Fighting Histamine

24 April 2019

Histamine is made by the body and stored in cells called mast cells as well as found in certain foods. Histamine intolerance is the result of an excess accumulation of histamine against the capacity for histamine degradation. Basically, a threshold is reached and when exceeded symptoms that resemble allergies occur including runny nose, itchy eyes, sneezing, hives, asthma, and chronic cough, as well as other symptoms including headaches, joint pain, anxiety and insomnia.

Histamine is degraded (metabolised) by two predominant enzymes:

  1. The enzyme DAO: Diamine oxidase (formerly known as histaminase) is responsible for the breakdown of extracellular histamine and dietary histamine.
  2. The enzyme HNMT (histamine-N-methyl transferase) inactivates histamine only intracellularly

Exceeding a histamine tolerance threshold results in a variety of symptoms. This is because there are four histamine receptors in the body (H1R, H2R, H3R and H4R - not very excitingly named!) and these receptors are tissue and organ-specific, therefore triggering a diverse range of actions and symptoms. Stimulation of histamine receptors may cause: smooth muscle cell contraction, vasodilation, increased vascular permeability and mucus secretion, tachycardia, blood pressure changes, increased gastric acid secretion, and stimulation of nociceptive nerve fibres. These actions may result in a variety of symptoms including headache, gastrointestinal disturbance, eczema, respiratory symptoms and in women, dysmenorrhoea - as shown here:


Various possible mechanisms cause of histamine intolerance:

  • As the enzyme Diamine oxidase (DAO) is produced in your kidneys, thymus, and predominately the intestinal lining of your digestive tract, any damage to the enterocytes in gastrointestinal disease or SIBO may cause a significant reduction in DAO and thus an imbalance between production / ingestion vs degrading capacity.
  • Similarly, low levels of B6 (pyridoxal-5 phosphate ) or S-adenosyl methionine reserves which are needed by HNMT enzymes may cause an imbalance between production / ingestion vs degrading capacity
  • Adding to this, increased histamine concentrations may result from endogenous (originating from within the body) histamine overproduction from allergies, bacteria, or bleeding.
  • Ingestion of histamine-rich foods, alcohol and some drugs can also exceed one's threshold.
  • Histamine is classified as an amine - others including tyramine may also cause intolerances possibly through competitive inhibition of DAO. Some foods including citrus can also liberate the release of histamine from mast cells.
  • Some medications have shown antagonistic action towards DAO, while others stimulate histamine release. Therefore, the intake of drugs, especially long-term medication, may be another cause of acquired Histamine Intolerance - see table following:

  • Finally, we must consider what can trigger mast cells to degranulate.

Environmental triggers of mast cell degranulation:

Mast cells are an essential player in our innate immune system - patrolling the front lines of our connective tissue, skin, intestinal lining cardiovascular system, nervous system, and reproductive organs. When the body is exposed to a perceived threat (this can be environmental toxins, mould, chemicals, gut infections like SIBO or pollen) the mast cells explode or degranulate and release histamine and other chemical mediators such interleukins, prostaglandins, cytokines, and chemokines. These chemicals in turn result in promoting inflammation and swelling, contraction of smooth muscle (which results in symptoms such as stomach cramps and heart palpitations), stimulate gastric acid production (maybe causing reflux) and increase mucous production (congestion, sneezing, etc).  

So, while we generally think of histamine and mast cells in relation to an allergic response such as hayfever, we now know mast cell activation and the release of all these chemicals and mediators they play a key role in many other disorders, such as CIRS (Chronic Inflammatory Response Syndrome), Chronic Fatigue Syndrome, Eosinophilic Oesophagitis, POTS (Postural Orthostatic Tachycardia Syndrome), Fibromyalgia Interstitial cystitis, endometriosis and GERD.

The trigger/s dock and attach to receptors – called toll-like rectors (see image below) on the mast cell membrane, activating a reaction that causes the release of histamine and chemical mediators.

Or another mechanism is termed cross-linking of an IgE antibody on the cell surface following the binding of the allergen:


Managing histamine intolerance and Mast Cell Activation

1. Lowering the overall histamine load through diet is a great start, by decreasing consumption of high histamine foods (I provide clients with a more detailed food plan):

  • Avoid raw and cured sausage products such as salami.
  • Avoid processed or smoked fish products & seafood.
  • Avoid pickles and ferments
  • Avoid citrus fruits.
  • Avoid chocolate
  • Avoid walnuts, pecans and sesame
  • Avoid products made with yeast and yeast extracts
  • Avoid soy sauce and fermented soy products
  • Avoid tea and instant coffee
  • Avoid aged cheese
  • Avoid spinach in large quantities
  • Avoid tomatoes, ketchup and tomato sauces
  • Avoid aubergines
  • Avoid beer, wine and champagne beverages
  • Avoid artificial food colourings & preservatives
  • Avoid certain spices: cinnamon, chilli powder, cloves, anise, nutmeg, curry powder, cayenne pepper

2.     Stabilise mast cells to inhibit degranulation

Omega 3 fatty acids can stabilise mast cells

I like Lion Heart Pure Omega 3 Fish Oil - 150ml

In 2012, a research group from Tufts University conducted a series of in vitro experiments to explore differences in the effectiveness of quercetin and cromolyn for mast cell stabilisation. Using cultured human mast cells, they found that quercetin was more effective than cromolyn for inhibiting the release of IL-8 and TNF—two cytokines that are both released by mast cells as part of the immune response.  I like Biocare’s Quercetin Plus.

3.    Try DAO Supplements:

Histamine Block by Seeking Health contains a patented enzyme formula providing 20,000 HDU of diamine oxidase (DAO).

And this product - which I am trying to get in: NeuroProtek® is a unique all natural oral dietary supplement in a soft gel capsule, which may reduce symptoms of gut and brain inflammation and nerve damage. NeuroProtek® uses an exclusive combination of flavonoids, based on the scientific research of Dr. Theoharides M.D., PhD, which have shown to reduce oxidative stress and inflammation both in the gut and the brain.

4.    Finally, work with a practitioner that can help uncover triggers and root causes.

In health, Tanya x