Could Histamine Be the Hidden Cause of Your Symptoms?

What Is Histamine?

When you hear the word histamine, you probably think of hay fever, allergies or maybe even antihistamines, those little tablets you reach for during spring. But histamine is much more than just a seasonal troublemaker, It’s actually a vital chemical messenger involved in many body systems.

Histamine helps your body:

• Fight infections by triggering inflammation (a normal part of the immune response)

• Regulate stomach acid for proper digestion

• Act as a neurotransmitter, influencing wakefulness, appetite and mood

• Modulate hormone levels, particularly oestrogen

• Support wound healing and blood vessel dilation

  
  

How Does Too Much Histamine Affect the Body?

Under normal circumstances, histamine is released and then quickly broken down by two main enzymes: DAO (diamine oxidase) and HNMT (histamine N-methyltransferase). Sometimes your immune system can become overwhelmed leading to histamine can build up and symptoms that mimic allergic reactions, with no obvious allergen. This is known as histamine intolerance.

Mast cells which store and release histamine may also become overactive and start releasing excess histamine unnecessarily. This triggers systemic inflammation and a wide range of symptoms such as itching, flushing, headaches, nausea, brain fog, digestive issues, changes in blood pressure and even mood changes. This condition is known as Mast Cell Activation Syndrome (MCAS).

Histamine intolerance and MCAS are now increasingly recognised as underlying causes of many unexplained chronic symptoms from mood swings, anxiety and PMDD to migraines, hormone imbalances and digestive disorders. These conditions can appear seemingly “out of nowhere” and are often triggered by gut microbiome shifts, stress, or an illness like a viral infection.

What Is the Methylation Cycle?

The methylation cycle is a key biochemical process that occurs in every cell of your body, millions of times per second. It’s like a metabolic engine that transfers a small molecule called a methyl group to other compounds in order to activate or deactivate them.

Methylation plays a vital role in:

• Detoxification (especially in the liver)

• Neurotransmitter production and breakdown (e.g. serotonin, dopamine and noradrenaline)

• DNA synthesis and repair

• Hormone metabolism

• Gene expression regulation

• Immune function and balance

How Methylation Affects Histamine

Histamine is broken down through two main pathways:

• DAO: works primarily in the gut to break down histamine from food and bacteria

• HNMT: works in the liver, kidneys and brain, and depends on a well-functioning methylation cycle to do its job

When methylation is sluggish, the HNMT enzyme can’t work efficiently. As a result, histamine builds up in the body, particularly in sensitive tissues like the brain and nervous system.

What Can Impact Methylation?

Several factors can impair the methylation cycle, including:

• Genetic variants 

• Low levels of specific nutrients 

• Chronic stress, which depletes nutrients required to support methylation

• Toxin exposure (e.g. heavy metals, mould or chemicals)

• Gut dysbiosis, which interferes with nutrient absorption and increases histamine load

The Vicious Cycle: Histamine and Hormones

Poor methylation doesn’t just affect histamine. It also impacts oestrogen metabolism. In turn, oestrogen stimulates mast cells to release more histamine and histamine increases oestrogen, creating a feedback loop that worsens symptoms.

When methylation is compromised:

• Histamine is not broken down effectively

• Oestrogen isn’t cleared efficiently

• Inflammation increases

• Mood and neurological symptoms intensify

This is why people with methylation issues, even mild ones often experience flare-ups of histamine intolerance, anxiety and hormonal symptoms, especially during times of stress, gut imbalance or hormonal shifts like ovulation or perimenopause.

So, How Do We Fix It?

If histamine overload, poor methylation or mast cell issues are driving your symptoms, the goal isn’t just to suppress them, it’s to support your body’s natural balance, particularly in the gut, nervous system and detox pathways.

Here's where to start:

1. Identify and Support Your Methylation Pathways

Find out if your methylation is impaired (including your genetic variants), then use targeted nutrients and foods that support methylation.

2. Reduce Your Histamine Load

Avoid high histamine foods and potential environmental or other food triggers.

3. Support the Gut and Microbiome

Address dysbiosis and support intestinal barrier function including identifying and eliminating any potential infections.

4. Stabilise Mast Cells and Reduce Reactivity

Support mast cell function drawing upon stabilisers and focusing on lifestyle support to aid the nervous system, immune system and adrenal system to function optimally.

5. Balance Hormones and Reduce Inflammation

Support hormone clearance through detoxification pathways and support regulation of inflammatory processes to ensure optimal cellular health.

Histamine intolerance and methylation imbalances are often overlooked causes of chronic, confusing symptoms however when you understand the interconnected roles of gut health, hormones, stress and nutrient pathways, you can begin to support the body instead of fighting it.

If you suspect histamine is affecting your health, book a session to assess your underlying drivers and create a personalised plan to restore balance.

Book now