Hi Friend

Today I want to talk about something that’s becoming more common than anyone realises:
Mast Cell Activation Syndrome (MCAS).

I will be doing a live webinar on this topic today, i do a weekly webinar inside my community:

Join Here for full access

If you’ve ever experienced:

…then you may have been living in the MCAS loop without even knowing it.

But here’s the real secret:
MCAS doesn’t just affect your immune system.

It affects your nervous system, your gut microbiome, and even your microglia — the brain’s immune cells that control pain, inflammation, mood, and fatigue.

Let me explain.

Mast cells are immune cells that sit in places like your:

They act like bodyguards.
Their job is to detect danger and release chemicals (like histamine) to protect you.

But in MCAS, something changes.

These mast cells become trigger-happy — releasing chemicals even when there’s no real threat.

Suddenly your body thinks:

🌡️ “This food is dangerous.”
🌬️ “This smell is dangerous.”
💬 “This stress is dangerous.”

This is why so many symptoms feel random, unpredictable, or unrelated.

They’re not unrelated.
They’re connected through mast cell signalling.

Your mast cells and your nerves talk to each other constantly.

When mast cells activate, they stimulate the vagus nerve, pain fibres, and the sympathetic system.

This can cause:

But here’s the interesting part:
Your nervous system can activate your mast cells, too.

Meaning:

Stress → activates mast cells
Mast cells → activate nerves
Nerves → activate mast cells again

A closed loop.

This explains why MCAS flares so often happen during:

Your body isn’t weak.
It’s overprotected.

The gut is packed with mast cells — and when they become reactive, they can:

But it goes deeper:

Certain histamine-producing bacteria flourish when mast cells are inflamed.

This changes your tolerance to foods dramatically.

Norepinephrine + cortisol (from stress) can shift bacterial populations within HOURS.

Dysbiosis → endotoxins → mast cell activation → more inflammation.

Another closed loop.

This is why MCAS is rarely just an allergy issue.
It’s a gut–brain–immune loop.

MCAS does not mean your body is broken.

It means your body is overreacting because it learned to survive.

And that loop can be calmed from multiple directions:

Breathwork, vagal toning, grounding, somatic work.

These reduce mast cell firing.

Low-histamine rotation, gentle probiotics, gut lining repair, fibre variety.

This reduces inflammatory triggers.

Mast cells respond directly to emotional memory and stress signals.

When you calm your survival system, mast cells calm too.

Sound therapy, meditation, anti-inflammatory routines.

Microglia + mast cells work closely together — you calm one, you influence the other.

Crashes → mast cell activation
Stability → mast cell calming

It’s all connected.

MCAS is not rare.
It’s not “allergies.”
And it’s not “in your head.”

It’s a whole-body pattern of overprotection, shaped by:

And the most hopeful part?

Your body can unlearn this pattern.

With the right tools, you can break the loop and build predictable energy, calmer digestion, fewer reactions, and a more stable baseline.

This is exactly what we work on inside the Mend Collective — safely, gently, and step by step.

More info here

Tomorrow we will discuss how to diagnose mcas!

Stay Well

Dr Ahmed