Phenol Intolerance: A Symptom of Mold-Induced Illness


  1. My Experience with Food Sensitivities

  2. Phenol Intolerance: A Case of System Overload, Rather than a True Allergy

  3. What are Phenols?

  4. Symptoms of Phenol Intolerance

  5. Phenols in Foods


A huge part of my health puzzle has been figuring out the food intolerances that I gradually developed as a result of Lyme disease, and finding ways to either manage them or overcome them. When the immune system is under stress due to a long-term infection, the hypersensitivity state the body has entered can cause the immune system to start reacting to a variety of foods that previously may not have bothered a person at all. People with Lyme disease often have to be very strict with their diets, as I have, in order to feel well. I personally found that avoiding the foods that I was sensitive to, at least for a time, helped my body heal fairly quickly.

My Experience with Food Sensitivities

Figuring out my food intolerances was an extremely frustrating process that I undertook entirely on my own the past couple of years. Often when I tried to discuss my suspicions about my food intolerances with doctors or nutritionists, they had no idea what I was talking about; the subject of histamine intolerance (and how probiotics can help) and other food sensitivities was almost entirely foreign to them, even to many of the more “holistic” doctors that I saw. However, my background education in biochemistry and nutrition actually helped me enormously in sorting out the intolerances, because once I knew which types of foods were bothering me and exactly what types of molecules in those foods were the culprits, my understanding of nutritional science helped me identify why certain related foods were causing similar problems.

I really wish there were food allergy tests available that could uncover the types of sensitivities that I am discussing, but unfortunately, there really aren’t any available at this time that have the capability of doing that, at least not to my knowledge. Therefore, the process of sorting it all out often requires that one do an elimination diet, and take notes about how certain foods make them feel upon reintroduction. However, I hope that sharing my own experiences will help you uncover some of your own food sensitivities, without having to go through one elimination diet after another. There are few things worse than feeling sick every time you eat, because you have no idea what food is causing your problems. I truly hope to help other people avoid such an awful situation.

Phenol Intolerance: A Case of System Overload, Rather than a True Allergy

The most frustrating food sensitivity I have dealt with, and have largely overcome now, is the topic of my post today. It is called phenol intolerance. I think that phenol intolerance could potentially be a HUGE undiagnosed issue for many people dealing with illness due to toxic mold exposure, and also for people dealing with fungal problems such as candida overgrowth. Read on to find out why!

What are phenols?

Phenols are molecules that occur naturally in plants and act as a preservative or insecticide that protects the plant and lengthens its lifespan. 1 They are found in countless foods that people eat on a daily basis, including fruits, vegetables, nuts and seeds. Salicylic acid is one example of a phenol, and is similar in structure to the active ingredient found in the drug aspirin. The structure of salicylic acid is shown below. You can see that it has a ring-shaped structure, which is called a benzene ring, and there are hydroxyl structures (the OH’s) attached to the ring. This ring structure with OH’s attached is the basic structure of a phenol.



So why do I think that phenol intolerance is a big deal for people struggling with mold-induced illness or fungal overgrowth? I believe phenol intolerance is a major problem because molds and other fungi produce toxins (called mycotoxins) that have the same basic chemical structure as phenols found naturally occurring in foods. So, while someone who does not have a fungal/mold illness may be absolutely fine eating numerous high-phenol foods (which are not a problem in and of themselves), a person with mold illness may have a very low tolerance for those foods because her body is already under stress trying to metabolize the phenol mycotoxins that are being produced internally by the fungi. Metabolizing mycotoxins requires the activity of specific enzymes and the use of substances called cofactors. When these are being “sed up to metabolize mold toxins, there will not be enough enzymatic activity available to metabolize phenols from foods. This will leave the body with very little leeway to tolerate extra ingested phenols from foods, and anapparent “intolerance” of phenols will result.

Pictured below are aflatoxin (lower left) and ochratoxins (lower right), two types of mycotoxins. Aflatoxin and ochratoxin are produced by various species of Aspergillus mold.2 You can see that their chemical structures have a similar structure to salicylic acid, pictured in the image above. Molecules that are shaped similarly can sometimes have similar effects within the body, and mycotoxins and phenols definitely exert similar effects.


Symptoms of Phenol Intolerance

Phenols found in foods have various effects on humans. Interestingly, some of the symptoms of eating too many high-phenol foods are similar to the symptoms of ingestion of mycotoxins, due to their similar chemical structures. There are numerous symptoms of phenol intolerance. Symptoms will often occur shortly after ingestion of the offending high-phenol food.

Phenol Intolerance symptoms:

  • Rhinitis

  • Urticaria (hives)

  • Eczema

  • Gut inflammation3

  • Mood Swings

  • Blood Sugar dysregulation

  • Headaches or migraines

  • Irritable Bowel Syndrome

  • Tinnitus

  • Irritability

  • Restlessness

  • Irregular Heartbeat

  • Asthma

  • Joint Pain

  • Arthritis

Of these symptoms, I think sinus congestion and inflammation, rashes and other skin problems, tinnitus, headaches, shortness of breath, and mood issues are the most common.

Phenols in foods

Here is a chart of foods organized by their phenol content (Well, technically they are organized by salicylate content, because salicylate is the most well-studied phenol in terms of human health effects). The ranking still holds overall in terms of phenol content:



Note: Berries and tomatoes are among the highest phenol foods (hence the blueberries, raspberries, and cherry tomatoes pictured in the feature image). I used to have a terrible problem eating these foods. I can now eat berries of any type with no problems, since I have treated my illness. I don’t eat tomatoes very often, simply because I don’t really like how they taste. But that’s just me!

Once I learned about phenol intolerance, I began to be aware of how many high-phenol foods I was eating; sure enough, I was consuming lots of high-phenol foods, from various fruits and vegetables. After following a low-phenol diet for a few months, I felt significantly better. However, I was doing the low phenol diet in conjunction with serious treatment for mold-induced illness, so I was addressing the root cause of the phenol sensitivity, the mold. Food was not the reason why I was sick – the mycotoxins from mold-induced illness were making me sick, and high-phenol foods were simply putting extra strain on my body. Now that I have addressed my mold-induced problems, I can eat plenty of high-phenol foods and feel absolutely fine!

Finally, there are some ways that you can enhance your body’s metabolism of salicylates, so that you might be able to eat more of them with lessened reactions. Calcium-d-glucarate is a supplement that enhances a process called glucuronidation within the liver. Glucuronidation is the process by which phenols are “neutralized” and prepared for excretion from the body. Coincidentally, calcium-d-glucarate can also be a helpful substance for people dealing with mold illness, as it helps to neutralize mold mycotoxins! This is a prime example of the similarity between phenols in foods and mold mycotoxins.I like to take Thorne Research’s Calcium-d-glucarate.

Molybdenum is a trace mineral that can be taken to assist with the metabolism of phenols by the body. I like to take Kirkman Labs molybdenum. However, before you begin supplementing with this mineral, it might be helpful to get some bloodwork done to measure your current micronutrient status, to make sure you won’t be raising your molybdenum levels too high in the attempt to quench phenol sensitivity.



  1. Race, S. (2002). The salicylate handbook: Your guide to understanding salicylate sensitivity. UK: Tigmore Books.

  2. Zain, M.E. (2010). Impact of mycotoxins on humans and animals. Journal of Saudi Chemical Society. 15(2): 129-144. Retrieved from

  3. Baenkler, H.-W. (2008). Salicylate Intolerance: Pathophysiology, Clinical Spectrum, Diagnosis and Treatment. Deutsches Ärzteblatt International, 105(8), 137–142. Retrieved from

4 thoughts on “Phenol Intolerance: A Symptom of Mold-Induced Illness”

  1. This is my problem exactly. I get migraines from phenols and treated (iodized) salt and I too suffered from mold illness as well.
    I’m mostly back to normal now but the intolerance never went away. I found that glycine neutralizes the effects of the salt and phenols. I can eat these foods as long as I consume glycine immediately after a meal.

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