Histamine intolerance

Histamine intolerance is when the body cannot break down histamine and therefore histamine levels are high.
Hypersensitivity to histamine is a complex phenomenon and cannot be detected by IgE/IgG-based allergy and intolerance tests.
Histamine is both produced by the body and ingested through food.
Diamine oxidase (DAO) breaks down histamine outside the cells and histamine N-methyltransferase (HNMT) breaks down histamine inside the cells.
The term ‘histamine intolerance’ is mainly used to describe a deficiency in the enzymes that break down histamine.

Histamine levels can be affected by a variety of diseases, inflammation, hormonal imbalances, allergies, intolerances, external factors (e.g. extreme weather, environmental pollutants, cosmetics, chemicals, intense exercise), psychological states and stress.
The symptoms and effects of histamine intolerance can vary and can be of different severity depending on the individual.

– digestive problems; – bloating; – abdominal pain; – diarrhoea or constipation; – nausea, vomiting.

– Genetics: you may have a gene mutation that causes your body to produce less DAO enzyme or the DAO enzyme does not work properly.

– Gastrointestinal (GI) disorders: GI disorders such as inflammatory bowel disease (IBD) can cause DAO deficiency.

– Bacterial overgrowth: When the body cannot digest food properly, bacteria overgrow, causing too much histamine to be produced.
Normal levels of the enzyme DAO cannot break down the increased histamine in your body, causing a reaction.

– Diet: excessive consumption of histamine-rich foods can cause the DAO enzyme to function improperly.
Some foods may block the DAO enzyme or trigger histamine release (histamine liberators).

– Menopause, micronutrient and vitamin deficiencies, and COVID/post-COVID have also been shown to affect the body’s mechanisms of histamine production and breakdown.

– Medications: some medications may temporarily block DAO or prevent DAO production.

You are more likely to develop histamine intolerance if you have a gastrointestinal disorder, such as:

– colonic polyps; – malabsorption; – food allergy, food intolerance; – coeliac disease; – IBD such as Crohn’s disease or ulcerative colitis; – irritable bowel syndrome (IBS); – functional dyspepsia; – contaminated small bowel syndrome (SIBO).

Diagnosing histamine intolerance is not an easy task, as the symptoms can be very similar to those of other conditions (infections, allergies, digestive diseases, inflammation, etc.), so it is essential to rule these out.

Your doctor may recommend that you follow an elimination diet for 2-4 weeks, i.e. avoid foods that are high in histamine or release histamine, and then gradually introduce them back one at a time, monitoring your reactions.

The doctor may ask for a DAO enzyme test in the blood to analyse whether there is a DAO deficiency.
(They cannot test for HNMT).
DAO level measurement is the most common diagnostic tool in current practice, but it can be wrong in a healthy person or DAO production can be acutely affected by other conditions.
Many people also recommend, as additional information to DAO, the measurement of plasma histamine concentrations, which can be affected by a number of conditions throughout the day and can also be good even in the presence of symptoms.
These test results alone are therefore not reliable indicators of histamine intolerance and should be evaluated in conjunction with symptoms, personal dietary experiences and other medical conditions to make a diagnosis.

If you think you may have a histamine intolerance or are experiencing irregular symptoms, talk to your doctor.

A healthy diet contains moderate levels of histamine.
Some foods high in histamine can cause reactions even in healthy people.
A key issue in the histamine diet for foods and prepared foods is their freshness, as a lot of histamine is released not only during fermentation, ripening and smoking, but also during storage.
This is particularly important for meat and fish.

In case of suspected or diagnosed histamine intolerance, it is important to investigate possible inflammations (gastrointestinal, dental, gynaecological, etc.), infections, intolerances, autoimmune diseases and other disorders, because if conditions that undermine the health of the gut or inhibit the function of histamine-degrading enzymes are not treated, histamine diet alone may not lead to satisfactory results.

More research is needed to prove the benefits of a histamine-restricted diet.
The diet can bring significant improvements in the short term, but in the medium to long term it is also essential to supplement vitamins and trace elements, regenerate the digestive system and gut flora, manage stress and sleep.

– alcohol and other fermented beverages; – fermented foods and dairy products, such as yoghurt and sauerkraut; – dried fruit; – avocados; – aubergines; – spinach; – processed or smoked, cured, dried meats; – preserved fish and shellfish; – cured cheeses; – yeast and products made from yeast.

– alcohol; – bananas; – tomatoes; – wheat germ; – beans; – papaya; – chocolate; – citrus fruits; – nuts, in particular walnuts, cashew nuts and peanuts; – food colours and other additives; – non-fresh fish; – pork.

– alcohol; – black tea; – mate tea; – energy drinks.

Studies and lists of low histamine diets can vary considerably in the list of foods to avoid or consume and their histamine content.
Even knowing the recommendations, it is important to monitor your individual tolerance by trying to identify and eliminate foods that cause symptoms or discomfort to see if elimination changes your condition.

You should always consult a specialist before making radical dietary changes.
If you suffer from histamine intolerance, a low histamine diet can go a long way towards controlling or eliminating your symptoms.
Antihistamines can relieve symptoms in the short term.
Occasionally, if you are visiting, travelling or deviating from your usual diet, you may take DAO enzyme replacement tablets before meals, but frequent use of these is not a substitute for a low histamine diet.