Histamine intolerance: the often unrecognised intolerance

A lovely evening with friends over a few glasses of wine and a big cheese board… and afterwards you are troubled by stomach ache, a racing heart or an itchy rash with hives. One possible cause: an intolerance to foods that contain or trigger histamine, known as “histamine intolerance”. Most people know the term… very few know what lies behind it. We explain it in this article.

Histamine is a biogenic amine. Translated, that means: a protein substance that occurs quite naturally in our body, for example in very many types of tissue, above all in the skin, lungs, stomach, gut and the diencephalon.

It is a true all rounder. As a tissue hormone it supports the muscle contractions in the airways or the intestinal tract. In allergic reactions it provides immune defence. As a neurotransmitter (a messenger substance in the brain) it influences various factors such as the sleep/wake rhythm, our appetite and also the learning abilities and emotions of our memory. The list is endless. So in itself, histamine in our body is very much a good thing.

Histamine is formed in what are known as mast cells (special white blood cells) and is produced from amino acids with the help of certain enzymes (decarboxylases). These enzymes occur in bacteria and in human, animal and plant tissue. That means histamine can be produced in humans themselves, but it can also form in, or be contained in, animal and plant foods.

And nature regulates it so neatly: when histamine is no longer needed by the body, the enzyme diamine oxidase (DAO) breaks it down in the small intestine. A classic cycle that regulates itself.

Histamine is one of the body’s own messenger substances and sets off a wealth of follow-on reactions in the organism. It mainly influences the blood vessels, the bronchi, the stomach lining and the central nervous system. As a signal transmitter, histamine also puts the body on alert during infections and allergic reactions.

Histamine occurs in some plant foods, for example spinach, tomatoes, avocados and strawberries. In addition, perishable animal foods such as fish that are contaminated with the relevant microorganisms also contain histamine. Foods that are produced by fermentation do too, and these include cheese, sausage, sauerkraut, yeast extract, wine and beer. Slowly ripening sausages and cheeses (raw cured sausage and Emmental) contain higher histamine levels than, for example, Gouda.

Histamine intolerance (HIT) is also called histamine incompatibility or histaminosis. People who suffer from HIT cannot tolerate histamine or other biogenic amines (for example serotonin, tyramine or phenylethylamine). Symptoms appear when there is an imbalance between histamine intake, histamine production and histamine breakdown, in other words when the body no longer produces enough DAO, for example, or when you take in so much histamine through food that the system simply cannot manage the breakdown any more. Every person has a different tolerance threshold. A value between 0.3 and 1.0 nanograms per ml is regarded as normal. However, complaints can also start at lower values, or only at higher ones. The further the histamine level rises, the more severe the symptoms become.

It is impossible to pin down a single cause of histamine intolerance. Several triggers play a role in the development of HIT, and it is rarely down to the mere intake of individual histamine rich foods. The following factors can lead to histamine intolerance in combination:

• Eating histamine rich food, histamine liberators or other biogenic amines, for example by eating ripe bananas or spinach
• An allergy, a pseudo allergy or mastocytosis (changes in the mast cells and in the number of mast cells)
• Inhibition or a deficiency of the enzyme diamine oxidase (DAO) in the gut, which is responsible for breaking histamine down
• Excessive alcohol consumption: alcoholic drinks either contain histamine themselves or they increase the permeability of the gut to histamine
• Infections or inflammation that lead to increased permeability of the gastrointestinal lining

The symptoms often resemble those of other conditions. The spectrum ranges from digestive complaints all the way to breathing difficulties. On top of that, tiredness or exhaustion can occur more often. Frequently, though, a food intolerance such as fructose malabsorption can also be behind it. Symptoms that can be signs of histamine intolerance once other intolerances or allergies have been ruled out include:

• A feeling of fullness
• Diarrhoea
• Period pain
• Headaches and migraine
• Skin reactions (hives and swelling)
• Shortness of breath and asthma like complaints caused by narrowing of the bronchi
• Circulatory complaints
• A blocked nose
• Abdominal cramps
• increased production of gastric acid

Triggers are substances or mechanisms that can intensify the symptoms of histamine intolerance. One example is histamine liberators (substances taken into the body from outside that release histamine within the body). They do not themselves contain large amounts of histamine or other biogenic amines, but they cause the body’s own histamine to be released from the mast cells. That produces symptoms which look as though you had eaten something containing histamine. Histamine liberators include certain medicines (for example aspirin) as well as food additives such as azo dyes, flavour enhancers or preservatives. Histamine liberators are also found here and there directly in foods, for example in citrus fruit or seafood, tomatoes and strawberries. Fish and meat also contain biogenic amines. These inhibit the enzyme activity of DAO and get in the way of the body breaking histamine down completely. There are indications that hormones can also influence how well histamine is tolerated. Women who are shortly before their period often tolerate histamine rich food considerably less well than on the remaining days of the month. The reasons, however, have not yet been researched sufficiently.

Depending on the symptoms, various conditions that have nothing to do with histamine intolerance may be the explanation. In the case of circulatory problems, an allergy to a particular food could be the cause of the complaints. A runny or blocked nose could be allergic rhinitis, and with shortness of breath you should first be checked for asthma. Nausea and diarrhoea are usually classic signs of gastrointestinal conditions such as stomach ulcers, lactose intolerance or fructose malabsorption. In every case a doctor should be brought in for the diagnosis, for example your GP.

A diagnosis of histamine intolerance is a diagnosis by exclusion. There is no single clear parameter that would allow this intolerance to be identified reliably. That is why allergies or any other food intolerances have to be ruled out first. To find out whether the complaints are due to histamine intolerance, either a provocation test or an elimination diet can be carried out at the doctor’s.

How does a provocation test work?

In a provocation test the patient is given a very high dose of histamine. This is done in the form of a histamine solution that is served in a drink. Other drinks that contain no histamine are provided alongside it, so that it can then be established which of the drinks the patient reacts to with symptoms.

How does an elimination diet work?

An elimination diet serves to establish the connection between eating certain foods and the appearance of complaints. At the start it is important that foods containing histamine are avoided completely. Afterwards, foods can gradually be reintroduced into the diet with support.

Overall the rule is: the histamine content can change, and the riper and older a food is, the more histamine it probably contains. One example: fish straight from the catch is low in histamine. If it is not kept cool, its histamine content rises quickly. Vegetables and meat are also (with few exceptions) usually low in histamine in their original form. Through pickling (preserving), souring, fermentation or longer storage, however, they can develop into veritable “histamine bombs”. So the fresher you eat something, the better it is tolerated by people with histamine intolerance. The foods should also generally be free of flavour enhancers (glutamate E 620-625), because these hinder the breakdown of histamine in the body. In the same vein you should also do without yeast and yeast extract as well as other flavour enhancers, stock, chilli and other hot spices, vinegar (including balsamic and wine vinegar) or soy sauce.

It is also important to pay attention to the amount eaten and to the way it is prepared. Eating or using foods straight from the fridge, rather than letting them warm up to room temperature, prevents larger amounts of histamine being taken in. Reheating fish and meat dishes in the microwave or the oven makes the histamine content rise. To stop foods becoming “old”, it makes sense to freeze them while they are fresh.