You wake up feeling exhausted, and you drag yourself through the day. You feel as though you’ve lost your mojo. You have no pep in your step. Maybe you’re anxious, irritable, or forgetful, or you just can’t think straight. All the color has been washed out of your life. Your world has turned gray. You’re well aware that you’re suffering from brain fog, but what caused it?

Well, that’s a tough question to answer. Any number of physical and psychological factors can contribute to brain fog, including poor sleep; nutritional deficiencies; lack of exercise; overconsumption of sugar, refined carbohydrates, alcohol, caffeine, or nicotine; emotional stress; infection; dehydration; and the list goes on.

Brain fog isn’t so much a medical condition as it is a catchall phrase for symptoms related to the onset of a lack of mental clarity, confusion, forgetfulness and a lack of focus.

An often-overlooked cause (or contributing factor) of brain fog is mycotoxins.

What Are Mycotoxins?

Mycotoxins are poisonous substances produced by a fungus such as mold (microscopic fungi) to kill off competing mold species. They enter the body through foods, dust, air, and long-term exposure to water-damaged homes or buildings.Mycotoxin Fungi are a normal part of our environment and food source; they are particularly prevalent in grains. However, in water damaged buildings or homes, mold species that are harmful to your health can be present in overwhelming numbers.

Once in the body they commonly take residence in the nasal passages and lungs and aggregate in the liver or gallbladder where the body attempts to destabilize and eliminate them. For those who are overexposed and are having difficulty breaking down and eliminating the mycotoxins, health problems ensue. Although rarely diagnosed in the clinical setting, mold toxicity represents a large portion of chronically ill patients who are often misdiagnosed with depression or fibromyalgia.

Mycotoxins formed by mold growing in water-damaged homes or buildings can be extremely toxic to humans. One in four people has a genetic hypersensitivity to mold toxins. When these people are exposed to mold, they experience a heightened immune response, resulting in an increase in cytokines — immune system messengers that can cause inflammation. Chronic Inflammatory Response Syndrome (CIRS) may result when the immune system produces a large number of cytokines over a long period of time.

Leaky Brain

The inflammation caused by mycotoxin exposure can lead to a condition sometimes referred to as leaky brain, in which the blood-brain barrier (a protective shield that surrounds the brain) becomes compromised. You may have heard of “leaky gut.” For years, the medical establishment had scoffed at the idea of a leaky gut, viewing it mostly as a holistic fantasy. Today, there are thousands of papers that indicate the importance of leaky gut in human diseases ranging from IBS to autoimmune disease. The same is happening with leaky brain; many in the medical community deny its existence, but they will sooner or later begin to realize that leaky brain is serious health condition.

Leaky brain is similar to leaky gut. With leaky brain, proteins that make up the blood-brain barrier are broken down. Potentially harmful substances that are not supposed to reach the brain pass through tiny gaps in the barrier, leading to chronic inflammatory responses in the brain. Symptoms then follow, including, brain fog, fatigue, muscle pain, anxiety, depression, and memory loss.

Testing for Mold Infection and Related Conditions

The presence of mold can be detected in urine samples and nasal swabs. In addition, blood and urine samples can be checked for markers (traits or characteristics) that indicate the presence CIRS and/or mycotoxins (one of many biotoxins).

Several markers are used to identify CIRS and exposure to biotoxins (including mycotoxins), such as the following:

  • Matrix metallopeptidase 9 (MMP-9): MMP-9 plays an important role in tissue repair and replacement, but excessive amounts of it break down the blood-brain barrier. Elevated MMP-9 is common in biotoxin-related CIRS.
  • Vascular endothelial growth factor (VEGF): VEGF stimulates the formation of blood vessels and increases blood flow. VEGF deficiency is common in biotoxin illness and can create serious health issues due to restricted blood flow to cells.
  • Vasoactive Intestinal Polypeptide (VIP): VIP regulates inflammatory responses. Patients with mold illness have low VIP levels, resulting in shortness of breath especially during exercise.
  • Transformative growth factor (TGF) Beta-1: TGF Beta-1 is a protein that plays an important role in immune system function, especially as related to regulatory T-cells. High levels of TGF Beta-1 have been linked to neurological, autoimmune, and other systemic illnesses.
  • Melanocyte stimulating hormone (MSH): MSH has multiple anti-inflammatory functions. Approximately 95% of patients with mold illness have low MSH levels, which makes them more susceptible to mold illness and leads to fatigue, pain, brain fog, hormone imbalances, irritability, and more.

Tests for mold exposure/illness include the following:

  • Blood, urine, and stool profiles can detect exposure to multiple species of mold, including the most common molds in homes and buildings in North America: Aspergillus, Penicillium, and Stachybotrys, along with all other species documented to have caused mold sickness in the U.S.
  • ICAT allergy testing profile indicates whether you’ve been exposed to toxic mold and, if you have, shows the level of exposure and identifies the species.
  • Myco-M7 series mycotoxin profile tests exposure to mycotoxins, which can remain in the body for several years.
  • Fungal identification (FID) profile provides a strong indication of any fungal infections in the body.
  • Mycobacterium identification (MB) profile tests for the presence of mycobacterium that are synergistic with fungi and produce spores (as fungi do). These spores can produce toxins that cause illness.


Treatment for mold toxin or CIRS requires full-body rehabilitation. Overactivity of the immune system for long periods of time burdens many areas of the body and has to be treated gradually over a span of 6–12 months or longer to increase treatment success.

After identifying the mycotoxin related illness, treatment can be initiated. Treatment begins by identifying and removing or remediating the mold source. This step is best left to mold-remediation experts, because do-it-yourself mold remediation can expose a person to very high levels of mold and toxins.

Next the body needs to be rehabilitated by correcting the chronic inflammation and supporting removal of toxins through the liver, gallbladder, intestines, and kidneys.

Therapeutic nutrients are used to support brain health and rebuild a healthy blood brain barrier.

It is quite common for those suffering with mold to have chronic sinus infections. These infections are often treated, unsuccessfully, with antibiotic therapy. Therefore, I test for hidden sinus infections, and provide any treatment necessary, avoiding the use of antibiotics. I use more natural antimicrobials depending on the infection(s) found. Colloidal silver mixed with adhesive medications can be helpful to reach and stick deep into the sinus cavity, fighting infections that were previously resistant to antibiotics. Reducing the overall cytokine load through fighting hidden infections is an important step to rehabilitation from CIRS.

For the patient, treatment can be summarized as follows:

  1. Run lab tests to diagnose CIRS.
  2. Find the source of mold toxin or other toxins and work towards eliminating it. Other sources of environmental toxins include Lyme, lipopolysaccharides (LPS), and Multiple Antibiotic Resistant Coagulase Negative Staphylococci (MARCONS).
  3. Support a calming of the immune system using a variety of natural treatments ranging from glutathione to natural antibiotics that fight hidden infections.
  4. Help the body to eliminate circulating mycotoxins via the liver, gallbladder, lungs, sinuses, and intestines.
  5. Reduce the chronic inflammatory response using omega 3’s and other natural anti-inflammatories.
  6. Make temporary dietary corrections that support reduction of inflammation and mold exposure.
  7. Assess progress with labs and, if needed, adjust or continue with treatment.

Purging the body of mycotoxins is no small feat, especially because fungi are so pervasive in some environments. However, you can win the battle. If you are suffering from brain fog or have other CIRS-related symptoms, I strongly urge you to get tested. Only after you discover the cause can you begin to take the right steps to identify and remediate the mold and give your body what it needs to eliminate the infection and toxins and begin to feel healthy again.

Disclaimer: The information in this blog post is provided for general informational purposes only, and may not reflect current medical thinking or practices. No information contained in this post should be construed as medical advice from Dr. Matt Lewis, D.C., DACBN, CFMP®, nor is this post intended to be a substitute for medical counsel on any subject matter. No reader of this post should act or refrain from acting on the basis of any information included in, or accessible through, this post without seeking the appropriate medical advice on the particular facts and circumstances at issue from a licensed medical professional in the recipient’s state, country or other appropriate licensing jurisdiction.

About the Author: Dr. Matt Lewis, D.C., DACBN, CFMP®, specializes in diagnosing and treating the underlying causes of the symptoms related to chronic and unexplained illness through nutrition, lifestyle, chiropractic, and other natural approaches to whole-health healing in Tampa, Florida. He earned his B.S. in Biology from Shenandoah University, his Doctorate in Chiropractic from Life University, his Diplomate status in Clinical Nutrition from the American Clinical Board of Nutrition, his CFMP® from Functional Medicine University, and his certification as a Digestive Health Specialist (DHS) through the Food Enzyme Institute. Dr. Lewis’ passion for health and wellness stems from his own personal experience. With a family history of autoimmune conditions and diabetes, and his own lab tests showing his genetic susceptibility to Hashimoto’s thyroiditis (autoimmune thyroid), he has learned how to restore his own health and vigor to prevent the onset of these and other illnesses and live an incredibly active life. Through this process, he acquired a deeper understanding of health and wellness, which he now offers his patients in Tampa.

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