Cognitive Deficits or “Brain Fog” Associated With Mold, Yeast, and Infections

by Dr. Susan Tanner, MD

Brain fog” is not a medical or scientific term per se, but rather is used to describe how one feels when thinking is sluggish and fuzzy. In other words, when you have brain fog, it may be more of a feeling than a diagnosis, like when you feel confused, disorganized, or find it hard to focus or put thoughts into words. One of my favorite ways to describe it is when you purposefully walk into a room to get something, and upon arriving, totally forget why in the world you walked into that room in the first place. We can all relate, right? While is likely that most of us have experienced this form of brain fog from time to time, following or during an illness, when sleep-deprived, or when brought on by certain medications, when this cognitive fuzziness becomes chronic, persisting for days, weeks, and longer, that is certainly an issue of greater concern–as it should be! In this article, I want to examine the underlying causes of brain fog and some treatments that can be extremely important.

Brain Fog and Mold

For patients with mold and mycotoxin illness, brain fog is one symptom that presents with astonishing regularity to greater or lesser extents depending on the situation, age, and health of the patient. The patient’s particular genetics and the duration of the mold exposure are also at play.  Why does this happen?  There are several mechanisms at work here.  The toxins produced by the molds can easily cross the blood/brain barrier.  When patients have many sinus symptoms and develop a fungal ball in one or more of the sinus cavities, that reproducing mass is separated from the brain only by a very thin layer of bone.  Even without this, the volume of mycotoxins produced and disseminated throughout the body by the colonization of the fungi in the sinuses is enough such that the liver cannot bind and remove them, particularly when there is ongoing exposure as well.  As the mycotoxin levels continue to build in the body, normal oxygenation and biochemical processing of the brain cells are impacted and the result can cause not only brain fog but a host of other neurological effects such as visual and perceptive abnormalities.

Candida and Brain Fog

Individuals with an overabundance of candida in the digestive tract may have quite pronounced brain fog without necessarily having any other gastrointestinal symptoms.  Long ago when I first enrolled in course studies with the American Academy of Environmental Medicine, we were taught that “brain fog is yeast until proven otherwise”. I still find this to be true although the yeast may be coexisting with other factors such as mycotoxins.   Candida can actually create a situation in the small intestine in which it can be considered an “auto-brewery”. When candida has taken up residence, sometimes gut fermentation creates a condition in which ethanol is produced through endogenous fermentation by fungi or bacteria in the gastrointestinal (GI) system. Patients who have this syndrome present with many of the signs and symptoms of alcohol intoxication, even though many do not drink alcohol. The key is that they often do report a high-sugar, high-carbohydrate diet that fosters yeast growth and fermentation. No wonder they feel impaired!

Long COVID and Brain Fog

In recent times, we are hearing more and more about the effects of “long COVID” and the brain fog associated with it even after the acute symptoms of the virus are gone.  While the exact mechanism is not completely understood, it is thought to be the ongoing activity of inflammatory cytokines, part of the immune system that gets switched on by the virus. One of the downsides of this chronic inflammation is that it can reach certain cells and centers of the brain. Brain fog, weakness, numbness, and tingling, continued loss of taste and smell are all symptoms of this inflammation. Interestingly, once turned on, this inflammation can be difficult to dampen. This is presentation can also be found in those individuals with mold and mycotoxin exposure.

Chronic Infections

Also of note, chronic infections of some types, particularly Lyme disease, may present with brain fog as well.  Since these stealth infections can be turned “on” during times of stress or mold exposure, it is harder to diagnose or pinpoint the exact cause of the cognitive symptoms, but thinking about their presence and possible role certainly needs to be part of the differential in considering the cause.

Brain Fog. Now What?

What do you do if you feel that you have ongoing brain fog? This brings us around to the adage that we repeat in almost every article here.  You MUST have clean air, clean water, and clean food.  Even if you suspect that you have long COVID, the coexisting circumstances must be as clean as possible so as not to add to the problem and exacerbate symptoms. But, most importantly, seek out the care of a physician who can help diagnose and dig deep into your personal biochemistry and history.   Certainly, other physical illnesses must be ruled out, such as autoimmune diseases like Multiple Sclerosis, tumors, and systemic issues that can impact the brain.  If this is done and brain fog persists, more needs to be assessed medically. Unfortunately, in this day and age of medicine, there is a tendency to label things that don’t have an obvious diagnosis on blood and limited physical exams as mental illness and then medicines are prescribed which may add another layer of problems.  Please note, I am NOT anti-medication, but rather an advocate for a thorough investigation into the cause of the symptoms BEFORE prescribing medications.

With all of that said, what do you do if you have brain fog and you are pursuing the cause?  There are some lifestyle and behavioral things that can help. As a matter of fact, in my research for the writing of this article, I came across a blog by Andrew E. Budson, MD, a contributor to the Harvard Health Blog which I found quite helpful. While Dr. Budson was speaking mostly toward those with long COVID symptoms, I believe the same interventions can help with other causes of brain fog too:

1. Perform aerobic exercise. You may have to build up to this but do what you can to gradually work toward 30 minutes a day, 5 days a week.   Personally, I prefer this exercise to be outside whenever possible as the added benefit of sunlight and fresh air (assuming these are present) can give additional support to the body.

2. Eat a Mediterranean-type diet with plenty of healthy fats, vegetables, nuts, and seeds. This type of diet can help improve thinking, memory, and brain health in general. It focuses on whole, non-processed foods, which helps to also eliminate sugars and additives that feed candida.

3. Avoid alcohol and unnecessary drugs. Avoiding things that “cloud” your brain also gives your brain a chance to heal.

4. Sleep well. During sleep, your brain and body can clear out toxins and heal.

5. Participate in social activities. Social activities not only benefit our moods but help our thinking and memory as well. Isolation can also lead to depression and bad habits that foster brain fog. For many, socializing needs to have balance, but it is important to your brain health to make time for others.

6. Pursue brain-beneficial and stimulating activities, including activities like problem-solving, crossword puzzles, Sudoku, etc. Listen to music. Practice quieting the mind with prayer or mediation.  Additionally, keeping a gratitude journal helps develop a positive mental attitude. In other words, use your brain so that you don’t lose your brain.

Helpful Nutritional Supplements

There are additional nutritional supplements that may also help with brain fog.  (Note: If one is still in a moldy or toxic environment or eating a bad diet, then these will not help. Addressing those things should come before supplements, in my opinion.)

1. Quercetin – For long COVID or for anyone with persistent inflammation from mold-related illness or post-viral illness then Quercetin or Quercetin-containing supplements, like Histamine Relief, 500 mg twice daily, and CDP choline, 1000 mg twice daily, may help reduce persistent inflammation and heal neural membranes.

2. Glutathione helps the liver continue to process toxic by-products as well as taking down the toxic burden on the brain, regardless of cause.

3. L Theanine, Melatonin, and other sleep support supplements help to regain proper sleep patterns and reduce excessive stress effects on the central nervous system.

There are others as well, but it gets more specific as to cause to specify those. And as this article is not intended to treat every possible situation, I will not delve into that here.

Finally, determining what is brain fog vs. what is true cognitive decline, and if there is a difference will be a topic for future discussion.  There are commonalities between the two, but the big takeaway for this article is to take care of your brain in whatever way that you possibly can while brain fog is still reversible!

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