Histamine intolerance means you have high histamine levels in your body. It can happen if your body cannot break down histamine. It can affect multiple systems in your body, but gastrointestinal symptoms are most common.

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

Histamine is a chemical responsible for a few major functions, including:

  • sending messages to your brain
  • triggering the release of stomach acid to help digestion
  • releasing after injury or allergic reaction as part of your immune response

When there’s too much histamine, or your body cannot break it down properly, it can affect typical bodily functions.

Because you have histamine receptors throughout your body, histamine intolerance can affect several body systems. In a small 2019 study, participants experienced an average of 11 symptoms, with 96.8% experiencing more than 3 symptoms.

Histamine intolerance symptoms are nonspecific. That means they can appear like symptoms of other conditions. This can often make it challenging for doctors to diagnose.

Gastrointestinal (GI) symptoms are the most common and include:

While they may vary, other common reactions associated with this intolerance include:

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

You naturally produce histamine along with the enzyme diamine oxidase (DAO). DAO is responsible for breaking down histamine that you take in from foods.

If you develop a DAO deficiency and cannot break down histamine, you could develop histamine intolerance.

Things that can affect your DAO enzyme or histamine levels include:

  • Genetics: You may have a gene mutation that causes your body to produce DAO.
  • Medications: Some medications can temporarily block DAO functions or prevent production, including:
  • Gastrointestinal (GI) disorders: GI disorders like inflammatory bowel disease (IBD) can cause DAO deficiency.
  • Diet: Histamine-rich foods can cause DAO enzymes to function improperly. Some foods can block DAO enzymes or trigger histamine release.
  • Bacterial overgrowth: When your body is unable to digest food properly, bacteria grow, causing you to produce too much histamine. Typical DAO enzyme levels cannot break down the increased histamine in your body, causing a reaction.

What diseases cause histamine intolerance?

Histamine intolerance usually stems from an intestinal issue. You may be more likely to develop histamine intolerance if you have a gastrointestinal disorder, such as:

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Foods to consider limiting

A health-promoting diet contains moderate levels of histamine. However, some foods high in histamine can trigger inflammatory reactions and other negative health events.

The benefits of a histamine-limiting diet are still an uncertain field of study. More research is needed. Limiting these foods may help some but not others.

Histamine-rich foods include:

Several foods can also trigger histamine release in your body, such as:

Drinks that block DAO production include:

In a systematic review from 2021, many of the foods typically listed as high-histamine or histamine-triggering may not actually have this effect depending on the person.

For instance, based on this systematic review, citrus fruits and fish were very low in histamine. Research results also showed that various studies focusing on a low-histamine diet really differed in their approach, and the list of foods to avoid or to consume was significantly different.

The best strategy may be to try eliminating foods you suspect that are adversely contributing to your health events to see if doing so helps or changes your symptoms.

Foods to eat

If you have histamine intolerance, incorporating low-histamine foods into your eating pattern can help reduce symptoms. There are several variations of low-histamine eating plans. It’s important that you consult a healthcare professional such as a dietician before you eliminate foods from your eating plan.

Some foods low in histamine include:

Other than making changes to your eating pattern, there’s not much you can do to fix histamine intolerance.

Antihistamines may help reduce symptoms in the short term.

A 2020 research review notes that DAO supplements may also help, but more research is needed to confirm how well they work.

Before reaching a diagnosis, a doctor will eliminate other possible disorders or allergies that cause similar symptoms.

They may also suggest following an elimination diet for 14–30 days. This diet requires you to remove foods high in histamine or histamine triggers before slowly reintroducing them to watch for new reactions.

A doctor might also request a blood sample to analyze whether you have a DAO deficiency.

Another way to diagnose histamine intolerance is through a prick test. A typical prick test checks for allergic reactions within 20 minutes. But a prick test for histamine intolerance will typically require a 50-minute wait to get results.

Histamine intolerance can cause uncomfortable symptoms, but a low-histamine eating plan may help ease symptoms.

Diagnosing histamine intolerance can be challenging as symptoms are similar to other allergens, disorders, or infections. During the diagnosis process, a doctor will need to eliminate similar medical conditions.

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