The Best Mast Cell Activation Syndrome (MCAS) Supplements & Diet: 3 Steps to Calm a Flare

Written By


Expert Reviewed By

Dr. Lauryn Lax, OTD, MS

Dr. Lauryn, OTD, MS is a doctor of occupational therapy, clinical nutritionists and functional medicine expert with 25 years of clinical and personal experience in healing from complex chronic health issues and helping others do the same.

Mcas Supplements - Various Kinds Of Mcas Supplements

Mast Cell Activation Syndrome can make you sensitive to seemingly everything—foods, supplements, heat, cold, smells, sounds, even water! 

So what is the best MCAS supplements and diet? Look no further than these 3 steps to learn how to progressively calm down an MCAS flare when it strikes. 

3 Steps to Calm Down a MCAS Flare: MCAS Supplements, Diet, and Lifestyle Hacks 

Step 1: Establish a Foundation & Immune Stability

Step 1 is essential if you are highly reactive and stuck in the cell danger response (ie. Sensitivities to seemingly EVERYTHING). Some people will need more time than others. Listen to your body and don’t move to Step 2 until you are not so reactive to “everything.” 

MCAS Supplements

Mast Cell Stabilizer: Quercetin (250-500 mg, 20-30 min before each meal, 1 at  bedtime)

H1 Blocker (Histamine Blocker): Claritin, Allegra or Zyrtec (10 mg at bed time)

H2 Blocker (Histamine Blocker): Famotidine (like Pepcid), 20 mg at bedtime, Singular

*Note: Before beginning any new supplements or medications, discuss your treatment with your healthcare provider.


Mcas Supplements - Various Kinds Of Mcas Supplements

Consider trying a low histamine diet for 2 weeks to see how you feel. By limiting histamines in the diet, you inhibit the overabundance of histamine in the body.

If symptoms improve, continue following the low-histamine diet for 1 to 6 months; however, if you notice no difference, then stick to a low-allergen, anti-inflammatory  autoimmune paleo die template for the same time frame. 


Optimize anti-histamine foods that help calm down the cytokine storm happening inside, including:

  • Natural H1 blockers: cilantro, basil, thyme, ginger, onion, mangosteen, nigella sativa
  • Natural H2 blockers: holy basil and ginger

MCAS Lifestyle Hacks

  • Move It, Move It: Cut back on training; walking, yoga and anything that leaves you feeling better, not worse. Give yourself permission to not ‘kill yourself’ in the gym.
  • Get Your Beauty Sleep: Emphasize adequate rest; cut screen exposure in evenings and use blue blocker glasses to candle down at night.
  • Just Breathe: Breath is the #1 weapon for calming down the stress response. Try: Sea salt inhaler or Olba’s inhalers (peppermint); Insight Timer meditation app; Deep breathing; Fresh air; Sleep with an air purifier on your head to circulate air.
  • Try Lifestyle Therapies. If you can’t tolerate supplements right now, consider trying lifestyle immune stabilizing therapies like infrared sauna, fresh air, yoga and meditation.

Step 2: Boost Immunity

Continue building upon Step 1 with some more immune stabilizing “boosters” aimed at calming down histamine response.

MCAS Supplements

  • DAO digestive enzymes (Recommendation: Histamine Block, order on FullScript Store; 1-2 capsules with meals)
  • Digestive enzymes with meals (if tolerated): (Recommendation: Holozymes)
  • Mast Cell Stabilizers: Add in 1-2 different natural mast cell stabilizers taken 30 minutes before a meal with quercetin; start with 1 capsule and gradually work up to 2 capsules with meals.
    • Recommendations (find on the FullScript Store unless indicated)
    • Additional H1-H2 Histamine Blocker: Once natural anti-histamines are up and running with food, incorporate an additional H1-H2 Histamine Blocker if needed. Options: Additional dose of Claritin, Allegra or Zyrtec—10 mg during the day

*Note: Before beginning any new MCAS supplements or medications, discuss your treatment with your healthcare provider.


  • Incorporate Variety.

Continue with your low histamine and/or autoimmune paleo diet with a BIG focus on ensuring diversity and variety on your plate. When we eat the same things every single day, we foster a non-diverse microbiome and continued suppressed immune system. Even if “diversity” means eating a purple or yellow carrot, instead of an orange carrot. The healthier your gut, the stronger your immune system.

  • Have No Fear.

ARFID (avoidant restrictive food intake disorder) is common in those with MCAS, based upon former negative experiences with all sorts of foods (such as an episode of reactive hypoglycemia after eating a sweet potato, stomach cramps after eating an apple or tongue swelling after eating sunflower seed butter). As a result, many people’s diets become super limited to 5-10 foods out of fear of how foods make them feel. Speak nourishment and healing into your body during meal times, and just because you reacted negatively in the past to certain foods, the more you focus on healing from the inside out, the more you will have freedom to expand your diet. Trust the process.

  • Don’t Forget Your Anti-histamines with Meals.

To help with food toleration, take your mast cell stabilizer agents of choice along with DAO and/or digestive enzymes with each meal. You will get stronger over time.

MCAS Lifestyle Hacks

Mcas Supplements - Woman Cutting Negativity And Just Relaxing

  • Cut the Negatives. What we focus on expands. Promote a growth mindset to allow more room for healing (and less stress) in your body. Fact: 95% of our thought life is lived in the subconscious. And, considering the direct link between the gut and the brain, the more stressed your brain, the more stressed your gut, and the more stressed and over-active your immune system. Unfollow non-edifying social media accounts, cut the news, limit your exposure to negative people/relationships, etc. Replace it with affirmations, meditations, devotionals, books and growth.
  • Humans are nutrients. Research shows a huge decrease in immunity when people are socially isolated. Make a point to stay in touch with friends, family or consider getting a pet.

Step 3: Love Your Gut & Retrain Your Brain

With a more stabilized immune system in place, you can now focus more heavily on the gut and brain axis that is driving immune system dysregulation and MCAS flares in the first place! 

MCAS Supplements

Mcas Supplements - Different Kinds Of Mcas Supplements On Spoons

Gut Supports

Support the gut with these 5 gut healing essentials:

  • Trace mineral drops (Recommendation: Spectramin by Energetix)
  • Short Chain Fatty Acids with meals (Recommendation: Tributyrin-X)
  • Digestive enzymes with meals (like Holozymes)
  • Histamine-degrading probiotic, (Recommendations: Bifido Maximus or CT Spore BY Cell Core —use code PJ03HABY to place order)

Brain Supports

Calm the ‘stress’ response with HPA Axis support like:


As your immune system stabilizes, the goal is that you can begin broadening your dietary options and trying more nutrient-dense foods again in order to foster a healthier microbiome for a stronger immune system. This is a sign of “improved oral tolerance.”

A varied diet is essential for a healthy biome—even if that variety looks like eating both orange and purple carrots, different types of healthy fats—ghee, extra virgin olive oil, coconut, or being able to tolerate apples, salmon, kale or sweet potatoes again that once made you “flare.”

While you may have some “PTSD” from former experiences with foods during your most heightened MCAS flares, try to keep an open mind with nutrient dense foods. You ARE healing and you don’t have to stay stuck eating only 5 to 10 foods forever.

MCAS Lifestyle Hacks

Retrain the Limbic System & Vagus Nerve

You will not fully heal until you calm down the limbic system and strengthen your vagus nerve (brain-gut connection as well as autonomic nervous system stability).

Limbic System Retraining Resources

Vagus Nerve Exercises

  • Coffee enemas + holding or “planking” for 10-15 minutes before releasing
  • Gag reflex exercises (say “ahhhhh” with a tongue depressor)
  • Gargling water for 50-60 seconds per swig, 2-3 times per day
  • Relaxation (yoga, deep breathing, meditation)
  • Tapping (EFT)
  • Read: Vagus Nerve Books: Accessing the Healing Power of the Vagus Nerve & Activate Your Vagus Nerve


There is no one-size-fits-all for recovering from Mast Cell Activation Syndrome. However, keep this hope in mind: when given the right tools, the body wants to innately heal itself. Try these MCAS supplements and MCAS diet and lifestyle strategies to help ‘calm the flares’ and trust in the process—you are doing everything you can to help bring your body back to peace and calm.

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