Indoor exposure to molds in a water-damaged building has significant health risks. Molds and the mycotoxins they produce contribute to illness in various ways. Some people refer to illness from exposure to mold as a chronic inflammatory response syndrome (CIRS), but multiple mechanisms of injury are associated with exposure to molds and mycotoxins. This article reviews the published medical research demonstrating how molds and mycotoxins cause illness.
What are Mycotoxins?
Mycotoxins are secondary metabolites produced by molds. Over 400 mycotoxins have been identified, and there are likely many more. Molds produce mycotoxins to allow them to compete in environments for survival. This helps molds colonize in environments, including in humans. Mycotoxins can metabolize into modified mycotoxins, which are more difficult to detect in testing and can be more toxic than the parent mycotoxins.
One mold species can produce multiple mycotoxins, and some mycotoxins are produced by several mold species.
Mold spores are 1-20 microns, and mycotoxins are 0.1-0.3 microns, making them slightly larger than viruses. Inhalation is the most common route of exposure to mold spores and mycotoxins, but they can also be ingested or absorbed through the skin. Regardless of the route of exposure, mycotoxins are systemically bioavailable. When mold colonizes in the body, it can make mycotoxins long after someone leaves a moldy environment.
Oxidative Damage is a Significant Contributor to Mold Illness
Oxidative damage occurs when the production and accumulation of reactive oxygen species (ROS) exceeds the body’s ability to neutralize and detoxify ROS, damaging cells and tissues. Environmental exposures to radiation, pollutants, heavy metals, and toxins are a significant source of oxidative damage. Some common examples of oxidation are the browning of apples and avocados when cut open or when rust forms on iron. Oxidative damage affects cells, tissues, and organs, interfering with proper function.
A significant mechanism of injury includes oxidative stress. A Review of the mechanism of injury and treatment approaches for illness resulting from exposure to water-damaged buildings, molds, and mycotoxins
One study found that treating Ochratoxin A led to increased reactive oxygen species (ROS) and a marker of DNA oxidative stress. The study’s authors found that using the antioxidant N-acetyl-cysteine (NAC) reduced ROS and DNA damage.1
Looking at mycotoxin-induced neurotoxicity from oxidative stress, researchers determined that Ochratoxin A may be responsible for generating free radicals and ROS that result in systemic oxidative damage.2
Another study found that the combined effect of two mycotoxins resulted in a significant increase in markers of oxidative damage.3 When people are exposed to mold in an indoor environment, they are typically exposed to multiple molds and mycotoxins. Aflatoxin has been shown to exert oxidative stress on brain cells and cause degeneration of the cells.4
Oxidative damage to cells, tissues, and organs is the primary cause of symptoms and disease associated with exposure to mold and mycotoxins.
Humans produce the critical antioxidant glutathione, and mycotoxins interfere with the production of glutathione. Therefore, mycotoxins directly cause oxidative damage, and mycotoxins reduce the antioxidant that protects cells from oxidative damage.
Mold and Mycotoxins Cause Immune System Dysregulation
The immune system is sophisticated. It is tasked with protecting us from foreign invaders, yet not attacking our tissue. When the immune system is exposed to an infection or toxin, a cascade of events occurs to neutralize the culprit. The immune system releases cytokines and other mediators that drive inflammation during that process. Molds and mycotoxins cause immune system dysregulation and inflammation.
In 2015, researchers from the Harvard School of Public Health and the University of Illinois published a study examining the immune response of workers exposed to mold in an office building. They found specific immune cytokine and chemokine responses in the workers exposed to mold were significantly higher than those without a history of mold exposure.5
How does mold affect cognitive and emotional health? In 2020, researchers studied the effect of inhaled mold spores on the immune system. They found mold spores increased the cytokine interleukin 1 activity in the brain’s hippocampus region, decreasing the production of new neurons. The exposure to mold spores also caused memory deficits and anxiety-like behavior.6 When I see a patient who is suffering from neuropsychiatric symptoms, I let them know the symptoms are a result of brain inflammation. They are not crazy or losing their mind.
Another study found a dose-dependent relationship between mycotoxin exposure and immune reactivity.7 Low-dose exposure to the mycotoxin trichothecene increased cytokines, chemokines, and inflammation, whereas high-dose exposure caused white blood cell death and immune system suppression.
Mycotoxins Suppress and Increase the Immune System
A 2021 published review article indicates that aflatoxin can cause immune suppression and immune stimulation.8 The authors also reported the mycotoxin gliotoxin worsened an experimental model of autoimmune encephalomyelitis, a condition characterized by the immune system attacking the brain.
Mold illness pioneer and immunotoxicologist Jack Thrasher published a comprehensive review article in 2009.9 He points out that mycotoxins compromise the blood-brain barrier, promoting brain inflammation and the death of nerve cells. The molds aspergillus and penicillium increased a type of white blood cell called neutrophils and increased the releases of the cytokines interleukin-6 and tumor necrosis-alpha (TNF-a). The article mentions the bacteria streptomycetes found in water-damaged buildings produce a toxin similar to the chemotherapy drug doxorubicin.
The immune suppressive and organ transplant rejection drug Cellcept is made from the mycotoxin mycophenolic acid.
Exposure to molds and mycotoxins affects the immune system in more ways than just causing a chronic inflammatory response syndrome.
Mold Exposure Can Cause Mast Cell Activation Syndrome (MCAS)
Mast cells are innate immune cells primarily located in tissues that interface with the outside environment, such as the skin, respiratory tract, and gastrointestinal tract. When triggered by an environmental antigen, mast cells release chemical mediators that can cause generalized symptoms. Aspergillus can activate mast cells to degranulate and release chemical mediators.10
Elevated mold and mycotoxin levels should be considered a cause of mast cell activation syndrome in anyone with a suspected history of mold exposure.
Mold and Mycotoxins Contribute to Mitochondrial Dysfunction
Mitochondria are known as the powerhouse of the cell because they are responsible for making energy for every function in the body. There are about 1000-2000 mitochondria per cell. Organs with higher energy demands, including the brain and immune system, can contain up to 2 million mitochondria per cell.
Damage to the mitochondria affects energy production and is often referred to as mitochondrial dysfunction.
Various insults, ranging from medications to environmental toxins, damage the mitochondria and compromise the mitochondria’s ability to produce energy
Research studies have shown multiple mycotoxins affect mitochondrial function. In a review article published in 2011, authors reported that Ochratoxin A (OTA) caused mitochondrial toxicity and inhibited the primary energy production pathway, the electron transport chain.11 OTA also increased a mitochondrial antioxidant system, reflecting damage was occurring to mitochondria.
The authors of another article report that low levels of mycotoxins cause oxidative stress and may be one of the major causes of mitochondrial dysfunction.12 They go on to say that mycotoxin-induced mitochondrial dysfunction may be related to several chronic diseases.
Physicians in an environmental clinic in southern California conducted a study to determine the prevalence of autoantibodies in patients exposed to molds, mycotoxins, and other toxins.13 Although only a few patients were tested, every patient had antimitochondrial antibodies.
A leading mitochondrial researcher, Robert Naviuax, MD, PhD, has studied mitochondria’s role in chronic diseases. He believes many chronic diseases persist due to incomplete healing from the original insult. He states that healing from chronic illnesses is a whole-body process and begins with the mitochondria and the cell.14 Supporting mitochondrial and cellular health is a primary approach I use to help my patients recover from chronic illnesses.
Neurological Damage from Mold and Mycotoxins
The brain and nervous system are common targets for mycotoxins. Exposure to molds and mycotoxins triggers inflammation in the brain, contributes to nerve damage, and causes symptoms associated with neurotoxicity.
Ochratoxin A (OTA) caused neuronal toxicity and cell death in a dose-dependent manner.15 The authors of the study propose OTA may contribute to the neurodegenerative diseases Azheimer’s dementia and Parkinson’s disease.
In the review article titled Effects of Mycotoxins on Neuropsychiatric Symptoms and Immune Processes, the authors make some important points about how mycotoxins affect the brain.16 People exposed to mold had impaired cognitive functions such as verbal learning, psychomotor speed, and emotional function. People exposed to mold also had decreased attention spans.
Neuropsychological testing done on people exposed to mold had impairments similar to people with traumatic brain injuries (TBIs)
Additionally, children with autism spectrum disorder had significantly higher mycotoxin levels than those without autism.
Mold Compromises the Blood-Brain Barrier
The network of blood vessels that deliver blood to the central nervous system (CNS) is lined with cells that selectively filter out substances that might harm the CNS is called the blood-brain barrier (BBB). Mycotoxins have been shown to damage the blood-brain barrier, allowing other substances to cross into the central nervous system.
One mycotoxin crossed the BBB over 300% faster than the study controls and reached the permeability of morphine, a BBB-permeable drug.17 The authors concluded that since trichothecene (a mycotoxin produced by black mold Stachybotrys) compromised the BBB, it may allow other mycotoxins to enter the brain.
Mycotoxins Role in Multiple Sclerosis
Multiple sclerosis is a debilitating condition that significantly affects the quality of life in those who suffer from it. There is no known cause of MS, but many potential causes have been theorized. Any toxin or infection that causes damage to the myelin sheath that covers nerves has the potential to contribute to MS or “MS-like” symptoms. Mycotoxins are no exception.
The authors of the article Fungal Toxins and Multiple Sclerosis: A Compelling Connection outline a possible mechanism that mold exposure may play in contributing to MS.18 Mycotoxins break down the blood-brain barrier and damage cells that produce myelin (oligodendrocytes). Myelin debris triggers an immune assault that further damages myelin, contributing to the progression of MS.
It is crucial to test for mold illness in anyone with multiple sclerosis. I have successfully treated patients who were diagnosed with MS when we learned they had mold illness
Parkinson’s Disease and Mold Illness
Parkinson’s Disease is another neurodegenerative condition that is characterized by oxidative damage. The authors of a research study looked at DNA oxidative damage in the brain following the administration of low-dose ochratoxin A (OTA).20 A decline in dopamine levels – the hallmark feature of Parkinson’s disease – occurred in the dose-related exposure to OTA.
The authors concluded that low-dose exposure to OTA will result in early Parkinsonism when the normal age-dependent decline in dopamine levels is associated with mycotoxin exposure.
How Does Mold Affect Digestive Health?
Many people with chronic illnesses suffer from functional digestive symptoms. People will chase digestive symptoms with various supplements and diets and continue to experience symptoms. I was surprised to see several research studies exploring mold and mycotoxins’ role in gut health.
Foods, especially grains, can easily be contaminated with mold growth. In the United States and other developed countries, the food supply is tightly monitored to ensure foods are not spoiled by mold growth; however, low mold levels may find their way into our daily diets. Mold and mycotoxins can affect healthy gut bacteria, which is essential for immune system function, digestion, and production of vitamins. Beneficial gut bacteria are also responsible for metabolizing mycotoxins into less toxic metabolites, so microbiota health may determine if someone gets sick from ingesting mold-containing foods.21
Mycotoxin can affect the intestinal barrier, contributing to leaky gut syndrome, and allow bacteria and other pathogens in the gut to cross the intestinal barrier and cause an inflammatory response. An excellent article reviews mycotoxins’ role in damaging the physical, chemical, immunological, and microbial intestinal barriers.22 The article also suggests mycotoxins might play a role in the development of chronic inflammatory bowel disease.
Is it SIBO or SIFO?
Many people are familiar with small intestine bacterial overgrowth (SIBO) and the symptoms it causes. SIBO is responsible for about two-thirds of irritable bowel syndrome (IBS), a condition historically thought not to have a known cause. Mold can colonize the intestinal tract and cause small intestine fungal overgrowth (SIFO). There is no direct test for SIFO, but I suspect it in my patients with a history of mold exposure, gas/bloating, abdominal discomfort, and inconsistent stool consistency.
When mold is colonized in the body, it can produce mycotoxins long after the person has left a moldy environment. Colonized mold is not treated with anti-yeast/candida medications like fluconazole or nystatin.
Mold and Mycotoxins Cause More Than a Chronic Inflammatory Response Syndrome
As scientific research indicates, mold illness can result from multiple mechanisms of injury. Mycotoxins primarily cause damage to cells, tissues, and organs through oxidative stress, immune system dysregulation, neurological damage, and mitochondrial dysfunction. These impacts result in symptoms including fatigue, difficulty concentrating, joint pain, headaches, anxiety/depression, mood swings, and digestive symptoms. Recovering from mold illness requires more than using binders. It requires complete healing of cells, tissues, and organs affected by mycotoxins.