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Histamine Intolerance

Histamine is a chemical compound that is naturally produced by the body and plays a role in various physiological processes. It acts as a neurotransmitter, regulates stomach acid production, and is involved in the immune response.

Histamine is also found in certain foods and is released during allergic reactions and inflammation. It can cause symptoms such as itching, redness, swelling, congestion, and digestive issues when it binds to histamine receptors in the body.

Some individuals with IBS may also experience symptoms related to histamine intolerance. These can include abdominal pain, bloating, diarrhea, nausea, and other digestive issues.

Certain foods high in histamine or that trigger the release of histamine, such as aged cheese, fermented foods, and alcohol, may exacerbate symptoms in these individuals.

Histamine Intolerance & Small Intestinal Bacterial Overgrowth (SIBO)

There is a relationship between histamine and SIBO. SIBO is a condition characterised by an overgrowth of bacteria in the small intestine, which can lead to various digestive symptoms.

In some cases, SIBO can contribute to histamine intolerance. This occurs because certain bacteria in the small intestine can produce histamine as a byproduct of their metabolism.

When there is an overgrowth of these histamine-producing bacteria, it can lead to an increase in histamine levels in the body, overwhelming the body's ability to properly metabolise and clear histamine. This can result in symptoms of histamine intolerance.

Additionally, SIBO can also affect the integrity of the gut lining, leading to increased gut permeability or "leaky gut." This can further contribute to histamine intolerance as histamine can pass through the compromised gut barrier and enter the bloodstream, triggering an immune response and inflammatory symptoms.

Addressing SIBO through appropriate treatment, such as antimicrobial therapy and dietary modifications, can help reduce the overgrowth of bacteria and subsequently improve histamine intolerance symptoms.



Testing for histamine intolerance can be challenging as there is no definitive medical test available.

However, healthcare professionals may use a combination of approaches to assess histamine intolerance. These may include:

  • Symptom Assessment: A thorough evaluation of your symptoms and medical history can help identify patterns consistent with histamine intolerance. Symptoms such as headaches, flushing, hives, nasal congestion, gastrointestinal disturbances, and other allergic-like reactions after consuming histamine-rich foods may indicate histamine intolerance.

  • Elimination Diet: An elimination diet involves removing high-histamine foods and other potential triggers from your diet for a period of time, typically 2-4 weeks, and then gradually reintroducing them while monitoring symptoms. This can help identify specific food triggers that may be contributing to histamine intolerance symptoms.


  • DAO Enzyme Testing: Diamine oxidase (DAO) is an enzyme responsible for breaking down histamine in the body. Low levels of DAO can contribute to histamine intolerance. Testing DAO enzyme activity through blood or urine samples may provide some insight into your ability to metabolize histamine.

It's important to consult with a healthcare professional experienced in histamine intolerance to determine the most appropriate testing methods for your specific situation. They can guide you through the process and help interpret the results to develop an individualised treatment plan.

Histamine intolerance can cause a wide range of symptoms, which can vary in severity from person to person. Some common symptoms of histamine intolerance include:

  • Digestive symptoms: Abdominal pain, bloating, diarrhea, constipation, nausea, and vomiting.

  • Skin symptoms: Itching, hives (urticaria), redness, flushing, and eczema.

  • Respiratory symptoms: Runny or congested nose, sneezing, coughing, wheezing, and difficulty breathing.

  • Headache: Migraines or tension headaches.

  • Fatigue: Feeling tired or lacking energy.

  • Cardiovascular symptoms: Rapid heart rate, low blood pressure, and heart palpitations.

  • Mood changes: Anxiety, irritability, and mood swings.

  • Sleep disturbances: Difficulty falling asleep or staying asleep.

  • Menstrual symptoms: Menstrual cramps and increased symptoms during the menstrual cycle.

  • Generalized symptoms: Brain fog, dizziness, joint pain, and muscle aches.


Mould exposure can potentially contribute to histamine intolerance due to the production of mycotoxins by certain types of mould.


Mycotoxins are toxic substances produced by moulds and can trigger an immune response in the body, leading to inflammation and the release of histamine.

In individuals who are already susceptible to histamine intolerance, exposure to mould and mycotoxins can further increase histamine levels and worsen symptoms.

Additionally, some moulds, such as Aspergillus and Penicillium, can directly produce histamine.



Histamine intolerance can have various underlying causes, and identifying and addressing these causes is important for managing the condition.

Here are some potential underlying factors that can contribute to histamine intolerance:

  • DAO Deficiency: Diamine oxidase (DAO) is the enzyme responsible for breaking down histamine in the body. DAO deficiency or low levels of DAO activity can lead to an accumulation of histamine, causing intolerance symptoms. Factors that can contribute to DAO deficiency include genetic variations, gut health issues, certain medications, and nutrient deficiencies.

  • Gut Health Imbalances: The gut plays a crucial role in histamine metabolism. Imbalances in the gut microbiota, such as small intestinal bacterial overgrowth (SIBO) or gut dysbiosis, can affect the breakdown of histamine and contribute to intolerance symptoms. Inflammation and leaky gut syndrome can also lead to increased histamine levels.

  • Enzyme Imbalances: Apart from DAO deficiency, imbalances in other enzymes involved in histamine metabolism, such as histamine N-methyltransferase (HNMT) and monoamine oxidase (MAO), can contribute to histamine intolerance. Genetic variations, medications, and certain health conditions can impact the activity of these enzymes.

  • Histamine-Rich Foods and Biogenic Amines: Consuming foods that are naturally high in histamine or contain other biogenic amines can overwhelm the body's ability to break down histamine. These foods include fermented foods, aged cheeses, cured meats, alcohol, and certain fruits and vegetables.

  • Mast Cell Activation: Mast cells are immune cells that release histamine and other inflammatory compounds in response to triggers like allergens, stress, or infections. Mast cell activation can contribute to increased histamine levels and symptoms of histamine intolerance.

  • Other Health Conditions: Underlying health conditions such as SIBO, leaky gut syndrome, autoimmune disorders, chronic inflammatory conditions, and hormonal imbalances can contribute to histamine intolerance. Addressing these conditions can help alleviate symptoms.

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What Is A Low Histamine Diet?

A low histamine diet is often recommended for individuals with histamine intolerance or sensitivity. The aim of this diet is to reduce the intake of foods that are high in histamine or that trigger the release of histamine in the body.

This can help alleviate symptoms associated with histamine intolerance.

Here are some general guidelines for a low histamine diet:

  • Avoid high histamine foods: These include fermented foods (such as sauerkraut, yogurt, and kefir), aged cheeses, cured meats, smoked fish, shellfish, leftovers, and certain vegetables (such as tomatoes and spinach).

  • Be cautious with histamine-releasing foods: Some foods may not be high in histamine themselves but can trigger the release of histamine in the body. These include alcohol, citrus fruits, strawberries, chocolate, nuts, and certain spices.

  • Choose fresh foods: Opt for fresh, unprocessed foods as much as possible. Fresh fruits, vegetables, lean meats, and freshly prepared meals are generally lower in histamine.

  • Be mindful of food storage: Histamine levels in foods can increase as they age or when they are improperly stored. Ensure that foods are properly refrigerated and consumed within appropriate timeframes.

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Supplements & Histamine Intolerance

Supplements for histamine intolerance should be used under the guidance of a healthcare professional, as individual needs may vary.

Here are some supplements that are commonly recommended for histamine intolerance:

  • DAO (Diamine Oxidase): DAO is an enzyme that helps break down histamine in the body. Supplementing with DAO may help support the breakdown of histamine and alleviate symptoms. It is typically taken with meals or as directed by a healthcare professional.

  • Vitamin C: Vitamin C has been shown to have antihistamine properties and can help stabilize mast cells, which release histamine. It can be taken as a supplement or obtained from foods high in vitamin C, such as citrus fruits, berries, and leafy greens.

  • Quercetin: Quercetin is a flavonoid that has anti-inflammatory and antihistamine effects. It can help stabilize mast cells and reduce the release of histamine. Quercetin is available as a supplement and can also be found in foods like onions, apples, and berries.

  • Vitamin B6: Vitamin B6 plays a role in the production of DAO, the enzyme responsible for breaking down histamine. Supplementing with vitamin B6 may support the optimal functioning of DAO. Foods rich in vitamin B6 include fish, poultry, bananas, and chickpeas.

  • Probiotics: Certain strains of probiotics, such as Lactobacillus rhamnosus and Bifidobacterium infantis, have been shown to help regulate immune function and reduce histamine levels in the body. Probiotics can be taken as supplements or obtained from fermented foods like yogurt and sauerkraut.

If you're feeling overwhelmed and unsure of where to start in addressing your gut symptoms, don't hesitate to reach out to us. Our team is here to help you navigate through the confusion and develop a personalised treatment plan tailored to your specific needs.

We have experience in uncovering the root causes of gut issues and can guide you towards optimal gut health. Contact us today to begin your journey towards better digestive well-being.

"Heal your gut, heal your life."

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