Hayfever, Histamine & Functional Nutrition: A Closer Look at What’s Really Going On
- Laila Charlesworth
- Jun 24
- 3 min read
As summer settles in across Yorkshire, so does hayfever — known clinically as seasonal allergic rhinitis. For many, this means itchy eyes, nasal congestion, sneezing fits, and fatigue. But behind the pollen charts and antihistamines lies a fascinating biochemical story — one that nutrition is uniquely positioned to support.
Histamine: The Double-Edged Sword
Histamine is often labelled the “villain” in allergy season, but the reality is more nuanced. It’s a bioactive amine (a naturally occurring compound derived from amino acids that acts on the body — often as a signalling molecule), with essential physiological roles:
Immune signalling: histamine is released from mast cells in response to perceived threats (like pollen).
Vasodilation: it increases blood flow and capillary permeability, helping immune cells reach affected tissues.
Gastric acid secretion, neurotransmission, and wound healing are also histamine-regulated.
The problem during allergy season isn’t histamine itself — it’s the excess of it, or your body’s reduced ability to degrade it efficiently.
Degradation Matters: Why You React and Others Don’t
Two key enzymes are responsible for breaking down histamine:
Diamine oxidase (DAO): active in the gut and bloodstream
Histamine-N-methyltransferase (HNMT): active intracellularly, especially in the central nervous system
When histamine production (from pollen exposure, stress, or histamine-rich foods) outpaces these enzymes’ capacity, symptoms intensify. This is one reason why someone with optimal DAO function may breeze through June, while another is struggling to leave the house.
Histamine Load: It's More Than Just the Air
What many people don’t realise is that histamine levels are influenced by diet, gut health, and nutrient status. Certain foods (like fermented items, aged cheeses, and alcohol) are naturally high in histamine. Others may trigger endogenous histamine release - citrus, shellfish, or even tomatoes in some individuals.
What’s more, the gut lining plays a major role: damaged intestinal barriers (e.g. imbalanced gut microbiome, low-grade inflammation, or small intestinal bacterial overgrowth) can both increase histamine production and impair its clearance.
Nutrition: Targeting the Root, Not Just the Symptoms
As a nutritionist, my role is to identify and address the underlying contributors to histamine overload — not simply suppress the response.
Some areas I explore with clients include:
Micronutrient status: cofactors like vitamin C, B6, copper, and magnesium are essential for DAO activity.
Flavonoids and polyphenols: compounds like quercetin may help stabilise mast cells and modulate histamine release.
Gut restoration: supporting microbial balance and mucosal integrity can reduce systemic histamine burden.
Food mapping: identifying and minimising high-histamine foods strategically, not restrictively.
Rather than reaching for higher doses of antihistamines, we explore how to lower the overall histamine threshold, supporting tolerance naturally and sustainably.
Practical Starting Points
If you're experiencing hayfever, try these science-backed interventions:
Use a HEPA filter indoors and keep windows closed during peak pollen hours.
Shower and change clothes after outdoor exposure to limit pollen carry-over.
Prioritise hydration to support histamine clearance through urine.
Reduce alcohol and fermented foods temporarily if symptoms are flaring.
Hayfever doesn’t have to be a rite of passage each summer. If you suspect your reactions go beyond pollen, or if you’ve “tried everything” — a functional lens can offer new insight.
Interested in a personalised approach to histamine support? I work with clients to investigate root causes and build a targeted plan that supports balance — not just symptom suppression.
Get in touch to explore whether functional nutrition could help this hayfever season.
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