If you've been told you have histamine intolerance or Mast Cell Activation Syndrome (MCAS), chances are you've also been given a long list of foods to avoid.
Tomatoes. Bananas. Avocados. Spinach. Strawberries. Citrus. Leftovers. Fermented foods.
Maybe removing some of them helped.
But here's the question I don't think we ask often enough:
Why did your body suddenly start reacting in the first place?
Especially when many of these were foods you ate without a problem for years.
Histamine isn't actually the enemy
Histamine is something your body naturally makes—and needs.
It's an important signaling molecule involved in immune responses, digestion, circulation, the nervous system and even our sleep-wake cycle.
Mast cells are immune cells that can release histamine when they're activated.
But here's the part that often gets lost:
Histamine is part of the response. It doesn't necessarily tell us what started the response.
Think about a smoke alarm.
When the alarm sounds, we certainly want to quiet it.
But we also want to know:
What's creating the smoke?
This is where “histamine intolerance” can become confusing
People experiencing flushing, itching, headaches, heart racing, digestive symptoms, congestion, fatigue, brain fog or reactions after eating may be told that histamine is the problem.
And sometimes reducing high-histamine foods or using antihistamines brings genuine relief.
That matters.
But improvement doesn't necessarily prove that histamine was the root cause of the problem.
It tells us that histamine may be participating in the symptoms.
Even conventional medicine recognizes that this is complicated. There is no single definitive test that can explain every suspected case of histamine intolerance, and experts continue to debate how broadly MCAS should be diagnosed.
So perhaps we need to be careful about turning a complex pattern of symptoms into one simple explanation.
Mast cells aren't just about allergies
This is where the biology becomes really interesting.
Mast cells are part of our immune defense system. They don't only respond to pollen or a food allergen.
They communicate with other immune cells and the nervous system. They participate in responses to infections and tissue injury. And when activated, they release much more than histamine.
So when mast cells are repeatedly activated, I want to know:
What are they responding to?
That's a very different question from simply asking:
Which foods contain histamine?
Why does food get blamed?
This is one of the areas I've become increasingly curious about.
Someone eats a food.
They experience symptoms.
They look the food up and discover that it appears on a “high-histamine” or “histamine-liberating” list.
The food gets removed.
Then another food causes symptoms.
That food gets removed too.
And slowly, the list of safe foods becomes smaller and smaller.
There are certainly times when avoiding a food is necessary, particularly with a true allergy or a significant reproducible reaction.
But: A reaction after eating a food doesn't automatically tell us why the reaction occurred.
That's an important distinction.
What if we're looking too far downstream?
My approach to complex chronic illness has been shaped by conventional medicine, functional and holistic medicine, years of working with highly sensitive patients, and the Medical Medium information developed by Anthony William.
One of the concepts from the Medical Medium work that has particularly changed the way I think about histamine is the idea that the food may not always be the underlying problem.
William connects chronic histamine reactions with viral/pathogen activity, accumulated toxic burden and an overburdened liver.
He describes a state he calls “Dirty Blood Syndrome,” in which the liver is struggling to adequately manage the accumulation of toxins, pathogen waste and other unwanted substances circulating through the bloodstream.
This is not a conventional medical diagnosis, and this proposed mechanism has not been established as the scientific explanation for MCAS or histamine intolerance.
But it raises a question I believe is worth asking:
What if some of these reactions are telling us more about the internal environment of the body than about the food itself?
Interestingly, science already recognizes individual pieces of a much larger picture.
We know mast cells participate in responses to pathogens.
We know the nervous system and mast cells communicate.
We know the gut and immune system interact.
We know the liver participates in histamine metabolism.
And we know environmental exposures can influence immune function.
We don't yet fully understand how all of these factors come together in the person who suddenly seems to react to everything.
There may be another reason food reactions become confusing
In the Medical Medium framework, foods can be associated with histamine reactions for very different reasons.
William teaches that certain foods can support pathogens, contributing to greater problems.
But he also teaches that healing and cleansing foods can sometimes temporarily increase symptoms as the body begins dealing with accumulated toxins and pathogen debris.
That's a radically different interpretation of:
“I ate this food and felt worse.”
It means the observation is important—but our interpretation of that observation matters too.
A reaction doesn't automatically mean:
“This food is bad for me.”
It may mean we need to ask:
What is happening inside my body that is making me react?
What changed?
This may be one of the most useful questions you can ask yourself.
Were you always this sensitive?
Or did something happen before the reactions began?
A significant illness?
COVID or another viral infection?
A medication or surgery?
Chemical or environmental exposure?
A prolonged period of tremendous stress?
Chronic pain?
A major hormonal transition?
Digestive problems?
Or did the sensitivities gradually accumulate over many years?
You may not immediately know the answer.
That's okay.
The purpose isn't to find something to blame.
It's to start looking upstream.
Maybe the goal isn't simply to lower histamine
If avoiding certain foods gives you relief, that's meaningful.
If medication helps control significant symptoms, that's meaningful too.
This isn't about taking away something that is helping you.
It's about recognizing the difference between managing the reaction and understanding what may be driving it.
Because if your list of tolerated foods keeps shrinking...
If you're reacting to supplements, smells, medications and foods...
If you've followed a low-histamine diet but still don't feel well...
Then perhaps it's time to ask a different question:
What if we need to change the terrain?
Instead of spending all of our energy chasing individual histamine triggers, what if we also began working on the internal environment in which those reactions are occurring?
What if we looked at pathogen burden?
Toxic exposures?
Liver health?
Dietary fat?
The nervous system?
Chronic pain and stress?
Nutrition?
The gut?
And most importantly, the individual history that brought this particular person to this point?
Because two people carrying the same MCAS or histamine-intolerance label may have arrived there through very different paths.
And that means their path forward may need to be different too.
Histamine may be the messenger—not the root problem.
Instead of spending a lifetime trying to silence the messenger, perhaps we should also be asking:
Why is the message being sent?
And once we begin asking that question, the next one becomes:
How do we change the terrain?
That's where we'll go in Part 2.
