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The vital role of histamines in your body

Is histamine a friend or foe? If you’re susceptible to allergies and dealing with an itchy rash, you’ll probably be taking antihistamines to reduce histamine’s irritating effect on your body.

But there’s a friendlier side to histamines too. Let’s take a look.

What is histamine?

Histamine is a chemical that sends signals between the cells in your body. Among other things, histamine tells your stomach cells to make acid so you can digest food and tells your brain to stay awake. Histamine also helps to protect your body against parasites.

Histamine forms an important part of your immune system, helping protect you from foreign invaders, much like a bouncer evicting unruly drunks from a pub.

Histamine and your immune system

Generally speaking, your body balances histamine release quite well. But, when you have an allergic reaction, you release too much histamine, leading to allergy symptoms.

An allergic reaction occurs when your body overreacts to an allergen like pollen or an insect bite. It begins with your mast cells releasing histamine. Mast cells are a type of white blood cell found in connective tissues throughout your body, particularly in your skin, lungs, nose, mouth, gut and blood.

Histamine then increases blood flow to the affected area of your body – the site of a mozzie bite, for example. This leads to inflammation, which triggers other parts of your immune system to act. That might create allergy symptoms like an itchy lump or rash.

Or let’s say you’re sensitive to pollen. When you breathe it in, histamine is released, prompting your membranes to create more mucous. That, in turn, can lead to allergy symptoms such as a runny nose, sneezing or coughing. Antihistamine medications may help to ease your symptoms.

Much like a robot vacuum, histamines then dock at certain stations in your body. These are known as histamine receptors.

Histamine and foods

Histamine occurs naturally in your body. But you also consume it in certain foods including avocado, grapes and lemons.

When you eat histamine-containing foods, your body should break down the histamine through the normal process of digestion. To do that, it relies on an enzyme called diamine oxidase (DAO) and, to a lesser extent, a second enzyme named histamine-N-methyltransferase (HNMT).

DAO helps keep your histamine levels nicely balanced. But the delicate balance can be disrupted if you have too much histamine or not enough DAO. That may happen due to:

  • Genetic mutations
  • Alcohol use
  • Certain medications
  • Overgrowth of gut bacteria
  • Eating large amounts of histamine-containing foods.

When digestion fails to break down histamine, it may leak through your intestinal lining and enter your bloodstream. That can trigger high histamine symptoms such as:

  • Nausea or vomiting
  • Diarrhea
  • Bloating
  • Itching
  • Rash or hives
  • Headache
  • Runny or stuffy nose
  • Breathlessness
  • Low blood pressure
  • Irregular or fast heart rate
  • Painful periods
  • Swelling of your lips, tongue or throat.

How do you know if you’re having a histamine reaction?

It can be hard to tell whether your symptoms are due to histamine sensitivity or another cause.

You could try keeping a diary, trying to spot if your symptoms appear after eating high-histamine foods. You could try eat a low-histamine diet and seeing if you feel better. That could yield some useful information but it can be tedious and there’s a degree of subjectivity involved.

A better way may be to take ImuPro’s Histamine Intolerance Test (DAO). This is a simple blood test to reveal whether you have low or inhibited DAO, the enzyme responsible for breaking down histamine in the gut. The test results will help you understand whether your troublesome symptoms are being driven or worsened by an underlying histamine intolerance.

ImuPro’s DAO test is the only DAO test available directly to consumers in Australia. It’s a blood serum test conducted in specialised certified German laboratories.

Order your test today.

*All information is general and is not intended to be a substitute for professional medical advice. 


Cleveland Clinic, What is histamine? https://my.clevelandclinic.org/health/articles/24854-histamine, [Accessed 23 May 2024]

Medline Plus, Histamines: The stuff allergies are made of? https://medlineplus.gov/medlineplus-videos/histamine-the-stuff-allergies-are-made-of/#, [Accessed 23 May 2024]

WebMD, What are histamines? https://www.webmd.com/allergies/what-are-histamines, [Accessed 23 May 2024]

Healthline, What is DAO? Diamine oxidase supplements explained, https://www.healthline.com/nutrition/dao-supplement, [Accessed 23 May 2024]

Medical News Today, Which foods are high in histamine? https://www.medicalnewstoday.com/articles/322543, [Accessed 23 May 2024]

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