Histamine intolerance
Histamine and histamine intolerance is a topic of increasing interest, especially because it is often misdiagnosed with IBS. The purpose of this article is to shed light on histamine intolerance, common symptoms, diagnosis, and therapeutic approaches.
This is part 1 of the series on Histamine. Read part 2: The connection between histamine intolerance and the gut microbiome , and part 3: Histamine and Irritable Bowel Syndrome (IBS) to gain a greater understanding of histamine and histamine intolerance.
What is histamine?
Histamine is a signaling molecule that communicates with cells throughout the body, including the brain, digestive system, and immune system. Histamine is produced and stored naturally in the body (primarily by white blood cells: mast cells and basophils), and is also a component of some types of foods, such as fermented products, alcohol and aged cheese.
In the right amounts, histamine has beneficial effects in the body, such as promoting the production of stomach acid, regulating appetite, influencing the body's homeostasis regulation (e.g. temperature), hormone function, cell growth and influencing the sleep cycle . Furthermore, histamine is released as an immune response. When the body feels threatened (e.g. by pollen, food or dust), histamine is released and acts through its four receptors (located in the brain, nose, chest and gut). This causes other systems in the body to respond to protect it from the threat.
Maintaining healthy levels of histamine in the body is ensured by two enzymes: diamine oxidase (DAO) and histamine N-methyltransferase (HNMT) . However, if there is an imbalance between the levels of histamine in the body and the ability to break down the large amounts, the high levels of histamine can affect the body's normal functions. Too much histamine results in overactive receptors, which causes allergy-like symptoms , known as histamine intolerance.
Histamine intolerance (HIT)
The symptoms of histamine intolerance can vary, but usually occur after consuming foods containing histamine at levels that do not normally cause symptoms in a healthy person.
Common symptoms associated with HIT include :
- Gastrointestinal symptoms: nausea, vomiting, constipation, abdominal pain and bloating
- Headaches and migraines
- Nasal symptoms: stuffy, runny or itchy nose, sneezing
- Skin irritation: itchy skin, rash, reddened skin
- Low blood pressure
- Menstrual pain
How do we get too much histamine in the body?
Excessive levels of histamine in the body are usually caused by a reduced amount or impaired function of DAO, resulting in an ineffective breakdown of histamine. Genetic factors, diseases such as IBS, IBD, an inhibitory effect of alcohol and some types of medications can cause DAO deficiency or reduce its function.
Histamine levels in foods can vary even within the same products, and are therefore difficult to measure. Here are some foods that typically contain higher amounts:
- Fermented foods, including sauerkraut, kimchi, and yogurt
- Alcohol and fermented beverages
- Processed meats, including sausage, salami, smoked and cured meats
- Aged cheeses
- Citrus fruits
- Spinach, avocado, eggplant
- Fish and seafood
- Vinegar
Diagnostics
Histamine intolerance and its symptoms can vary greatly between people and even within the same person. It is currently difficult to diagnose HIT clinically, as standardized diagnostic tests are still lacking.
In the absence of a validated diagnostic method, a diagnostic approach is recommended:
- Rule out potential factors that may influence HIT or symptoms: Food allergies, medications that affect DAO activity, intestinal diseases (e.g., IBS, IBD), systemic mastocytosis (too many mast cells)
- Confirm the diagnosis of HIT: In the presence of two or more symptoms that improve by following a low-histamine diet, HIT is confirmed.
- It is recommended to record all foods and experienced symptoms for 24 hours to determine any association between food and symptoms. A 4-8 week low-histamine diet is then recommended.
- Supplementary tests are relevant in some cases: determination of DAO activity, histamine test (oral), histamine test (skin prick), test of genetic factors, test of histamine metabolites (methylhistamine) in urine and feces.
Histamine intolerance and food allergy - what's the difference?
Food allergies, food intolerances and histamine intolerances often cause similar symptoms and are therefore easy to confuse. However, food allergies affect the immune system, with small amounts of food triggering symptoms, whereas food intolerances simply affect the digestive system and cause less severe symptoms.
Histamine intolerance, on the other hand, is not just a sensitivity to histamine-containing foods, but symptoms that develop when the body is unable to break down the amounts present in the body.
Therapeutic treatment of HIT
Among the therapeutic approaches for HIT, the golden standard is a low-histamine diet, which excludes foods with high histamine content for a period of time. By removing high-histamine foods from the diet, and then adding them back one at a time, you can find out which foods cause symptoms.
In addition to diet, it is important to investigate any effects medications may have on the effects of histamine and DAO, and change them if necessary.
In some cases, a DAO supplement is recommended as an additional treatment to support the breakdown of ingested histamine.
In general, there is not yet a clear consensus among experts on specific dietary recommendations for HIT. However, it is recommended to avoid the consumption of hard and semi-hard cheeses, fatty fish, shellfish, fermented meat products, pickled vegetables, fermented soy products, alcohol, chicken, eggs, chocolate and mushrooms. Meat and fish should only be eaten fresh. In addition, vegetables and fruits such as spinach, tomatoes, citrus fruits, strawberries, eggplant, avocado, papaya, bananas, kiwi, pineapple and plums should be avoided because they can stimulate the release of histamine in the body.
Key messages
- Histamine intolerance (HIT) is currently a clinical field of increasing interest. It occurs due to the consumption of histamine-rich foods, mainly caused by a deficiency of the DAO enzyme at the intestinal level and thus insufficient degradation.
- The clinical diagnosis of HIT remains challenging due to the lack of standardized diagnostic tests.
- New knowledge and scientific research have helped to clarify much about HIT, but future studies are needed to optimize individual treatment.
Author: Ingeborg Amble Holtmann
