Histamine intolerance explained simply

Jannyn Saß 01/05/2024

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Fig. 1: Abdominal pain is one of the possible symptoms of histamine intolerance.

Symptoms often appear after eating: red patches and tingling of the skin, a racing heart or abdominal pain. Or perhaps the nose has been running for some time, there are breathing difficulties or the skin itches.

This can be caused by histamine intolerance, which often presents with diffuse symptoms. Symptoms can be mild, but for some people they can make life very difficult. In Germany alone, more than two million people suffer from histamine intolerance. [1] Women are particularly affected: up to 80% of histamine intolerance patients are female. [2]

Read here how histamine intolerance (HIT) manifests itself and what you can do about it.

Histamine intolerance: what lies behind it?

Histamine is a tissue hormone found almost everywhere in the human body. It is present in the skin tissue, the lungs, the stomach, the intestines and also in the brain. [3] Histamine is involved in various immune functions and also acts as a neurotransmitter. [4] Among other things, histamine is important for:

dilation of peripheral blood vessels (vessels in the arms and legs),
constriction of central blood vessels (vessels supplying the heart and brain),
narrowing of the airways,
contraction of the uterine muscle,
contraction of the intestinal muscles, and
regulation of important processes in the brain such as hormone release and sleep–wake rhythms.

One role of histamine is to trigger inflammation. This is important and a completely natural process of the immune response, because it is only in this way that white blood cells can find and attack pathogens or harmful substances in the body. However, when this process gets out of balance, it is referred to as histamine intolerance. In that case, histamine builds up in the body and is not broken down adequately as it would be normally. This can lead to a variety of symptoms on both a physical and psychological level. [5]

How histamine intolerance manifests

The symptoms resemble an allergy in many respects. However, histamine intolerance is not an allergy, as is often assumed. It is a metabolic disorder in which the breakdown of histamine in the body is impaired.

By contrast, in a seasonal allergy symptoms always develop as a result of an increased release of histamine.

The physical symptoms of histamine intolerance are varied

Complaints in histamine intolerance vary from person to person. They can affect the whole body or only produce isolated symptoms. The most common symptoms of histamine intolerance include:

Gastrointestinal tract:
- digestive problems such as diarrhoea, nausea, vomiting, stomach cramps, intestinal cramps, constipation, acid reflux
Allergic symptoms:
- stuffy or runny nose
- asthma
Skin problems:
- eczema, itching, hives, urticaria, swelling, psoriasis and other skin issues, skin redness, strong reactions to insect bites, acne, skin blemishes, rash, tingling skin
Autonomic nervous system symptoms:
- difficulty concentrating, memory problems, brain fog, sleep disturbances or insomnia, inner restlessness, loss of appetite or constant appetite, tingling of the limbs, headaches or migraine, tiredness, dizziness, fatigue
Other symptoms:
- facial swelling or other tissue swelling, red eyes, tightness in the throat, menstrual problems, increased PMS symptoms [6]

Fig. 2: Skin redness, acne and strong reactions to insect bites are among the symptoms of histamine intolerance.

Histamine can affect the psyche – histamine and depression

Histamine intolerance itself is not a psychiatric disorder, but it can cause psychological symptoms when histamine levels are too high. Depression can even be linked to a disturbed histamine balance, as a study by Dr Parastoo Hashemi at the Imperial Department of Bioengineering in London shows. His work demonstrates that histamine is a key player in depression, because it interacts directly with the feel-good hormone serotonin. When histamine levels rise, serotonin decreases. This is exactly what happens when there is inflammation in the body. [7] When histamine levels fall again, serotonin release restarts. [8]

How to find out whether you suffer from histamine intolerance

The author and specialist in autoimmune diseases Dr Becky Campbell addresses in her guide to histamine intolerance essential questions that can help you determine whether you may be histamine intolerant:

Do you feel tired after sugary foods?
Do you suffer from migraine?
Do you suffer from anxiety or panic attacks?
Do you experience unwanted symptoms after certain foods?

If you answered “yes” to these four questions, you should investigate further. Dr Campbell lists additional questions in her book that you can pursue and also outlines possible solutions.

Fundamentally, making an exact diagnosis is challenging, because the symptoms can resemble those of other diseases. The symptoms can also be very diverse and any organ system may be affected. [9]

How can the diagnosis be made?

The diagnosis is made by measuring the histamine level and the histamine‑degrading enzyme diamine oxidase (DAO) in the blood. DAO is continuously released into the bloodstream and is therefore a suitable marker for determining histamine levels. For the DAO measurement a blood sample is sent to a medical laboratory for analysis.

This test is repeated after 2 weeks following adherence to a histamine‑free diet. If histamine intolerance is present, not only should the symptoms have improved significantly, but the histamine level should also have fallen by at least half while DAO is increased. [10]

Another diagnostic approach is a so‑called differential diagnosis. In this process other conditions are ruled out. This means that allergies, other intolerances, autoimmune diseases or mast cell activation syndrome can be distinguished from histamine intolerance, because they are easier to detect. [11]

Person wearing blue gloves holding pipette, below various small filling holes

Fig. 3: A laboratory test can clarify whether histamine intolerance is present.

What are the causes of histamine intolerance?

The prevailing view among experts is that a histamine deficiency is not congenital but is acquired over the course of life and can have various triggers. [12]

In general, one can say that in histamine intolerance either too much histamine is taken in or the breakdown is not adequate. [13]

With regard to breakdown, the two histamine‑degrading enzymes diamine oxidase (DAO) and histamine N‑methyltransferase (HNMT) are lacking in histamine intolerance.

If these two enzymes cannot perform their function properly, various problems occur in the body. Depending on which enzyme is impaired, different complaints appear.

What happens when DAO is missing?

Diamine oxidase (DAO) breaks down the histamine we ingest with food. DAO also breaks down allergen‑related histamine excess. A DAO deficiency therefore tends to cause symptoms such as flushing, nausea, headaches, a sensation of heat and shortness of breath, but above all diarrhoea. Eczema, rhinitis, urticaria attacks, hypertension, colitis and asthma can also result. [14]

What happens when HNMT is missing?

A deficiency in the enzyme HNMT tends to lead to chronic forms of histamine intolerance in which the nervous system is usually affected. The consequences are therefore neurologically based, such as restlessness, muscle twitches, sleep disturbances, tiredness, dizziness and anxiety. [15]

1. Trigger: Diet

Poor diet:

One of the triggering factors for histamine intolerance is thought to be diet: too much sugar, too much white flour, meat, animal fat, dairy products, stimulants or alcohol. Such a poor diet leads to an imbalance in the gut with the “wrong” bacteria. Toxin‑producing, anaerobic bacteria and fungi spread and damage the natural barrier function of the intestinal mucosa. [16]

Histamine‑rich diet:

Above all, an excess of histamine taken in with food puts the body in a bind – it can lead to so‑called histamine poisoning. Historically, histamine poisoning has also been called scombroid fish poisoning or mahi‑mahi intoxication, as it has repeatedly been caused by the consumption of fish from the Scombridae and Scomberesocidae families (e.g. tuna, herring and mackerel). Tuna in particular is associated with histamine poisoning. [17]

Beware of E‑numbers:

Additives, the so‑called E‑numbers used by the food industry, also increase the release of histamine in the body. [18]

Be careful with gluten:

Gluten is the glue protein found in many cereals, especially wheat and rye but also kamut, and is per se an inflammation‑promoting substance. Gluten is furthermore seen as a possible trigger for leaky gut syndrome, which in turn can trigger histamine intolerance. You can be tested for gluten intolerance and leaky gut. [19]

2. Trigger: Prolonged stress

Not only diet but also stress can lead to histamine intolerance. In particular, chronic stress weakens the adrenal glands. This in turn leads to constant histamine release. The immune system and organ systems are thereby adversely affected.

Stress triggers so‑called mast cells (large cells involved in regulating the immune response). These release the histamine stored within them, leading to an increased histamine concentration. Originally this was important for humans because it triggers the fight‑or‑flight response to react to danger. Histamine binds to specific receptors in the nervous system, which causes even more adrenaline to be released. This keeps our stress level elevated – whether the stress is “positive” or “negative”. Stress management strategies such as meditation or yoga can help interrupt this cycle. [20]

3. Trigger: Medications – they affect the breakdown of histamine in the body

Many medications affect the breakdown of histamine in the body. They can sometimes delay it and thereby trigger severe reactions. This particularly concerns pain and rheumatism drugs such as Mefenacid, diclofenac, indometacin and acetylsalicylic acid (aspirin). Fenbrufen, levamisole and ibuprofen, on the other hand, are generally well tolerated. Radiological contrast media release histamine and can be dangerous for people with histamine intolerance. [21] The effects of pharmaceuticals and their potential to induce histamine intolerance were described scientifically in this study. [22] These include:

contrast media
muscle relaxants
analgesics
local anaesthetics
antihypotensive agents
antihypertensives
antiarrhythmics
diuretics
drugs that affect gut motility
antibiotics
mucolytics
bronchodilators
H2‑receptor antagonists
antidepressants

If you are taking one or more medications from these categories and experience symptoms of histamine intolerance, you should discuss this with your doctor.

4. Trigger: Disturbed intestinal metabolism, intestinal infections and microorganisms

Leaky gut:

The gut plays a decisive role in a balanced histamine level, for example in leaky gut syndrome, where tiny holes in the intestine can cause symptoms and produce a DAO deficiency. DAO, alongside HNMT, is the enzyme that breaks down histamine in the human body.

Candida:

Candida is a common cause of histamine intolerance. Overgrowth of this fungus can result in leaky gut. Signs of Candida overgrowth include cravings for sweets or bad breath, chronic fatigue and brain fog. Candida can also trigger histamine release by causing the immune system to react to the pathogenic overgrowth with histamine release. You can be tested for a Candida imbalance. [23]

Person holds their stomach

Fig. 4: A gut overgrowth with Candida albicans can worsen histamine intolerance.

Intestinal infections:

Although research is still in its infancy here, a link between the bacterium Helicobacter pylori and histamine release has already been observed. [24] This bacterial strain triggers increased histamine production in mast cells. At the same time, H. pylori makes the intestinal mucosa more permeable, allowing undigested food to pass through and potentially trigger allergic reactions. It is therefore important to be tested for H. pylori.

5. Trigger: Nutrient deficiencies

A deficiency in certain vitamins can also mean that DAO is not sufficiently available to break down histamine. Copper and vitamin C are essential for DAO formation. Vitamin B6 helps to break down histamine. Zinc, as an anti‑inflammatory trace element, also plays an important role. [25]

The 4‑phase reset plan according to Dr Becky Campbell

There are people who have to suffer from undetected histamine intolerance for many years. Unexplained symptoms burden patients, because diagnosing histamine intolerance is not straightforward and is multi‑faceted. The naturopathic physician and author Dr Becky Campbell recommends a 4‑phase approach as a direct route to greater wellbeing. [26]

Phase 1: Dietary change

In the first phase histamine‑rich and inflammation‑promoting foods should be avoided. This phase lasts between 1–3 months. A food diary should be kept to draw conclusions. In general Dr Campbell recommends less protein and more vegetables or alternatively a paleo diet. This is a way of life that emphasises anti‑inflammatory foods. Coffee should be avoided.

Phase 2: Liver cleanse

The second phase focuses on cleansing the liver. Dr Campbell recommends Epsom salt baths with magnesium sulfate or castor‑oil liver packs to help eliminate toxins. She also suggests liver‑cleansing supplements such as milk thistle, N‑acetyl‑L‑cysteine (NAC) and artichoke.

Phase 3: Gut cleanse

For the third phase Dr Campbell recommends a thorough gut cleanse. “An imbalance in the gut has been linked to autoimmune diseases, anxiety, depression, skin problems and hormonal disturbances.”

Phase 4: Reintroduce histamine‑rich foods

After the diet and the liver and gut cleanses, you can experiment a little more. Certain histamine‑rich foods can be reintroduced into the diet to determine whether symptoms occur.

You will find detailed information on all four phases in Dr Campbell’s book. She presents a variety of low‑histamine recipes that allow you to eat healthily and enjoyably even while dieting.

Do not be discouraged: take your diet and thus your wellbeing into your own hands. Experiment with low‑histamine dishes, cook with joy and observe how your sense of wellbeing changes.

Disclaimer

If you suffer from the symptoms described, it is advisable to have a histamine test performed by your doctor or a laboratory of your choice.

This article does not replace treatment by a qualified practitioner. The basis of this article is studies and current literature. It must not be used for self‑diagnosis or self‑treatment. Discuss any inspirations from this article with a practitioner you trust.