Meg Mill

Histamine and Mast Cell Acitvation Syndrome

Aired On: Sep 26, 2025

Show Notes

Histamine is a crucial compound in the body and is involved in many vital processes. When histamine levels are not balanced, it can trigger a cascading effect on multiple systems, leading to a dizzying array of symptoms that appear unrelated.  Migraines, anxiety, digestive distress, skin issues, menstrual pain, palpitations, brain fog, mood dysregulation, arthritis, etc.

Meg Mill is a Functional Medicine Practitioner and clinical pharmacist specializing in the often-overlooked intersection of gut health, hormone balance, and nervous system regulation, with a unique focus on neuro-digestion—the intricate connection between the brain, gut, and immune response. In her virtual Functional Medicine practice and her Women’s Wellness Collective, she has guided hundreds of people to uncover the root causes of fatigue, hormonal chaos, digestive dysfunction, and unexplained symptoms. 

Dr. Meg is also a bestselling author and host of the top-rated A Little Bit Healthier podcast. Her work has been featured in many national news outlets, such as Forbes Health, Fox News, and MindBodyGreen. Her mission is to help women reclaim their health, energy, and mental clarity so they can feel energized, confident, and comfortable in their bodies

Histamine and mast cells

Meg MIll

  • www.megmill.com
  • Podcast a little bit healthier
  • Histamine deactivation program megmill.com/histamine
  • Instagram. Drmegmill
  • Essential guide to histamine intolerance

Over half of us have chronic diseases

We aim for optimal health, not average health

Histamine

  • Purpose of histamine bioaientic amine
  • When immune system detects an invader, the mast cells release histamine which
    • Increases permeability of blood cells, allowing immune cells to reach infected site or site of injury  more quickly
    • Protects against pathogens
    • Increasing acid secretions to break down food
    • Can affect neurotransmitter activity
    • Is part of allergic response  and is part of inflammatory response
  • Contributes to inflammation contributing to oxidative stress contributing to every chronic illnesses

Mast cells are located in the innate immune system and are  front line responders

  • They do not respond to specific insults as does the adaptive immune system
  • Is good in an acute situation but not when released chronically

Pathways Processing histamines

  • Two different pathways
    • Diamine oxidase breaks food down in the gut
      • Altered by genetic variation, dysbiosis, gut mucosa
    • Methyl transferase
      • If we are not methylating well, we are not breaking down histamines

How this affects us

  • There are histamine receptors throughout the body and overlaps with many other things
    • Hypersensitivity: nasal congestion, sneezing, itching, congestion, hives, asthma
    • Headaches, Migraines, Fatigue, heart palpitations, dizziness, anxiety
    • Difficulties concentrating, irregular periods, worsening PMS symptoms
    • Flushing, joint pain,
    • Insomnia nighttime wake ups with histamine dumping
    • Changes in blood pressure, dizziness
    • GI symptoms: IBS,
    • Chemical sensitivities big sign of histamines and mast cells
      • Range from feeling bothered, I can’t tolerate anything
      • Mast cells can become overreactive and react to things they should not react to
    • Contributing factors
      • If have h pylori, candida, parasites
      • There are mast cell producing bacteria in the gut
      • Mould exposure tick borne illnesses, chemical exposures
  • Triggering histamine response/ overactivation of mast cells
    • Mould , mycotoxins, gut dysbiosis, SIBO,
    • Infections Lyme, bartonella ,viruses
      • More prevalent after covid as covid virus put people “over the edge”
      • Chemicals, toxins,  personal hygiene products, pesticides, chemicals in food  
      • EMF
      • Hormonal changes
        • mast cells have estrogen receptors
        • Estrogen will increase mast cells to release histamines
        • Progesterone helps break down histamine
          • Helps diamine oxide to break down mast cells
      • Healthy foodscontaining histamines,  avocados, tomatoes , strawberries, bananas, fermented foods, bone broth, probiotics

Mast cell activation v histamine intolerance

  • Histamine intolerance refers to the overall histamine load
  • Histamine intolerance occurs when we produce more histamines than we break down
  • Can have histamine intolerance without mast cell activation
  • Mast cell activation
    • Is a diagnosis but sometimes is hard to diagnose
      • Have to go by the symptoms
    • With mast cell activation, will have a lot of symptoms similar to histamine intolerance as mast cells release histamines
    • Mast cell activation caused by issues listed about in overactivation of mast cells
  • What to do
    • Goal   
      • bring body back into balance
      • increase food tolerance and
    • Bring the body back into balance so can process histamines
    • Look at gut health and gut mucosal layers,
    • adequate digestive enzymes
    • hormones are balanced
    • ensure we are methylating well
      • can measure with homocysteine or blood vitamin B nutrients
      • if starting vitamin Bs make you feel worse, you need to look at specific pathways
      • sometimes need to start with a specific vitamins such as vitamin B1 due to specific pathways
      • careful of folic acid as with a poor MTHFR snp, folic acid can accumulate in the body which has been associated with certain pathways
    • ensure have adequate needed nutrients
    • work on nervous system regulation
      • sometimes nervous system is dysregulated for example having a negative reaction to a benign object (the danger response
      • look at somatic responses
        • limbic system work
          • thought reframing changing thought patterns and increasing neuroplasticity
            • when body is perceived to be in danger, these patterns need to be replaced
        • vagus nerve retraining
          • make sure gut and brain area communicating well
          • bring body back into parasympathetic nervous system
        • take two minutes three times per day, and start doing belly breathing (breath from belly, hold it for a couple of seconds)
          • can feel body calming down
        • we need to believe we can heal
      • supplements            
        • mast cell calming     quercetin, rhodiola
        • immune supplement support
        •  
      • detox
        • be careful that ldrainage pathways are open
          • regular bowel movements, sweating, sufficient fluids
        • want to detox from a position of strength

what the listenercan do

  • breathing exercise
  • try a low histamine diet for a week or two to see if there is any difference. (not recommended for long term)
  • high histamine foods listed in guide Go.megmlll.com /histamine
    • Banana, avocados, tomatoes, strawberries, aged cheeses, fermented foods, cured meats, alcohol, cheese,
    • Watch freshness keeping a couple of days can have histamine grow
      • Cooked meats will grow histamine faster
      • Want to flash freeze cooked meals.
  • Prepare for detox
    • Insure are having regular bowel movements, sweating, lymph drainage
      • Dry brushing, rebounding for lymph movment
      • Need to make shure that whatever is moved, gets out of the body.
    • Have to be in good shape as body has to be prepared for the toxins being pushed out of body

Tests

  • GI map, stool test, organic acid, hormone testing, mycotoxin testing, tick borne illness testing
  • There is not a clear test for histamines
    • So first try a histamine diet to see if feeling better.