Every spring, I see a steady stream of patients struggling through the same familiar symptoms: itchy eyes, sneezing, congestion, and fatigue.
Plus a whole bundle of side effects, like drowsiness from the medication.
Hayfever, or seasonal allergic rhinitis if you are feeling technical, is often dismissed as a minor inconvenience, yet for many patients it represents a significant inflammatory burden that impacts sleep, cognition, and overall quality of life.
It might also be a warning sign that they might not respond to care as expected, which is why we have it on our health questionnaire – if you have a SUSTAINED INFLAMMATORY RESPONSEyou are going to have peripheral and central hypersensitivity, creating a lower pain threshold, which means persistent pain and persistent muscular guarding.
Conventional approaches tend to focus on blocking histamine at the receptor level using antihistamines.
While this can provide short term relief, it does little to address the underlying drivers of histamine overload/intolerance.
A more effective clinical strategy is to reduce the total histamine burden itself.
This is where a functional, two step approach becomes powerful.
Quick recap on where histamine comes from:
- You eat histamine in aged foods (cheese, wine, cured/cooked meats, fermented foods, fish).
- We make histamine from histadine (an amino acid).
- Our gut microbiome can also make histamine.
Histamine removal:
Outside the cell (gut lumen mainly and kidney, interstitial spaces), histamine is broken down by DAO.
Inside the cell, histamine is broken down via a process known as methylation. In this case, the enzyme specifically is HNMT.
Remember, methylation requires methyl B12, Methylfolate and B6 primarily.
Step 1: Reduce Histamine Load at the Gut Level (DAO Support)
The body relies heavily on DAO, to break down histamine in the gut before it enters circulation.
When DAO activity is insufficient, histamine accumulates more easily, priming the immune system and amplifying responses to environmental triggers such as pollen.
There are several reasons why DAO activity may be compromised:
- Gut inflammation damaging the intestinal lining
- Nutrient insufficiencies such as copper and vitamin B6/C
- Genetic variability (DAO gene snp’s)
- High histamine diets
- Alcohol intake
In this context, supporting DAO becomes a logical first line intervention. By breaking down histamine before it is absorbed, you effectively reduce the total load entering the system.
Clinically, this often leads to:
- Reduced severity of acute symptoms
- Less reactivity to pollen exposure
- Improved tolerance to histamine rich foods
This is not about blocking histamine.
It is about removing it upstream, which is a far more elegant and physiological strategy.
We love NaturoDAO as it is vegan and half the price of DAO from pig kidney.
How powerful is DAO in patients with histamine intolerance?
The results are amazing: After 4 weeks on DAO, a 66% reduction in overall symptoms.
Step 2: Clear Histamine Inside the Cell (Methylation Support)
Even with optimal DAO activity, histamine is still produced endogenously and released during immune responses.
Once histamine is inside the body and within cells, it is primarily broken down via methylation.
This process relies on histamine N-methyltransferase, which requires adequate methyl donor availability.
This is where many patients fall short.
Suboptimal methylation capacity can result from:
- Low folate intake or poor conversion to active forms from folic acid
- Low vitamin B12
- High stress increasing methyl demand
- Genetic polymorphisms affecting methylation enzymes
When methylation is insufficient, histamine clearance slows, leading to a prolonged inflammatory signal.
This is where targeted support becomes clinically valuable.
Using a well-formulated methylation complex, such as a METHYL B HERO, helps provide the cofactors needed to drive intracellular histamine breakdown.
From a practical standpoint, supporting methylation can:
- Shorten the duration of histamine responses
- Reduce systemic inflammation
- Improve energy and neurological symptoms often associated with hay fever
The key point is this:
DAO reduces what gets in. Methylation clears what remains.
Not sure what METHYLATION is? Check out this short video
The Missing Piece: Reducing Immune Activation
While managing histamine directly is essential, it is equally important to reduce the upstream drivers of immune activation.
Two of the most common dietary contributors are gluten and dairy.
In susceptible individuals, these foods can:
- Increase gut permeability
- Stimulate immune activation
- Drive low grade inflammation
- Increase histamine release indirectly
When the immune system is already activated, exposure to pollen becomes the tipping point rather than the sole cause.
Removing gluten and dairy, even temporarily during peak hay fever season, can:
- Reduce overall immune load
- Lower histamine release
- Improve gut integrity
- Enhance response to DAO and methylation support
Clinically, this often produces a noticeable reduction in symptom severity when combined with the two-step approach.
Bringing It Together in Practice
A simple and effective framework for patients:
1. Lower incoming histamine
- Support DAO activity
- Reduce high histamine foods if needed
2. Improve internal clearance
- Support methylation with active B vitamins
- Ensure adequate B12, folate, and B6 status
3. Reduce immune triggers
- Trial removal of gluten and dairy
- Support gut health where appropriate (butyrate is IDEAL as it heals and seals the gut and is also a MAST CELL stabilsier).
Hay fever is not just about pollen. It is about the body’s total histamine burden and its ability to manage it.
By shifting focus from blocking symptoms to improving histamine handling/overall load, clinicians can offer patients a far more robust and sustainable solution and help adjustments work better.
This approach aligns with a core principle in nutrition and Chiropractic:
The goal is not to suppress the response, but to improve the system’s capacity to regulate itself.
When DAO is supported, methylation is optimised, and immune triggers are reduced, patients are no longer simply coping with hay fever. They are becoming more resilient to it.
NOTE: If the patient normally struggles with hay fever (or other symptoms), but becomes pregnant and experiences a massive reduction or complete absence of symptoms, it almost always means their DAO production is compromised in the gut and they have histamien intolerance.
During pregnancy, DAO increases massively increases in order to stop premature delivery and is a key signal to look at histamine post partum.
Re-read that here:
