HISTAMINE

Histamine, Histamine Intolerance and Mast Cell Activation Syndrome

What is Histamine?

Histamine [2-(4-imidazolyl)-ethylamine] is an amine produced by various cells including mast cells, basophils, histaminergic neurons, platelets, and gastric enterochromaffin cells. Histamine is best described as a cell signalling molecule as it’s main activity is relaying information between cells in the body via four types of receptors namely H1, H2, H3, and H4 (the “H” stands for Histamine). Histamine binds to a receptor on a cell and basically says “do it” the type of receptor will determine what the job is for the cell to “do”.

In some cases histamine is acting as an inflammatory mediator causing swelling and triggering other immune cells to respond to a site of damage, toxin or infection.

Take the example of a bee sting, your immune system will respond to the venom (a toxin) by triggering mast cells to release histamine, histamine triggers the release of other immune cells while also dilating capillaries, causing swelling.

This swelling creates space enabling the immune cells to rapidly respond to the venom and neutralise it.

Histamine has many other functions in the body beyond the production of an immune response.

Histamine acts as a neurotransmitter in the brain, it regulates of physiological functions in the gut, stimulating acid secretions and motility and it is involved in the sleep-wake cycle.

Sometimes a histamine response becomes a problem of itself as in an acute allergic reaction that causes swelling in the mouth, throat and airways known as anaphylaxis and can be life threatening or hay fever that goes on for days or weeks and becomes a real nuisance.

The body is usually well-equipped to prevent the build-up of excess histamine; normally after delivering it’s message histamine is quickly broken down by an enzyme called Histamine Methyl Transferase (HNMT). Histamine is also found in various amounts in foods containing the amino acid histidine. Fermentation, curing, and slow cooking, convert histidine to histamine thereby increasing the food’s histamine content. This dietary form of histamine can be broken down in the gut by another enzyme called Diamine Oxidase.

In some cases, the body may be unable to adequately deal with the histamine produced or consumed and histamine will accumulate in the body, this can lead to chronic non-resolving inflammation and is responsible for many disturbing symptoms and chronic ill health.

There are three main ways that histamine can reach excessive amounts and adversely affect your health.

1. Mastocytosis

This is a rare genetic condition caused by an excess of altered mast cells. The increase in mast cell numbers results in very high levels of histamine being produced.

2. Histamine Intolerance or Food-induced Histaminosis

Histamine intolerance is not a true food intolerance but comes from the body’s inability to process or eliminate the ingested histamine within an average timeframe. Some foods are naturally higher in histadine or histamine and if these are avoided or minimised symptoms can be reduced.

3. Mast Cell Activation Syndrome (MCAS)

MCAS is different from an intolerance caused by histamine consumption: it refers to a condition where the mast cells become hyper stimulated and unstable releasing increased amounts of histamine in response to immune activation.

This exaggerated reaction can then lead to the repeated release of an excess of histamine (as well as other chemical mediators like cytokines, prostaglandins, and interleukins), causing various symptoms as shown below.

Common symptoms of MCAS

Since mast cells and their receptors are found throughout the body, MCAS can affect any organ system. For instance, MCAS can cause distress in the:

Central and peripheral nervous systems producing headaches and migraines, irritability, anxiety and/ or depression, sleep disturbances, circadian rhythm imbalance, “Brain fog”, vertigo, low blood pressure, numbness, pins and needles, tics, reduced motor control and cognitive dysfunction.

Reproductive system where it is involved in oestrogen metabolism and can cause PMS, period pain, pelvic pain, endometriosis, fibroids or adenomyosis.

Respiratory system we are all familiar with hay fever, itchy watery eyes, wheezing or shortness of breath, nasal congestion or drip.

Digestive system including difficulty swallowing, abdominal pain, nausea, bloating, cramping, diarrhoea, constipation, and can lead onto inflammatory bowel disease, trigger and perpetuate leaky gut leading to food and chemical sensitives.

Cardiovascular system with symptoms of chest pain, palpitations, hypertension, tachycardia or bradycardia and dysrhythmia.

Integumentary system (skin) causing hives, rashes, dermatographism, heat, flushing, swelling, pain, tenderness and itching.

As you can see, histamine intolerance and MCAS cause many symptoms depending on which body systems are affected. Some people may only see symptoms expressed in one area such as the respiratory tract with hay fever and asthma while others will express symptoms across several body systems.

Conditions associated with MCAS

In addition to the symptoms listed earlier, the following conditions are associated with MCAS:

Autism, Allergies and Asthma, Food Allergy and Intolerance, Eosinophilic Esophagitis, Chronic Fatigue Syndrome, Fibromyalgia, Multiple Chemical Sensitivity, CIRS (Chronic Inflammatory Response Syndrome), POTS (Postural Orthostatic Tachycardia Syndrome), Autoimmune disorders (Hashimoto’s thyroiditis, lupus, etc.), Coeliac Disease, Irritable Bowel Syndrome, GORD Gastro-oesophageal Reflux Disease), Interstitial Cystitis, Migraines, Mood disorders (Anxiety & Depression) and Insomnia.

What can trigger MCAS?

Most people will realise they were not born this way but have acquired the problem at some point in their life.

Mast cells can become overactive due to stress or trauma, gut dysbiosis or infections caused by bacteria, viruses or fungi but most commonly the cause will be due to environmental toxins, medications and foods that damage the gut wall leading to leaky gut or increased intestinal permeability. Food particles and other fragments can easily get into the blood when the gut barrier is compromised leading to immune activation, the production of anti-bodies and subsequent stimulation of mast cells. Eighty percent of immune cells are resident in the human gut and seventy percent of histamine is made there. If this excessive amount of histamine is not broken down it can travel to other sites of the body and cause symptoms in any body system as described above.

Nutrient deficiencies – Sufficient vitamin B6, Zinc, Selenium and Copper are required for DAO production and function. Nutrient deficiencies can be caused by suboptimal digestive function, higher nutrient demands (such as in cases of stress, anxiety, or poor sleep quality), and a nutrient-poor diet. Methyl groups donated from methyl folate are required for manufacture of Histamine Methyl Transferase (HNMT); a gene mutation on MTHFr genes can significantly reduce production of methyl groups and subsequently reduce production of HNMT.

What can you do to correct or alleviate MCAS?

If you have done any reading on this topic you will see long lists of foods (high in histamine) to avoid and long lists of vitamins, herbs and other supplements to take to reduce mast cell activity or block histamine receptors, however there is an easier way.

Bio-Compatibility Testing

If you have tried allergy or intolerance testing and have followed strict histamine elimination diets in the past but are still having symptoms our Bio-Compatibility Test offers you something new. Our test is different in that we use a hair sample and we are looking for foods that may be causing or aggravating symptoms and ultimately preventing your body from healing. Obviously because this test uses a hair sample it is not an antibody test however with over 34 years of testing and research our observations confirm that patients can expect up to 60% improvement to histamine related symptoms within four weeks of eliminating incompatible foods.

I use this dietary information as a basis for treatment and use vitamins, herbs and supplements to assist with correcting the underlying cause of MCAS; remember most people were not born this way.

Restoration of gut permeability is essential as is upregulating detoxification pathways and restoring immune balance.

The other side of MCAS is the inefficient breakdown of mast cell mediated and dietary derived histamine. Nutrients that support the production and utilisation of Histamine Methyltransferase and Diamine Oxidase must also be considered, these include vitamins B1, B2, B12, B6, B9 (folate) zinc, selenium and copper).

Consumption of histamine-rich foods, foods that trigger histamine release from mast cells or foods that naturally block DAO can trigger, or worsen, symptoms in individuals suffering from histamine intolerance or MCAS. I encourage patients to minimise or avoid histamine rich foods for four weeks which can help to reduce the histamine burden on the body in the initial phase of treatment however trying to avoid these foods as your only treatment plan will make your diet too restrictive, difficult to maintain in the long run and will only give you minimal results.

This type of restrictive diet is most beneficial for people with histamine intolerance and will be of little benefit to those with MCAS.

For more information about our Bio-Compatibility test click here.