What are Mast Cell Activation Syndrome (MCAS) and long Covid-19 GI problems
You may have heard of long COVID-19, but are you familiar with mast cell activation syndrome? They share similar symptoms that affect our gastrointestinal system. If you are experiencing these symptoms, it’s worth investigating further.
What is the link between long Covid-19 and Mast cell activation syndrome?
Around 65 million people globally are dealing with long COVID-19, mainly aged 36–50. Those with long COVID-19 experience multiple organ dysfunctions, long-term organ damage, and reduced quality of life. Risk factors for long COVID-19 overlap with other post-viral syndromes so that research advances could benefit other patient groups. Long COVID-19 results from immune system disruptions like T-cell depletion, overactive innate immune cells, lack of naive T and B cells, and high levels of pro-inflammatory cytokines. It also involves persistent severe acute respiratory syndrome-coronavirus 2 and other effects of acute infection. Mast cells in long COVID-19 are unusually active, with abnormal granulation and excessive inflammatory cytokine release. Weinstock et al.’s study suggests that long COVID-19 patients and mast cell activation syndrome (MCAS) patients experience the same clinical syndrome. Diagnosing and treating MCAS in long COVID-19 patients could provide additional symptom relief and manage hyperinflammation, aiding long-term control and recovery.
The pathway of activation of the mast cell
Long COVID-19 is thought to result from multiple pathophysiological mechanisms following initial acute infection. Firstly, systemic inflammatory response syndrome leads to tissue injury and organ dysfunction. The COVID-19 immune response releases numerous pro-inflammatory cytokines. This can cause a cytokine storm and severe COVID-19 in some people, but most will experience an anti-inflammatory response leading to immune homeostasis. Mast cells, part of the immune system, are involved in immediate allergic responses. As in MCAS, various factors can trigger these cells, including mast cell clonal disorders, allergies, neoplastic conditions, physical and autoimmune urticaria, and idiopathically. MCAS involves mast cell overactivity and excessive chemokine release (histamine, tryptase, carboxypeptidase A, and chymase). MCAS can affect the cardiopulmonary, gastrointestinal, dermatological, and neurological systems.
What will you feel? Especially in your gut?
Episodic symptoms consistent with mast cell mediator release affecting two or more organ systems are evidenced as follows:
- (a) Skin: urticaria, angioedema, flushing
- (b) Gastrointestinal: nausea, vomiting, diarrhea, abdominal cramping
- © Cardiovascular: hypotensive syncope or near syncope, tachycardia
- (d) Respiratory: wheezing
- (e) Naso-ocular: conjunctival injection, pruritus, nasal stuffiness.
According to Gastro and Mast Cell Connection, Gastrointestinal symptoms often start due to mast cell reactions or histamine intolerance to certain foods and additives. These symptoms can range from mild to severe, leading to bloating, rashes, diarrhea, constipation, and changes in mood and behavior. Over time, this reaction can harm the gut and contribute to inflammation elsewhere in the body. Additional gastrointestinal complications can arise from issues with movement and instability in the internal organs.
High histamine levels can lead to symptoms like skin rashes, digestive issues, rapid heartbeat, and neurological problems. Symptoms are usually managed with medication and a low-histamine diet if this occurs.
Treatment recommendation
Medication
Typically, MCAS is managed with antihistamines, mediator synthesis inhibitors, mediator release inhibitors, and mast cell degranulation inhibitors. The foundation of the treatment is the H1 receptor blockers, which use a mix of nonsedating (like cetirizine and loratadine) and sedating (such as diphenhydramine and doxepin) agents. Combining with H2 antihistamines (like ranitidine and famotidine) can help block histamine receptors and relieve gastrointestinal symptoms.
Reducing mediator release with sodium-cromoglycate and ketotifen can help skin, gastrointestinal, and neuropsychiatric symptoms. Mediator synthesis inhibitors like aspirin, montelukast, and zileuton can also work together. Aspirin and other Nonsteroidal anti-inflammatory drugs shouldn’t be avoided if the patient has tolerated these medications previously once MCAS has been diagnosed.
Diet
Some individuals with Long COVID-19 may develop a sensitivity to histamine in food. This could be due to elevated histamine levels during inflammation or difficulty processing dietary histamine. Currently, there is no proven evidence that a low histamine diet benefits the majority of people with Long COVID-19, though some have found it beneficial.
Do not confuse low histamine with a Mediterranean diet or anti-inflammatory diet.
A low histamine diet requires a 2 to 4-week trial period. During this time, foods high in histamine are restricted. After this period, these foods are reintroduced systematically to assess tolerance.
The following foods contain higher levels of histamine and should be avoided:
- fermented dairy products, such as cheese (especially aged), yogurt, sour cream, buttermilk, and kefir
- fermented vegetables, such as sauerkraut and kimchi
- pickles or pickled veggies
- kombucha
- cured or fermented meats, such as sausages, salami, and fermented ham
- wine, beer, alcohol, and champagne
- fermented soy products such as tempeh, miso, soy sauce, and natto
- fermented grains, such as sourdough bread
- Yeast Extract (yeast itself as an ingredient is OK)
- tomatoes (green tomatoes are OK)
- eggplant
- spinach
- frozen, salted, or canned fish, such as sardines and tuna
- Avocado
- Cherries
- vinegar
- tomato ketchup
For details, please visit Oshi Health
Limit foods with histamine-releasing capacities:
- Certain spices: cinnamon, cloves, anise, nutmeg, curry powder, chili powder
- Foods preserved with sulfites, like dried fruit, frozen potatoes, red wine
- Foods preserved with BHA or BHT (e.g., some breakfast cereals)
- Baked goods that contain bleached flour (commercial breads and pastries)
- Foods that contain artificial food coloring, especially tartrazine (FD&C Yellow #5)
For details, please visit Oshi Health
Minimize or eliminate alcohol. Alcohol hinders the enzyme that processes histamine.
- Particularly red wines (due to their high histamine levels and sulfite content)
- White wines
- Beer
As food ages, proteins naturally degrade. Histadine, a protein component, breaks down into histamine, which can cause issues for those sensitive to histamine. Avoid consuming high-protein “leftovers,” such as meats, poultry, beans, and dairy to manage symptoms. Leftover low-protein foods like grains, fruits, and vegetables are less problematic. Monitor your symptoms and adjust your diet as needed.
According to Oshi Health:
So what CAN you eat on a low-histamine diet?
Low histamine fruits
- Apple
- Banana
- Blueberries
- Coconut
- Dragon fruit
- Kiwi
- Guava
- Melons (all)
- Mango
- Peaches
- Pear
- Starfruit
- Lychees
- Figs
- Rhubarb
- Juices or jams made from any of these fruits that do not contain sulfites as a preservative
Low histamine veggies
- Asparagus
- Beets
- Broccoli
- Brussels sprouts
- Carrots
- Cauliflower
- Cabbage
- Cucumber
- Lettuce
- Green beans
- Corn
- Kale
- Peppers
- Zucchini
- Onion
- Garlic
Low histamine proteins
- Eggs, fully cooked (especially yolks)
- Fresh meat, chicken, turkey (avoid leftovers)
- All legumes EXCEPT chickpeas, lentils, red beans and soybeans/tofu
- Individually quick frozen fish fillets
- Uncultured cheeses: cottage cheese, cream cheese, ricotta, mascarpone, Indian-style “paneer” cheese, fresh mozzarella
- Plain milk, fresh cream (watch out for spoilage)
- All plain/salted nuts and seeds EXCEPT pumpkin seeds
- Natural nut butter (no preservatives)
- Sunbutter
- Plain or vanilla protein powders with no added colors, sweeteners, or preservatives: Jarrow brown rice/hemp or Nutribiotic rice protein
Low histamine grains/ starches
- Potato and sweet potato (fresh. Avoid frozen potato products/French fries due to likely sulfite content.)
- Corn, popcorn
- Rice (all varieties), rice cakes, rice crackers
- Bread, crackers, and baked goods made with unbleached white flour (e.g., organic) or whole wheat flour
- Plain pasta
- Couscous
- Homemade biscuits or scones that use baking soda/powder as a leavener also known as a raising agent or leaven, and unbleached flour
- Whole grain crackers that do not contain yeast or preservatives (e.g., Wasa, Triscuits)
- Whole wheat or organic white bread, buns, etc. that do not contain prohibited preservatives or similar gluten-free alternatives
- Plain cereals such as cornflakes, shredded wheat, rice cereal, oats/oatmeal, cream of wheat, and cream of rice
- QuinoaBuckwheat (kasha, soba noodles)
- Millet
Low histamine seasonings
- Oil, ButterSalt/pepper
- HerbsAll spices not listed under prohibited
- Onion/garlic, scallions, chivesSugar, maple syrup, honey, corn syrup
Low histamine beverages
- Milk
- Coffee
- Many herbal teas (no zingers or zests)
- Juice/nectars made from approved fruits
- Club soda
- Among alcoholic drinks, vodka or gin is most likely to be tolerated
Low histamine treats/ sweets
- More natural vanilla ice creams with short ingredient lists (Ciao Bella, Haagen Dazs)
- Homemade or more natural chocolate chip cookies and cakes made with unbleached flour, real butter, sugar, eggs, etc.
A low-histamine diet can lead to malnutrition, given its restrictive nature.
Histamine intolerance is not well understood and is hard to diagnose. Without a confirmed diagnosis, there’s no proof that a low-histamine diet improves life quality in the long term.
The main advantage of a low-histamine diet is its use as a diagnostic tool.
A doctor-supervised elimination of histamine-rich foods from your diet for several weeks, followed by a slow reintroduction, can provide insights into your tolerance to histamine-rich foods.
Histamine tolerance can greatly differ among individuals. Reintroducing histamine into your diet enables you to identify which foods cause symptoms.
References:
Oshi Health — low histamine diet
Ramsay, D. B., Stephen, S., Borum, M., Voltaggio, L., & Doman, D. B. (2010). Mast Cells in Gastrointestinal Disease. Gastroenterology & Hepatology, 6(12), 772–777. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033552/
Sumantri, S., & Rengganis, I. (2023). Immunological dysfunction and mast cell activation syndrome in long COVID. Asia Pacific Allergy, 13(1), 50–53. https://doi.org/10.5415/apallergy.0000000000000022
Weinstock, L. B., Brook, J. B., Walters, A. S., Goris, A., Afrin, L. B., & Molderings, G. J. (2021). Mast cell activation symptoms are prevalent in Long-COVID. International Journal of Infectious Diseases, 112, 217–226. https://doi.org/10.1016/j.ijid.2021.09.043
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