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Histamine Intolerance 101

histamine intolerance

Histamine intolerance is a complex condition that not everyone has heard about. However, it’s an important topic to discuss as it affects more people than you may think.

Before we talk about the intolerance itself, it’s important to understand what histamine is. While histamine is naturally found in certain foods, it is also a compound that is found in the cells of the body. (1) Histamine is a very important part of the immune system and also plays a role in inflammation in the body. We also need histamine in order to digest food, move our bowels, boost exercise performance, increase attention, and get blood as well as nutrients and oxygen delivered to different parts of the body. (2) With the right amount of histamine, the body is able to perform these functions as it should.

However, the problem occurs when there is too much histamine. When your histamine levels increase, your tolerance decreases. At this point, histamine can cause a wide variety of symptoms, and these symptoms can vary depending on where it is released in the body.

Histamine Intolerance

Now that you have a general idea as to what histamine is and what role it plays in the body let’s talk about what histamine intolerance is. Histamine intolerance is thought to be due to a build-up of histamine in the body. When there is a build-up of histamine in the body, symptoms can occur.

In someone who does not have histamine intolerance, histamine is broken down within the body by the enzymes DAO and HNMT. With histamine intolerance, there could either be a genetic or a simple impairment in either or both of the enzymes responsible for the histamine breakdown leading to histamine build-up.

Causes of Histamine Intolerance

While it’s hard to pinpoint exactly what causes histamine intolerance, the impairment of DAO or HNMT is a major cause of this condition as is having impaired intestinal function. The enzyme DAO is produced in the intestine so any impairment to the intestine could result in a lack of the DAO enzyme impairing histamine breakdown.

This is a major reason why those who suffer from gastrointestinal conditions seem to suffer from histamine intolerance more often. The condition is commonly found in those who suffer from IBS, inflammatory bowel disease, celiac disease as well as SIBO.

Another cause could be due to certain medications that impair the DAO enzyme.

There are many other potential causes of histamine intolerance including:

  • Environmental causes such as pollen and dust mites
  • Excessive alcohol intake
  • A diet too high in fermented foods, too much protein, and consuming aged foods
  • Hormonal excess, particularly estrogen
  • Adrenal dysfunction
  • Lack of sleep
  • Stress & anxiety
  • Nutrient deficiencies
  • Gut infections & more

Symptoms of Histamine Intolerance

Some of the most common symptoms of histamine intolerance are as follows:

  • Headaches
  • Diarrhea
  • Eczema or hives
  • Irregular heartbeat
  • Low blood pressure
  • Wheezing
  • Runny nose
  • Heartburn
  • Premenstrual syndrome
  • Seasonal allergies
  • Food allergies
  • Asthma
  • Motion sickness
  • Nausea
  • Vomiting
  • Irritability
  • Loose stool
  • Chest tightness

Histamine intolerance commonly goes undiagnosed because many of the symptoms mimic an allergic reaction. However, the two aren’t the same.

Histamine intolerance is not mediated by IgE like a food allergy would be. This is why skin allergy testing is not an accurate way of diagnosing histamine intolerance; those tests would likely come out to be negative.

Symptoms associated with histamine intolerance are also not always immediate as they would be with a food allergy. Symptoms, however, can be triggered at any time when histamine has reached a certain level within the body. This is also why identifying certain foods as culprits can prove to be difficult.

How to Diagnose Histamine Intolerance

Histamine intolerance can be difficult to diagnose, but with the right practitioner, you could get to the bottom of the cause of your symptoms.

There is no true diagnostic test for histamine intolerance other than blood and urine screening to measure both histamine and DAO levels.

Related disorders such as allergies, mast cell disorders, and gastrointestinal conditions are also looked at while trying to diagnose this condition. Once other conditions are ruled out, a histamine elimination diet could be started to see if symptoms improve when histamine-rich foods are eliminated from the diet.

If symptoms improve, this could be a telltale sign that you may be suffering from histamine intolerance.

Treatment Options for Histamine Intolerance

While diet is an integral part of healing from histamine intolerance, there are other treatment options that come into play.

  • Low histamine diet: Avoid foods such as fermented or smoked meats, dried fruits, citrus fruit, legumes, gluten, cinnamon, chocolate, fermented milk products
  • Adequate sleep
  • A healthy exercise routine
  • Stress reductions
  • Medications in certain circumstances
  • Supplements such as quercetin
  • Environmental changes: Clean air ducts, air purifiers

Another natural option I recommend to patients is a supplement called histo-relief. This supplement supports immune function, as well as the body’s response to food and environmental factors, and aids in gastrointestinal function and antioxidant processes. I love this supplement because it’s made from natural compounds to naturally support the body.

It’s important to know that while treating histamine intolerance can be difficult with restrictive low-histamine diets, the condition does tend to improve once underlying conditions are addressed. Many of these conditions are related to digestive health, which is why it’s critical to work with a practitioner who has experience with this condition and someone who is going to take an integrative approach to treating the condition. All systems in the body need to be supported or histamine intolerance may not get any better.

If you are suffering from weight gain, fatigue, hair loss and more, click here to schedule a phone call with my team, so we can find out where you’ve been, where you want to get to, and how we can help you get there.

I know exactly where you are because I’ve been there myself…I remember being so tired that I could barely function. I gained 30 pounds out of nowhere and had a severe case of brain fog. I also started to get severe anxiety and panic attacks. I was driven and motivated…until I wasn’t. I didn’t know what was happening to me. All I wanted was to get my life back…

Finally, I learned about functional medicine and found a practitioner that I hoped could help me. They ran specialized tests that were far different than I had ever had before. When I got the results back, it turned out I had candida, parasites, high cortisol, the Epstein Bar Virus and many food intolerances. I also had an issue with my thyroid that no one found before because they were using the conventional medicine lab ranges which are way too broad….which I now know is one of the leading causes of hypothyroid misdiagnosis.

I went through treatment of all of these things and it completely changed my life.  I immediately lost the 30 pounds I had gained plus more, I had a lot more energy, and my brain fog was gone. I felt amazing and knew that I wanted to help people find the underlying causes of their symptoms and disease.


Amy Burkhart. Histamine Intolerance: Could it be causing your symptoms?

Dr. Lynch (2015) Histamine Intolerance, MTHFR and Methylation.




Hi, I am Dr. Becky Campbell. I work with men and women who’ve had a health set back and are willing to do whatever it takes to reach optimal health so they can perform their best in their careers and be fully present with their family again.