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What is Histamine Intolerance?

Histamine is a chemical best known for its role in triggering an allergic reaction. During this type of reaction, the source of histamine released is from cells known as mast cells.


Histamine intolerance (HIT) is also mediated by histamine, but is caused by an inability of the body to metabolise histamine efficiently.  With HIT, the source of histamine is from food which is either high in histamine or capable of liberating histamine in the body.


Foods which are high in histamine include: 

Champagne, red wine, beer, cider and other fermented drinks and spiritsTinned and smoked fish (tuna, salmon, herring) and crustaceans
Sauerkraut and other pickled foodsMushrooms and Quorn
Vinegar and vinegar-containing foods (dressings, pickles, mayonnaise, ketchup, mustard)Seeds and nuts
Tofu and soya sauceDried fruit
Parmesan cheese and other cheesesYeast extract, yeast
Sausages and other processed meats (ham, salami, gammon, bacon)Chocolate, cocoa, cola


Foods which also encourage the release of histamine within the body include:

AvocadoNutsRed prunes
Egg whitePeanutsStrawberries


Under normal circumstances, when histamine-rich / histamine-liberating foods are eaten, excess histamine is broken down by specific enzymes and removed from circulation.  One of the main enzymes involved in the breakdown of histamine is diamine oxidase (DAO).

If a person is deficient in the DAO enzyme they will be unable to metabolise histamine efficiently.  As a consequence, when histamine-rich / histamine-liberating foods are consumed, excessive amounts of histamine can accumulate in the lungs, skin and colon, primarily.

This build-up of histamine can then trigger the onset of symptoms commonly associated with HIT, which can appear very allergy-like.  Understandably, the initial symptoms may be confused as being due to an allergic reaction, but once this has been ruled out, it is possible that HIT may be the culprit.


Symptoms of Histamine Intolerance

Typical symptoms include:

• Asthma 
• Digestive tract problems including diarrhoea and bloating
• Dysmenorrhea (painful periods)
• Eczema
• Fatigue
• Flushing (face and chest)
• Headaches
• Hypotension (low blood pressure)
• Itchiness
• Runny nose
• Skin rashes
• Swellings (mostly around the eyes and lips)
• Symptoms resembling anxiety / panic attacks
• Tachycardia
• Weepy eyes


Diagnosing HIT
Until recently, the conventional method for diagnosing HIT was to adopt a low-histamine diet and then observe if symptoms improve.  However, following a low-histamine diet can be very restrictive, especially as it requires you to avoid healthy foods.   Being able to test for histamine intolerance can, therefore, provide assurance that you are restricting your diet for good reason.


CNS Laboratory Test
Utilising proven ELISA-based technology, the DAO Screen test offers a convenient and reliable method to detect circulatory levels of DAO in the bloodstream.


Sample Requirements
Requesting a test is straightforward and convenient.  Simply collect a Dried Blood Spot sample using the components provided in the Sample Collection Pack and send to the CNS Laboratory using the pre-paid envelope supplied.  Please refer to 'Taking the Test' for more detailed instructions.
Before taking the test, it is important that you:

•  Stop using anti-histamine medication for at least 1 week, unless this has been recommended by your doctor
•  Avoid following a low-histamine diet
•  Avoid fasting

The test is not suitable for pregnant women as DAO levels increase during pregnancy.


Test Results
A test report that details the DAO concentration detected in the blood sample will be available within 15 working days. 


When you have been found to have a low DAO concentration in your blood, initial treatment will focus on reducing the intake of histamine through the diet.  Following such a diet can be quite complex, so we strongly recommend that you seek advice from a suitably qualified nutritional therapist or healthcare professional before making changes to your diet.


Important Information

Our tests are not a substitute for seeing your doctor, especially if you are suffering symptoms.We can interpret your results based on the information you have provided, but will not diagnose, consult or provide any treatment. You will be advised to see a nutritionist or doctor for any necessary follow-up action.

Histamine Intolerance

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