We always tend to relate histamine with allergic reactions and runny nose during winters and the spring season. The antihistamine medications such as Benadryl become our most common resort for fighting these allergies.

Many of us never have much trouble with histamine except very occasionally. Contrary to this, people who suffer from histamine intolerance experience severe allergic reactions, mast cell activation syndrome, and other ailments that lead to high histamine levels in the body. They can’t consume probiotic supplements, fermented foods, or grass-fed meat without getting sick.

Plus, histamine doesn’t just give you a runny nose, it affects the whole body in the form of headaches, nasal congestion, restless legs, and bloating. Various enzymes such as N-methyltransferase (HNMH) and diamine oxidase supplement (DAO) help in the breaking down of histamine. If you don’t have enough DAO in your body, it can lead to rising histamine levels which can then cause the related symptoms to manifest.

In this article, we will discuss what is histamine, histamine intolerance, and how diamine oxidase supplement can help in fighting the symptoms.

What Is Histamine?

Histamine plays an essential part in the functioning of our neurological and immune systems. This chemical is a neurotransmitter, which assists the body in sending signals or messages to our brain. With the help of which we are able to digest food.

Another major function of histamine is to control inflammation in our body whenever we get injured or need healing.

For instance, a person who is allergic to mushrooms will experience a rush of histamine if they mistakenly consume mushroom. The inflammatory response of histamine will spread throughout the body such as the nose, mouth, gut, skin, and lungs.

Here are some histamine receptors and their functions:

  1. H1 Receptor: It leads to the vasodilation of vessels in the body.

  2. H2 Receptor: It helps in enhancing the heart rate and releasing acids in the stomach.

  3. H3 Receptor: It regulates the wake and sleep cycle along with appetite and nerve.

  4. H4 Receptor: It plays a major role in the inflammatory responses of your body.

Histamine Intolerance

The enzyme DAO or diamine oxidase supplement, is responsible for breaking down the histamine in our body. When this enzyme fails to do so, our body experiences an excessive concentration of histamine or histamine intolerance, which can lead to various symptoms.

Symptoms and Signs of Histamine Intolerance

  • Flushing of the neck and face
  • Headaches
  • Itching
  • Anxiety and stress attacks
  • Increased heart rate
  • Dryness in the mouth
  • Sneezing and congestion
  • Fatigue
  • Vertigo or dizziness
  • Sleeping difficulties
  • Tissue swelling
  • Low blood pressure
  • Irregular menstrual cycle

DAO Enzyme

Diamine oxidase supplement is an enzyme which breaks down histamine, after which it is excreted through the urine. It is found in the thymus, kidney, and small intestine.

When the food we consume passes through the small intestine, the diamine oxidase supplement breaks down histamine and prevents it from entering the body. For the same reason, sufficient DAO levels can prevent histamine from causing problems in our body.

However, if you have low levels of DAO or other enzymes such as HNMH, histamine levels can rise in your body quite unexpectedly. It will keep increasing and might eventually cause chronic inflammation, histamine sensitivity, or mast cell activation syndrome.

If you want to reduce histamine levels in your body, you can:

    • Avoid histamine-rich foods such as alcohol, vinegar, smoked meats, etc.


  • Consume a good diamine oxidase supplement.


  • Avoid diamine oxidase blocking supplements or foods.

Improving DAO Levels

Improving DAO or diamine oxidase supplement in the body can enhance and facilitate the proper breakdown of histamine. If you are afraid that consuming diamine oxidase supplement may increase DAO in your body, then be assured that DAO supplements don’t enter the bloodstream. They only assist your body to break down histamine.

In a recent study, 14 people showed signs of histamine intolerance. All of these people consumed diamine oxidase supplement for two weeks, 15 minutes before dinner and lunch. In total, 13 out of 14 showed improvements in at least one symptom related to histamine intolerance.

Avoid Substances That Block DAO

When you pair diamine oxidase supplement with healthy food habits, the results are significantly satisfactory. For one, try and avoid alcohol consumption, as alcohol triggers your mast cells to release histamine. When you are histamine intolerant, this trigger or reaction is extremely strong and harmful for the body. Many may have even encountered this reaction in the form of flushing after heavy drinking.

Moreover, apart from releasing histamine, alcohol blocks DAO. This means that if your alcohol consumption is significant and you have histamine sensitivity, your body will keep releasing histamine and blocking its breaking by hindering the DAO.


Histamine reaction may seem small when experienced occasionally. However, histamine sensitivity leads to various ailments and uncomfortable conditions such as chronic nasal congestion. You can ensure proper breakdown of histamine in your body by consuming diamine oxidase supplement and reducing foods and substances that trigger excessive histamine release or block DAO.