Histamine intolerance is a fairly new concept in the natural or functional medicine world, and mainstream practice is reluctant to acknowledge it even exists. Mast Cell Activation Syndrome (MCAS) has been acknowledged for a while, but most doctors assume it’s a rare condition. That’s not necessarily the case. In fact, Dr. Lawrence Afrin, a leading mast cell researcher, has been quoted saying he believes that of those living in North America, 15 to 20% may be affected by MCAS. These two conditions can create a lot of distress in navigating food and the environment. Here’s an overview of MCAS and histamine intolerance.
What Are Mast Cell Activation Syndrome and Histamine Intolerance?
MCAS is considered a Mast Cell Activation Disorder (MCAD), along with a rare genetic condition called mastocytosis. MCAS is a condition in which specialized immune cells, white blood cells called mast cells, are frequently triggered to release chemical mediators.
The process of releasing mast cell mediators is called degranulation, and the mediators released include inflammatory cytokines, bradykinin, prostaglandins, leukotrienes, and histamine. When mast cells release these mediators, it can lead to inflammation and allergic symptoms throughout the body.
Now, it’s completely normal for mast cells to produce histamine and other inflammatory mediators. The problem comes when that happens too often, for too long, and the body cannot break down the histamine quickly enough. The result is that histamine builds up in the body, causing all kinds of aggravating symptoms. That is referred to as histamine intolerance or histaminosis.
What makes mast cells so easily triggered or reactive? As we’ll go over later in the article, it goes back to the 3 T’s: traumas, toxins, and thoughts. There’s usually some major initial trigger, like an infection, mold exposure, trauma, or major chemical exposure.
Symptoms of MCAS vs. Histamine Intolerance
MCAS and histamine intolerance have many overlapping symptoms, as they are both affected by histamine. The main difference between the two is that histamine intolerance tends to be more food-related, as mast cells release more histamine than normal when exposed to certain foods. 
MCAS causes mast cells to release histamine and other inflammatory mediators when there’s exposure to other environmental triggers beyond food. Any form of stimulus, trigger, or stressor can set off the mast cells, including anything that impacts the five senses: so, sounds, light, smells, foods, or skin exposures.
Histamine Intolerance Symptoms
Strictly histamine intolerance symptoms are usually related to eating histamine-containing foods or histamine-releasing foods.
- Allergic rhinitis (congestion, runny nose, itchy nose, sneezing, post-nasal drip)
- Red eyes or itchy eyes
- Low blood pressure
- Other reactions to high histamine foods (aged, fermented, leftovers)
These symptoms may also be present in MCAS, but MCAS tends to affect more body systems.
MCAS is a bit more involved. Essentially, you can get symptoms anyplace in the body where there are mast cells or histamine receptors.
- Skin symptoms: rash, spots, redness, hives/itching, mouth sores, flushing & severe sweating, hair loss
- Allergy symptoms: odd reactions to insect stings, reactions to fragrances, allergic reactions to medications, food allergies, anaphylactic reactions, inflammation, and swelling
- Persistent fatigue: insomnia, unrefreshing sleep, unexplained weakness, shortness of breath
- Immune symptoms: recurring infections, enlarged lymph nodes
- Joint or bone symptoms: decreased bone density
- Cardiovascular symptoms: tachycardia (racing heart), sudden drops in blood pressure
- Neurological symptoms: cognitive impairment, numbness & tingling in face and extremities, skin feels on fire, unexplained anxiety, temperature (hot/cold) sensitivity, vertigo, fainting
- Vision problems: watery eyes, dry eyes, sunlight sensitivity
- Hormonal symptoms: difficult menses (females), thyroid problems
- Pain: headaches, migraines, persistent body/tissue pain, chest pain, gastrointestinal pain, liver pain, kidney/bladder pain, neuropathic pain, eye pain
- Digestive symptoms: persistent diarrhea, IBS, nausea, vomiting, bloating, SIBO, enlarged liver/spleen, unexplained Vitamin B12 deficiency, anemia, unexplained weight loss
- Urinary tract symptoms: frequent urination, pain/burning
Other symptoms may include difficulty exercising and even reactions to heat, cold, and vibration, like from mowing the lawn.
How is Histamine Intolerance Different from a Food Allergy?
Histamine intolerance differs from a food allergy in that food allergies may still stimulate the release of histamine but for the most part, the body is able to break it down. With histamine intolerance, there’s a problem in breaking down histamine, which causes it to build up to high levels.
A person can be unable to break down histamine due to a lack of certain enzymes in the body, like diamine oxidase (DAO) and histamine N-methyltransferase (HNMT). DAO mostly breaks down histamine in the gut, and HNMT mostly breaks down histamine outside the gut.
It’s kind of like how lactose intolerance is different from a dairy allergy. Those with lactose intolerance lack the ability to break down lactose.
How Are MCAS and Histamine Intolerance Assessed?
Only recently has mainstream medicine begun to recognize these conditions. These are some lab tests that may be done to identify high histamine levels.
- Histamine Plasma: This tests the level of histamine currently in your blood. (Not accurate, as it goes up and down for its many functions)
- DAO (Diamine Oxidase) test: As mentioned just, DAO is an enzyme that degrades histamine, so low levels may indicate high histamine. However, DAO is only one of the two histamine-degrading enzymes, so this test may not give a full picture.
- Histamine Skin Prick Test: This test evaluates histamine issues by injecting patients with pure histamine to see whether it causes a significant reaction. However, false negatives occur.
These tests can give some idea of whether histamine levels are high, or whether a dis-ease process is taking place. However, that’s only the first step. Next, it’s time to determine what can be done for the chronic inflammation and to restore the gut lining and microbiome.
The Fireman vs. The Carpenter in Healthcare
At The Wellness Way, we describe the mainstream viewpoint on healthcare versus our understanding and methods as the “fireman approach” or the “carpenter approach.”
Mainstream “fireman” doctors have two tools: an axe and a hose. The axe represents cutting things out in a surgical procedure. The hose represents using medications to extinguish inflammation, pain, and other symptoms.
The Wellness Way doctors are like carpenters. They assess the damage with testing and then create a personalized plan to rebuild the body with the required nutrients from foods and supplements. Sunshine, rest, and positive relationships are additional natural therapies that help with healing.
Mainstream Medicine’s Approach to MCAS and Histamine Intolerance
Mainstream medicine looks at MCAS and histamine intolerance as genetically determined conditions.
Common Medications For MCAS and Histamine-Related Symptoms
Here are some of the most prescribed medications for MCAS, histamine intolerance, and other histamine- or allergy-related symptoms:
- H1 Antihistamine drugs: Diphenhydramine (Benadryl), Loratadine (Claritin), Fexofenadine (Allegra), Cetirizine (Zyrtec)
- H2 Antihistamine drugs: Famotidine (Zantac), Cimetidine (Tagamet)
- Mast cell inhibitors/leukotriene modifiers: Montelukast (Singulair)
- Corticosteroids: Prednisone
- IgE blocker drugs: omalizumab (Xolair)
- Mast cell stabilizers: Cromolyn cromolyn sodium (Gastrocrom)
These medications suppress histamine and the inflammatory response, so they usually help with symptoms. However, suppressing the immune response over time isn’t healthy. Eventually, suppressing the immune system can lead to other conditions, like cancer. Like all pharmaceutical drugs, these meds also have side effects. There’s definitely a better way.
What Causes MCAS and Histamine Intolerance? Trauma, Toxins, & Thoughts
At The Wellness Way, we know there are several contributing factors to any dis-ease. There’s rarely one “root cause.” Addressing these contributing factors naturally can allow the body to heal itself. Here are the three categories of stressors, as originally described by the chiropractic field: Traumas, Toxins, and Thoughts.
Traumas (Physical Stressors)
Traumas or physical stressors can be acute or chronic. Chronic subluxations in the spine can inhibit nerve and blood flow to the small intestine, leading to dysbiosis, leaky gut, and chronically triggered mast cells. Other potential traumas behind MCAS include:
- Neck injuries
- Sexual assault/rape
- Car accident
- Severe illness or infection
- Witnessing violence or a natural disaster
- Military combat – PTSD
- Having a baby
- A death in the family or a close friend
Physical traumas and the potential of chiropractic care should not be underestimated. Researchers have found that chiropractic care and spinal manipulation can help to calm the nervous system, taking the body out of fight-or-flight and allowing it to heal. 
Toxins (Biochemical Stressors)
Toxins are biochemical stressors that may be either natural or synthetic. Toxins associated with MCAS include:
- Mold toxicity – Molds have been known to activate mast cells and are one of the top causes of MCAS. 
- Lyme and related pathogens – Lyme spirochetes have been shown to trigger mast cell activation and the release of inflammatory cytokines. 
- COVID-19 – Long haul COVID may actually be MCAS. 
- Heavy metals – Toxic metals, even from dental materials, can also stimulate histamine release from mast cells. 
- Toxic chemicals – One single exposure could set off MCAS, or it could result from multiple exposures over time. Examples include pesticides, smoke inhalation, or volatile organic compounds (VOC) from building materials.
- Food allergies – Eating foods you’re allergic to stimulates mast cells to release histamine and other inflammatory mediators. 
Keep in mind that most infections are opportunistic, meaning they are more likely to occur if the body is already compromised by toxins like heavy metals and chemical exposures. Traumas and toxins are made worse by negative thought patterns and emotional stress.
Thoughts (Emotional Stressors)
Emotional stress is a significant contributor to MCAS and histamine intolerance. Continuing to stay in a stressful situation can make it very difficult to heal. Here are some contributors to emotional stress or negative thoughts, which may lead to chronic illness:
- Watching or reading the news (fear/worry)
- Emotional stress from marriage, financial, career, or other issues
- A state of overwhelm by major life changes, such as marriage, a new baby, graduation, divorce, or even moving to a new city.
- Grief/feelings of loss
- Pent up anger
The Wellness Way Approach to MCAS and Histamine Intolerance
At The Wellness Way, we dig deeper to solve the health challenges others can’t. We start with testing to see where there may be imbalances and then develop a personalized nutrition and supplement plan to help your body heal itself.
Important Tests For Assessing Your Gut and Immune Health:
With MCAS and histamine intolerance reducing inflammation has to be the first goal. Inflammation in the brain and gut aggravate all symptoms of these conditions. Here are some tests Wellness Way practitioners may use for MCAS and histamine intolerance symptoms:
- Food Allergy Test: Immuno Food Allergy Test
- Gut Health Test: Genova GI Effects with Parasitology
- Immune Panel: Access Custom Immune Panel
- Hormone Panel: Male Hormone Panel or Female Hormone Panel
The recommended testing will depend on your Wellness Way practitioner, and which tests he or she considers most important based on your symptoms and health history.
Dietary Changes For Those With MCAS and Histamine Intolerance
The most important thing for MCAS and histamine intolerance is to lower overall inflammation in the body. That means following a personalized nutrition program, as recommended by your Wellness Way practitioner. Beyond avoiding your food allergies, the personalized nutrition program will likely also recommend eating a low histamine diet. Here are some additional guidelines for inflammatory and high histamine conditions:
- No sugar or processed foods – Both increase inflammation. Certain additives used in processed food, such as carrageenan,  maltodextrin, sulfates, and guar gum, may set off mast cells, triggering symptoms.
- No cow’s milk dairy products – Goat and sheep’s milk products may be better tolerated –and even beneficial. 
- Gluten-free, overall grain-free – Gluten aggravates the gut lining, causing inflammation and a release of histamine. 
- Avoid high omega-6 vegetable oils, like corn, canola, soybean, cottonseed oil, sunflower, grapeseed, and others, which can alter the omega-6 to omega-3 balance to be more inflammatory. 
- Consume an overall low carbohydrate, non-inflammatory diet of organic whole foods.
- Consume an overall low histamine diet – While you’ll find variations on which foods are high or low histamine, the highest histamine foods you’ll want to avoid are alcoholic beverages, fermented foods like sauerkraut and pickles, and aged foods (cheeses, sausages, and cured meats). There are also histamine-releasing foods like strawberries, citrus, tomatoes, peanuts, and chocolate. 
- Follow a Personalized Nutrition Program, based on your food allergy test results. Avoiding your food allergens is critical for lowering inflammation and histamine. Including naturally-antihistamine foods, like onions, chickpeas, ginger, and arugula may also be helpful.
- Include nutrient-dense foods: Liver/organ meats and microgreens add nutrition.
Diet is the most important change you can make, but supplements can help. Specifically, selected herbs and supplements can help balance the immune response and heal the digestive tract.
Supplements For Supporting Gut Health + Balancing The Immune Response
Each person is different, but supplements often used at The Wellness Way for those struggling with histamine intolerance and mast cell issues include the following:
- Albizia – Albizia herb has a strong anti-inflammatory and antihistamine effect that may help the body address high histamine and mast cell activation. 
- Chamomile – This herb is high in phenolic compounds that can help lower inflammation and reduce histamine release 
- Ginkgo Leaf – Ginkgo biloba is rich in an antihistamine compound called quercetin. 
- Japanese Knotweed – This excellent source of resveratrol is being researched for its ability to prevent mast cell activation and subsequent mediator release. 
- Licorice – Licorice root can provide natural antihistamine support, as it works on H2 histamine receptors. 
- Milk Thistle – A natural mast cell stabilizer, milk thistle also supports liver and gallbladder detoxification. Silymarin, an extract of milk thistle, has been shown to reduce anaphylaxis-like reactions. 
- Nettle Leaf – Nettle reduces the release of inflammatory messenger chemicals from mast cells, which may lessen allergic symptoms. 
- Rehmannia – “Nature’s corticosteroid”? Rehmannia is very supportive of a balanced immune response. It improves the gut bacterial balance and strengthens the gut lining. 
- Turmeric – Curcumin, the main active constituent in turmeric, has anti-inflammatory properties that may help lower the allergenic response. 
- White Peony – This herb has long been used in Traditional Chinese Medicine for asthma. Research has found it works as a mast cell stabilizer, inhibiting histamine release. 
- DAO enzyme – This enzyme breaks down histamine. Supplementing with DAO sourced from a kidney glandular may help lower histamine levels.  Our Blood Sugar Glandular contains kidney glandular tissue.
- Vitamin C – Vitamin C can also serve to lower histamine, as it’s needed for the body to produce DAO. When vitamin C levels are too low, histamine quickly increases. However, it’s important to find a vitamin C source that’s not made by fermentation or derived from corn or citrus. Plant-based sources, like amla, acerola, rose hips, or camu camu may be best.
- Probiotics – Megabiotic Powder may support an ideal microbial balance in the gut.
- Prebiotic – Chicory Root Inulin and other prebiotics can feed good bacteria in the gut, improving the balance of the gut microbiome and promoting a healthy mucus lining in the intestines. Addressing dysbiosis can help reduce reactions and promote immune system balance. 
Everyone is different – what works for one person may not work for another. Part of that is due to body chemistry, genetics, and allergenic responses to different botanicals.
Lifestyle Changes & Complementary Therapies For MCAS and Histamine Intolerance
- Regular chiropractic care – Chiropractic care helps improve blood flow and nerve flow while decreasing overall physical stress on the body.
- Yoga – Yoga and Pranayama have also been shown to lower histamine and inflammation 
- Limbic system retraining – Brain retraining via the Gupta program or Dynamic Neural Retraining System (DNRS) may help calm mast cells.
Anything that helps lower the stress response will be helpful for MCAS and histamine. This may mean taking a walk in a beautiful place, meditating, watching comedies, playing music, or making time for the things you enjoy.
Educational Resources For Inflammation & Allergies
Be a well-informed patient! Here are some resources for learning more about inflammation and allergy-related conditions.
Videos & Webinars Related to MCAS, Histamine Intolerance, and Allergies
Articles to Support Those With MCAS, Histamine Intolerance, and Allergies
- Environmental Allergies: Why Are You Reacting to Everything? – The Wellness Way
- Allergies Are at Epidemic Level! – Are We Overreacting? – The Wellness Way
- What Causes Leaky Gut and How Can You Heal It?
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- Histamine and histamine intolerance – ScienceDirect
- Neurobiological basis of chiropractic manipulative treatment of the spine in the care of major depression – PMC (nih.gov)
- Impact of mold on mast cell-cytokine immune response – PubMed (nih.gov)
- Borrelia burgdorferi spirochetes induce mast cell activation and cytokine release – PubMed (nih.gov)
- COVID-19, Mast Cells, Cytokine Storm, Psychological Stress, and Neuroinflammation – PubMed (nih.gov)
- Metal ion-induced toxic histamine release from human basophils and mast cells – PubMed (nih.gov)
- Mast cells may explain chemical intolerance – IDSS (mit.edu)
- Mast Cells as Regulators of Adaptive Immune Responses in Food Allergy – PubMed (nih.gov)
- Re-appraisal of the role of histamine in carrageenan-induced paw oedema – PubMed (nih.gov)
- Goat milk is less immunogenic than cow milk in a murine model of atopy – PubMed (nih.gov)
- Intestinal Mucosal Mast Cells: Key Modulators of Barrier Function and Homeostasis – PubMed (nih.gov)
- The importance of the ratio of omega-6/omega-3 essential fatty acids – PubMed (nih.gov)
- Anti-inflammatory activity of Albizia lebbeck Benth., an ethnomedicinal plant, in acute and chronic animal models of inflammation – PubMed (nih.gov)
- Anti-allergic activity of German chamomile (Matricaria recutita L.) in mast cell mediated allergy model – ScienceDirect
- Ginkgo – PubMed (nih.gov)
- Resveratrol Attenuates Mast Cell Mediated Allergic Reactions: Potential for Use as a Nutraceutical in Allergic Diseases? – PubMed (nih.gov)
- Anti-pseudo-allergic components in licorice extract inhibit mast cell degranulation and calcium influx – PubMed (nih.gov)
- Silibinin attenuates mast cell-mediated anaphylaxis-like reactions – PubMed (nih.gov)
- Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis – PubMed (nih.gov)
- Rehmannia glutinosa polysaccharides attenuates colitis via reshaping gut microbiota and short-chain fatty acid production – PubMed (nih.gov)
- Therapeutic potency of curcumin for allergic diseases: A focus on immunomodulatory actions – PubMed (nih.gov)
- Total glucosides of peony improve ovalbumin-induced allergic asthma by inhibiting mast cell degranulation – PubMed (nih.gov)
- Diamine oxidase supplementation improves symptoms in patients with histamine intolerance – PMC (nih.gov)
- Studies with inulin-type fructans on intestinal infections, permeability, and inflammation – PubMed (nih.gov)
- Effect of yoga breathing exercises (pranayama) on airway reactivity in subjects with asthma – PubMed (nih.gov)