: A Combination of Concern? Int J Mol Sci. 2021 Nov 12;22(22):12269. doi: 10.3390/ijms222212269. PMID: 34830149; PMCID: PMC8619365.

4 – Empting LD. Neurologic and neuropsychiatric syndrome features of mold and mycotoxin exposure. Toxicol Ind Health. 2009 Oct-Nov;25(9-10):577-81. doi: 10.1177/0748233709348393. PMID: 19854819.

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