Mast Cell Activation Syndrome

Holistically Healing Mast Cell Activation Syndrome and Histamine Intolerance

Today, we’re taking a deep dive into Mast Cell Activation Syndrome (MCAS). I invited our lead clinician, Nicole, to guest blog on this topic. Nicole is a state-certified, double board-certified holistic and clinical nutritionist who has lived with MCAS for almost a decade and now guides others in how to regain their well-being.


When I was first diagnosed with MCAS, I didn’t know what it was. All I knew was that I had gone from a happy, high-functioning person to someone who was pretty much allergic to life – a literal “bubble person.”

It had started a few months before, after experiencing a vaccine injury that cascaded into a complete body breakdown over the following months. I experienced anaphylactic reactions to everything I ingested (food, supplements, liquids, medications) and I couldn’t sit, stand, or walk without my heart rate skyrocketing and sometimes fainting. I lost 90 pounds, spent over a month in the hospital, was unable to walk, and could only eat 4 foods without having anaphylactic reactions. I was rendered totally disabled for the better part of a year and had to use a wheelchair when I left the house.

Eventually, I was diagnosed with MCAS and Postural Orthostatic Tachycardia Syndrome (POTS) and was handed some medications and told to learn to live with it. What was surprising to me was that none of the physicians I encountered along the way ever discussed nutrition or supplements with me.

Being a root-cause practitioner and believing deeply in the power of food as medicine, I knew I had to go beyond managing symptoms and look for the underlying pieces to the puzzle so that I could give my body the tools it needed to begin healing.

When you have a mast cell condition, the million-dollar question always is “how do I start healing when I react to EVERYTHING?” The answer is that you have to figure out the pieces to YOUR puzzle – every person is different and it can be complex. But the key is to approach your healing holistically – addressing body, mind, AND spirit. More on that below.


Mast cells are white blood cells that are part of your immune system and are found throughout your body. They release up to 200 pro-inflammatory mediators (histamines, cytokines, prostaglandins, leukotrienes, etc.) that help your body fight pathogens and allergens.

When you have a mast cell disorder, you may have an abnormally high number of mast cells (Mastocytosis) or you may have a normal number of mast cells that become hypersensitive and hyperactive (MCAS). With MCAS, your mast cells constantly release mediators when they shouldn’t and essentially don’t “turn off,” causing you to be in a chronic allergic state. Mast cells can be triggered by anything and everything – food and beverages, chemicals, stress, temperature changes, exercise, air pollutants, medications, altitude, supplements, and hormone fluctuations (women often experience a flare in symptoms around their menstrual cycle).

Symptoms vary depending on the person and can affect any system in the body. They can include things like anaphylaxis, flushing, hives, gastrointestinal issues (abdominal pain, diarrhea, and bloating), low blood pressure, brain fog, headaches, and heart arrhythmias.

MCAS is typically diagnosed by a mast cell specialist or allergist/immunologist using different tests, including:

  1. Bone marrow biopsies
  2. Serum tryptase levels
  3. Urine levels of histamine, prostaglandins, and leukotrienes

Testing can be tricky, as your lab results can come back normal if you are not in a mast cell flare at the time the test is performed. Because of this, some people are diagnosed with MCAS based on symptomatology, especially if their symptoms improve when taking antihistamines.


No. Histamine intolerance (HI) and MCAS are two different conditions that share similar symptoms and sometimes overlap. Often, but not always, a person with MCAS also has HI. Unlike MCAS, which causes your mast cells to become overactive and release mediators (beyond just histamine), HI is when you have trouble breaking down histamine (particularly when you eat) and it accumulates in your body and causes symptoms.

Histamine is mainly broken down by two enzymes: Diamine Oxidase (DAO) in the small intestine and Histamine N-methyltransferase (HNMT) in the central nervous system. HI typically occurs when your body does not produce enough DAO, which limits your ability to break down dietary histamine, especially if you eat too many high-histamine foods.  


The traditional medical protocol for MCAS generally uses a combination of high-dose antihistamines, mast cell stabilizers, and leukotriene inhibitors. The most common medications used are:

  • Histamine 1 (H1) blockers: Claritin, Benadryl, Zyrtec, Allegra, Atarax
  • Histamine 2 (H2) blockers: Pepcid, Tagamet, Zantac
  • Mast cell stabilizers: Cromolyn Sodium, Gastrocrom, Nasalcrom. Ketotifen (also an H1 blocker)
  • Leukotriene inhibitors: Singulair, Zyflo, and Accolate
  • Other medications: Xolair (neutralizes antibodies), low-dose naltrexone (reduces T-cell dysfunction), and aspirin (a prostaglandin inhibitor that may cause reactions in some people, especially those with salicylate sensitivities)


There are many wonderful natural strategies that can be highly supportive in addressing MCAS. But every person experiences MCAS differently, and there is no single diet, supplement, or medication that will work for everyone. So, it will take some time and experimenting with both conventional and natural remedies (under the guidance of a health care practitioner) to see what works for you. But taking a holistic approach that addresses your body, mind, AND spirit is the “secret sauce” to healing.


Identify Your Triggers: Mast cell flares can be triggered by different things, such as foods, chemicals and fragrances, toxins, temperature changes, and medical procedures, among others. Learning what your triggers are can help reduce your exposure to these things while you are healing.

Adjust Your Diet: Diet is a KEY part of recovery and eating a low-histamine diet is a great place to start. But your triggers may not include histamine or may include other things like oxalates or salicylates. In general, avoid left overs, slow-cooked bone broth, packaged and processed foods, fermented foods, gluten, and dairy. Some examples of foods with great antihistamine and mast cell stabilizing properties are apples, arugula, broccoli, dandelion root, ginger, mangoes, red onions, turmeric, and watercress.

Don’t know where to start? Keeping a food journal is a great way to keep track of what you eat and identify any patterns between specific foods and symptoms. I have also found MRT food testing to be very helpful in identifying food triggers. Our first inclination is usually to reduce our diet down to a few “safe foods” (which is totally understandable). But when you do this, you can experience nutrient deficiencies that lead to other health issues and prevent your body from healing. So, I always work with clients on expanding their diets, using specific strategies to reintroduce foods in a way that minimizes reactions and provides the body with as many nutrient-dense foods as possible.

Balance Your Sex Hormones: There is a direct connection between mast cells and your sex hormones. Estrogen stimulates our mast cells to release histamine and our bodies to make more estrogen while also reducing DAO activity. This creates a histamine-estrogen cycle that can cause some people to enter a state of “estrogen dominance.” (This is why many women experience a flare in symptoms around their menstrual cycle.) In contrast, testosterone and progesterone are mast cell stabilizers (progesterone also helps increase DAO levels in the body). The first step is to test your hormone levels and then work 1-1 with a health care practitioner who can oversee any adjustments you may need.

Address Gut Issues/Underlying Pathogens: Those with MCAS may have some degree of gut dysbiosis (“leaky gut”) or chronic infection caused by underlying pathogens such as candida/fungus, small intestinal bacterial overgrowth (SIBO), parasites, or pathogenic bacteria. These pathogens cause an inflammatory response that triggers your mast cells to degranulate. (It’s no surprise, as mast cells are found in high concentrations in your gastrointestinal tract.) The most common underlying infections that I have seen in my practice are Lyme disease, SIBO, candida, mold illness, and mycoplasma. Comprehensive stool testing, like the GI Map or CDSA tests, can help you identify these gut issues. The Mycto-Tox and organic acids tests can also help identify mold, gut dysbiosis, and nutrient deficiencies.

NOTE: If you find that you have an underlying infection, do not address it until you have first stabilized your mast cells with medications, supplements, and/or both and your detoxification channels are open and functioning properly.

Clean Up Your Environment: The environment where you live and work can contain chemicals, fragrances, and other toxins that may trigger your mast cells to degranulate. So switch out your personal care products (shampoo, deodorant, skin care, makeup, etc.) for natural versions. You may need to put some of these products aside until you gain some healing. Make your living and workspaces fragrance-free if that’s at all possible and limit your exposure to EMFs. Using air filters in your home and car and water filters on your sink and shower can go a long way in helping to reduce your symptoms.

Use Targeted Supplements: Supplements can be tricky, as most people with MCAS do not tolerate very many, if at all – especially, in the beginning of their healing journey. But if you can tolerate them, supplements can be a great tool to gain some traction in your healing. Here are some things to keep in mind.

  1. Always, always, always microdose. Never start with the normal dosage. Instead, start with ¼ of a capsule or tablet (or even less) and see how your body reacts. If you tolerate it, stay at that dose for a period of time (at least 1-2 weeks) and gradually increase it until you reach the dose that you tolerate. You may only tolerate a small amount and may only be able to take it once or twice a week, and that’s perfectly ok.
  2. Always introduce one supplement at a time. This will help you to pinpoint which supplements you react to.
  3. Use different delivery methods. If you don’t tolerate supplements orally, you may be able to take some of them in a way that bypasses the GI tract – intramuscularly, intravenously, transdermally, or sublingually.
  4. Choose clean formulas. When starting out, it’s best to choose single-ingredient supplements rather than combination formulas, so that you can identify any reactions. Also, choose high-quality brands that contain the fewest secondary ingredients and fillers.
  5. Don’t get discouraged. If you react to a supplement, try not to get down about it, as there are many different remedies that you can try. You just need to find the one that works for YOU.

Here are just a few of my favorite supplements (never make changes to your MCAS medications or supplements without running it by a trusted health practitioner):

  • Bioflavonoids: These phytochemicals stop the release of histamine, leukotrienes, and prostaglandins. One of my all-time favorite products, Neuroprotek, contains quercetin, rutin, and luteolin. (It was developed by Dr. Theoharides, a mast cell researcher, as an alternative to pharmaceutical mast cell stabilizers). If you don’t tolerate it, try taking them separately, starting with quercetin. If you don’t tolerate quercetin or luteolin, try Pycnogenol. (You may not tolerate quercetin if you have a salicylate sensitivity or certain COMT genetic mutations).
  • Vitamin C: A potent natural anti-histamine, mast cell stabilizer, and DAO booster, Vitamin C is best obtained from whole food sources, such as Camu Camu powder. Avoid Ascorbyl palmitate supplements, which are fermented, unless you can find one made from tapioca. Also avoid Ascorbic acid supplements, unless it is not derived from fermented corn.
  • Perilla Seed Extract: This herb contains luteolin and rosmarinic acid that help stabilize mast cells by lowering histamine and cytokine levels. It can be particularly helpful with respiratory inflammation.
  • Decaffeinated Green Tea Extract: This supplement removes caffeine from green tea leaving Epigallocatechin Gallate (ECGC), which stabilizes mast cells, inhibits them from producing leukotrienes, and inactivates the enzyme that makes histamine. It has a similar effect as ketotifen. (People with certain COMT genetic mutations may not tolerate this.)
  • Vitamin D: A powerful hormone and mast cell stabilizer, Vitamin D can help reduce MCAS symptoms. When I was first sick, I noticed that I always felt better in the summer, when I would lay out in the sun almost daily. Always test your Vitamin D levels before supplementing. Light sources like sunshine and/or Vitamin D lamps are best. If you supplement, choose a formula that also includes Vitamin K2 for better absorption.
  • Magnesium: People with MCAS often have low levels of magnesium, which your body needs to regulate histamine levels (it’s needed to make DAO) and manage its stress response. If you don’t tolerate oral supplements, try using a small amount of Magnesium oil on your skin or Magnesium Flakes in a bath or foot soak. For more information on different types of magnesium, click here.
  • Chinese Skullcap: A natural mast cell stabilizer, Chinese Skullcap helps lower histamine levels and has an anti-inflammatory effect, particularly in the respiratory tract.
  • Stinging Nettle Leaf: This herb is a superstar natural antihistamine, mast cell stabilizer, and blood sugar balancer that is a rich source of Vitamin C. It balances your body’s immune response, especially in the respiratory tract, by inhibiting your mast cells from releasing prostaglandins and leukotrienes.
  • DAO: If you have histamine intolerance and have trouble digesting histamines in your foods, supplementing with DAO can help. DAO supplements are generally made from porcine, so if you have a pork sensitivity, you may not tolerate them. A vegetarian alternative is to juice pea shoots, which have high levels of DAO.
  • Probiotics: Those with MCAS have to be careful when choosing a probiotic because some strains actually increase histamine levels in the body. Look for probiotics with histamine-friendly strains, which generally include bifido strains and certain lactobacillus strains (Plantarum, rhamnosus, and gasseri).


Try Neuroplasticity Training: Brain retraining programs, like the Gupta Program or DNRS, can be a game-changer for those with MCAS. The body’s stress response begins in the limbic system of the brain. Chronic stress and trauma can cause the limbic system to malfunction and stay in a chronic stress response. These programs teach you different daily exercises that you can do to retrain those parts of your brain so that it doesn’t stay in a state of hypersensitivity. Retraining your brain in this way is often one of the MAJOR pieces of the puzzle for those with MCAS.

Stimulate Your Vagus Nerve: The vagus nerve is the longest nerve in your body that connects your brain, heart, and gut. It activates the parasympathetic system and can help stabilize your mast cells. Stimulating your vagus nerve can have an anti-inflammatory effect and has been shown to stop cytokine production in different parts of the body. To stimulate your vagus nerve, you can do simple exercises like singing loudly in the shower, gargling, and gagging (using a tongue depressor on the back of your throat).

Manage Your Stress Levels: Easier said than done, right? But anyone with MCAS knows that stress is a MAJOR trigger, and that stress management is a key component of recovery. Why? Because when you are under chronic stress (whether it’s physical or emotional), a part of your brain called the hypothalamus releases corticotropin-releasing hormone (CRH), a hormone that signals your adrenal glands to release cortisol. CRH activates mast cells and chronic stress keeps reactivating them. Over time, your cortisol levels can become depleted, further increasing inflammation. Meditation and breathwork can help switch you out of that sympathetic stress response and into a parasympathetic response (rest-digest-and-heal).

Use biofeedback techniques to regulate stress and emotions: HeartMath uses a biofeedback app and a sensor that you clip to your ear to track your heart rate variability in real-time. It teaches you techniques to change your heart rate pattern so that you can control your physiological and emotional response to stress and shift into a state of alignment between your brain, heart, and emotions (called “coherence”).


Accept Where You Are: When you are healing from MCAS, it’s important to meet your body where it’s at in the present. This is a tough one for people – we tend to focus on what we used to feel, what we used to look like, what we used to eat, and what we used to do. But in order to start healing, you have to fully accept where your body is right now. When dealing with MCAS, we often have one foot in the past (pre-illness) and one foot in the future (restoration of health). But the truth is that all we really have is the present, and until we surrender to that we are resisting healing.

Identify Limiting Beliefs: We all have certain beliefs that we carry, either consciously or subconsciously, that limit us. They can be passed down to us by our families, society, or through significant life events, experiences, or traumas. Examples of limiting beliefs are “I’m the sick one,” “I don’t deserve to be healthy,” or “I will never get better.”

So often we store limiting beliefs, painful experiences, and traumas in our bodies and we don’t even realize it. Examining, processing, and releasing these beliefs and traumas is an important part of healing.

Adopt a Gratitude Practice: Having MCAS is a hero’s journey. There are times that it is straight up maddening, overwhelming, and frustrating. The important thing is to feel all of those feelings and not suppress them – it’s totally normal and valid. But try not to stay in that space longer than you need to. Remember to show yourself compassion. Illness is something you are experiencing and not who you are. Try and shift your thoughts and find things you are grateful for – even if they are small – and build from there. Gratitude is one of my favorite practices. It may seem forced at first, but If you stick with it, over time it really shifts your perspective.

Find a Support System: Having MCAS involves a level of sensitivity that most people, including practitioners, don’t fully understand because they haven’t experienced it. It can impact your relationships, your finances, and your career. Surround yourself with people who love and support you. Find a healing team of practitioners who listen to your experiences, answer your questions, and view your relationship as a partnership. Finding the right support can make all the difference in guiding you through your healing journey.


I hope you enjoyed Nicole’s guest blog and learned a lot about MCAS and how to recover from it. For more about Nicole, or to work with her privately, you can visit her website  


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