Histamine is a natural substance in the body, important for digestion, immunity and the brain. It is also present in food, mainly in aged, fermented and preserved foods. Some people seem to have trouble handling the histamine they eat and report a wide range of symptoms. This picture, called histamine intolerance, is still poorly defined and calls for careful investigation before any restriction.
In short
- Histamine intolerance is an imbalance between the histamine ingested or produced and the ability to break it down, mainly by the DAO enzyme.
- Symptoms are varied and nonspecific, and may have many other causes. It cannot be self-diagnosed.
- Before restricting foods, allergies, mastocytosis and digestive diseases need to be ruled out.
- The low-histamine diet is a temporary test, followed by reintroduction, not a lifelong plan.
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What histamine is
Histamine is a bioactive amine made from the amino acid histidine. The body stores it mainly in immune cells (mast cells and basophils), the stomach and the nervous system, where it also acts as a neurotransmitter.
- It stimulates acid production in the stomach.
- It takes part in inflammation and the allergic response.
- It dilates blood vessels and contracts smooth muscle.
- It acts in the brain, in wakefulness and the sleep cycle.
Besides the histamine the body makes, there is histamine in food, which forms when bacteria convert histidine during aging, fermentation and preservation.
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What histamine intolerance is
Normally, histamine from food is broken down in the gut by an enzyme, diamine oxidase (DAO). When the histamine ingested or produced exceeds the ability to break it down, it can reach the bloodstream and cause symptoms in some people.
Lower DAO activity
It can occur due to genetic factors, gut inflammation or damage, and medicines that inhibit the enzyme, such as some anti-inflammatories, antidepressants and antibiotics. Alcohol also impairs histamine breakdown.
Excess histamine or other amines
Foods rich in histamine and in other biogenic amines, such as tyramine, putrescine and cadaverine, compete for the same breakdown pathway and can add up.
Gut microbiome
Some bacteria produce histamine when they ferment food, and an imbalanced microbiome and bacterial overgrowth can raise that production. On the other hand, some probiotic strains may help and others may produce histamine: the choice should be individualized.
Histamine intolerance is not an allergy. In allergy, the immune system makes antibodies against a specific food and can cause serious reactions. The diagnosis of intolerance still has no definitive test and is a matter of scientific debate.
03
Associated signs and symptoms
The symptoms described are very varied, affect several systems and can have other causes. They do not prove histamine intolerance:
Skin
Itching, hives, redness, eczema and swelling of the face or other areas.
Eyes and airways
Red, itchy eyes, runny or blocked nose, sneezing and symptoms like those of rhinitis.
Digestion
Abdominal pain, bloating, diarrhea, nausea, vomiting and reflux.
Heart and circulation
Palpitations, fast heartbeat, dizziness, a drop in blood pressure on standing and sensations of heat or cold.
Brain and mood
Headache and migraine, difficulty sleeping, irritability, anxiety and brain fog.
Menstrual cycle
More intense cramps and premenstrual tension in some women.
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How the investigation works
No single test confirms the intolerance. The diagnosis is one of exclusion and takes into account symptoms, history and response to diet:
1. Rule out other causes
Food allergies (with an allergist's evaluation and tests such as the skin prick test or IgE measurement), mastocytosis, celiac disease, inflammatory diseases, SIBO and other digestive conditions, as well as the effects of medicines.
2. Food and symptom diary
Write down what you ate, at what time and which symptoms appeared. This shows patterns, such as a link with alcohol, aged cheese or leftovers.
3. Low-histamine diet, for a limited time
Usually 2 to 4 weeks, and at most the time set by the professional. If there is no improvement, the diet should be stopped and the cause of symptoms reassessed.
4. Gradual reintroduction
Foods are reintroduced one by one, watching for reactions. The diagnosis is likely if symptoms improve on the diet and return with reintroduction.
Lab and genetic tests
Blood DAO measurement and DAO gene polymorphism tests can be used as complementary information, but have no diagnostic value on their own: an altered result does not prove the intolerance, and a normal one does not rule it out.
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Most cited foods
Histamine content rises with aging, fermentation and storage time. The foods most linked to symptoms are:
- Alcohol, especially red wine, beer and spirits.
- Aged and matured cheeses, and other fermented dairy.
- Cured and smoked meats: salami, ham, bacon and sausage.
- Canned or not-fresh fish and seafood, such as canned tuna, mackerel and sardines.
- Fermented and pickled foods: sauerkraut, kombucha, vinegar, pickles and soy sauce.
- Tomato, spinach, eggplant and avocado.
- Fruits such as strawberry, citrus, kiwi, very ripe banana and pineapple.
- Chocolate, cocoa, green tea and some spices, such as chili, cinnamon and cloves.
- Peanuts, walnuts and, in some cases, legumes.
Food lists vary between sources, and tolerance is individual. Not every food listed causes symptoms in everyone. So avoid cutting everything at once: professional guidance helps restrict only the minimum necessary.
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Practical tips
- Prefer fresh food and prepare it the same day.
- Avoid leftovers kept for several days: freeze portions right after cooking.
- Buy fresh meat and fish and eat or freeze them quickly.
- Reduce alcohol and talk to your doctor about medicines that inhibit DAO.
- Look after gut health: fiber, a variety of vegetables and attention to persistent digestive symptoms.
- Probiotics and DAO supplements may be tried in selected cases, but evidence is limited. Do not use them without guidance.
The low-histamine diet is restrictive and, if kept up for a long time, can cause nutrient deficiencies and harm your relationship with food. It should have a start, an end and a reassessment.
Investigate before restricting
In the consultation, I assess symptoms, tests, medicines, diet and gut health to guide a safe investigation, lead the temporary diet and reintroduction and avoid unnecessary restrictions, together with your doctor and allergist.
Dra. Daniely Catharino TooleyClinical, functional and orthomolecular nutritionist · CRN3/6794
References (4)+
- Comas-Basté et al. Histamine intolerance: the current state of the art. Biomolecules, 2020.
- Maintz & Novak. Histamine and histamine intolerance. Am J Clin Nutr, 2007.
- Reese et al. German guideline for the management of adverse reactions to ingested histamine. Allergo J Int, 2017.
- Schnedl & Enko. Histamine intolerance originates in the gut. Nutrients, 2021.
Educational content for adults. This guidance does not replace an individual consultation, diagnosis or treatment.