Histamine intolerance is not a sensitivity to histamine, but an indication that you’ve developed too much of it.

Histamine is a chemical in your body responsible for a few major functions:

  • As a neurotransmitter, histamine communicates messages to your brain.
  • Histamine is a component of stomach acid that helps to break down your food in the digestive process.
  • Histamine is released after injury or allergic reaction as part of the body’s immune response.

When histamine levels get too high or when histamine cannot break down properly, it can affect your normal bodily functions.

Histamine is most associated with common allergic responses and symptoms. Many of these symptoms are similar to those exhibited from a histamine intolerance.

While they vary from one person to the next, some common reactions associated with this intolerance include:

In more severe cases of histamine intolerance, you may experience symptoms including:

Histamine is naturally produced in the body, along with the enzyme diamine oxidase (DAO). This enzyme is responsible for breaking down histamine ingested from foods. If you develop a DAO deficiency and are unable to break down histamine, you could develop an intolerance.

Some reasons your DAO enzyme levels could be affected include:

  • medications that block DAO functions or prevent production
  • gastrointestinal disorders, such as leaky gut syndrome and inflammatory bowel disease
  • histamine-rich foods that cause DAO enzymes to function improperly
  • foods that block DAO enzymes or trigger histamine release

Bacterial overgrowth is another contributing factor for developing a histamine intolerance. Bacteria grows when food is not digested properly, causing histamine overproduction. Normal levels of DAO enzymes can’t break down the increased levels of histamine in your body, causing a reaction.

Foods to avoid

A healthy diet contains moderate levels of histamine to support normal immune functions. However, there are some foods high in histamine that can trigger inflammatory reactions and other negative symptoms.

Histamine-rich foods are:

There are also a number of foods that trigger histamine release in the body or block DAO production. Histamine-release foods are:

DAO blockers are:

Foods to eat

If you have a histamine intolerance, incorporating low-histamine foods into your diet can help reduce symptoms. There is no such thing as a histamine-free diet. Consult with a dietician before you eliminate foods from your diet and establish a new histamine threshold.

Some foods low in histamine include:

Before you’re diagnosed with a histamine intolerance, your doctor will eliminate other possible disorders or allergies that cause similar symptoms.

Doctors may also suggest following an elimination diet for 14–30 days. This diet requires you to remove any foods high in histamine or histamine triggers, and slowly reintroduce them to watch for new reactions.

Your doctor might also take a blood sample to analyze whether you have a DAO deficiency.

Another way to diagnose histamine intolerance is through a prick test. A 2011 study examined the effectiveness of a prick test to diagnose histamine intolerance. Researchers pricked the skin of 156 people and applied a 1 percent histamine solution. The prick test was positive for 50 percent of the people, revealing a small wheal — or red, itchy bump — on the area of the skin tested.

Histamine intolerance can cause uncomfortable symptoms, but it can be treated with a low-histamine diet. Histamine intolerance should not be self-diagnosed because symptoms are similar to other allergens, disorders, or infections.

If you think you might have an intolerance or are experiencing irregular symptoms, talk to your doctor.