Histamine intolerance is a condition that affects a significant number of people (about 1% of the population). Yet, it often goes undiagnosed or misdiagnosed. Intolerance to histamine occurs when the body is unable to effectively break down and eliminate histamine, leading to a buildup of this compound in the body. A buildup of histamine may provoke symptoms like runny nose, asthma, hives, itchy skin, flushing, headache, and diarrhea in susceptible individuals. In this blog post, we will explore the causes, symptoms, and management strategies for histamine intolerance, providing you with a comprehensive understanding of this often misunderstood condition.

What Is Histamine?

Histamine is a vital compound. The body makes histamine from histidine (an essential amino acid), and then stores it in various tissues (e.g., intestine, pancreas, liver, lungs). In response to injury or exposure to a foreign antigen (e.g., pets, pollen, dust, food allergens), the body releases stored histamine to help protect itself. Histamine tells stomach cells to make stomach acid (which kills any pathogen we may have swallowed), dilates (opens) blood vessels to allow immune cells to enter circulation (so they can travel to the site of infection), and it helps our brain stay awake.

Histamine is also present in many foods, though some foods have more histamine than others. Additionally, many foods have the capacity to release histamine directly from tissue mast cells, even if they themselves contain only small amounts of histamine. Both histamine-rich foods and foods that trigger histamine release contribute to the total body burden of histamine.

What Causes Histamine Intolerance?

According to the 2007 article Histamine and histamine intolerance, “histamine intolerance results from a disequilibrium of accumulated histamine and the capacity for histamine degradation.” In other words, histamine intolerance is when your body is unable to break down and get rid of all the histamine it’s exposed to — be it from food or endogenous production.

As a reminder, histamine enters the body via the food you eat. Your body can also create histamine when you are exposed to allergens and suffer allergic reactions.

So, if we are regularly exposed to histamine, how does the body get rid of it?

A Dull Diamine Oxidase (DAO)

Diamine oxidase (DAO) is the main enzyme responsible for breaking down histamine in the gut (i.e., histamine that enters the body via food). Healthy people have robust and effective levels of diamine oxidase (DAO).

Unfortunately, some individuals have a reduced capacity to break down histamine due to DAO deficiency. People with histamine intolerance either do not make enough of the DAO enzyme, or they have DAO enzymes that are too slow or inefficient. When DAO is impaired, histamine levels can rise. And the rise in histamine produces symptoms. As affirmed by the 2007 article, “the main cause of histamine intolerance is an impaired enzymatic histamine degradation caused by genetic or acquired impairment of the enzymatic function of DAO.”

Enzymes are like scissors. You want them to be like sharp, kitchen shears — able to cut quckly and efficiently. When enzymes are too slow or inefficient, it’s like trying to spatchcock a chicken with dull, kid-friendly scissors.

Medications, Gastrointestinal Disorders, and Certain Foods

In addition to DAO enzyme deficiency, other factors can contribute to histamine intolerance. These include certain medications (e.g., non-steroidal anti-inflammatory drugs, antidepressants), gastrointestinal disorders (e.g., leaky gut syndrome, small intestinal bacterial overgrowth), and intake of histamine-rich foods or foods that trigger histamine release within the body.

Histamine Intolerance Symptoms

The symptoms of histamine intolerance can vary widely among individuals. And they can be mistaken for other conditions (such as food allergy or digestive disorders), making diagnosis challenging. Some common symptoms include the following.

• Digestive issues such as abdominal pain, bloating, diarrhea, constipation, and acid reflux.
• Skin manifestations like hives, rashes, itching, and eczema.
• Respiratory issues including nasal congestion, sneezing, runny nose, and asthma-like symptoms.
• Headaches and migraines. Yes, histamine can trigger headaches, including migraines, in susceptible individuals.
• Fatigue and brain fog. Some people with histamine intolerance experience fatigue, difficulty concentrating, and memory problems.

If you experience any of the above symptoms. And those symptoms get worse during the spring or when eating certain foods. You may have histamine intolerance.

Managing Histamine Intolerance

While there is no cure for histamine intolerance, two main strategies can help manage the condition effectively. The first strategy is to support the DAO enzymes you have. The second general strategy is to reduce the amount of histamine in your body. Let’s take a deep dive into each approach. Keep in mind, these two approaches can be combined for the biggest therapeutic effect.

Support Your DAO

There several many ways to support your DAO enzymes.

1. Add more DAO

Consider taking a DAO enzyme supplement. HistaGest‑DAO by Designs for Health is a great option. Taking DAO enzymes can help support the breakdown of histamine in the gut. Taking these supplements before meals can aid in reducing the impact of dietary histamine.

2. Support the DAO you have

Another option is to supplement with DAO cofactors: vitamin C, vitamin B6, and copper. When your DAO enzymes have all the cofactors, they work better to degrade histamine. Note: vitamin C also has the ability to deactivate histamine.

Reduce Histamine Load

You can also support your DAO enzymes by reducing your body’s histamine load. In other words, by giving your enzymes less work to do (i.e., the less histamine present, the less histamine needs degraded).

Good news! There are several ways to reduce histamine load.

Big picture, the two basic ways are to (1) avoid consumption of histamine foods and (2) to reduce allergic response (i.e., mast cell degranulation) in your body.

3. Follow A Low-Histamine Diet

Histamine is present in many foods, though some foods have more histamine than others. Aged and fermented foods contain large amounts of histidine (an essential amino acid). Since histamine is made from histidine, many products of microbial fermentation contain histamine, including aged cheese, yogurt, sauerkraut, and wine. Additionally, many fruits and vegetables have the capacity to release histamine directly from tissue mast cells, even if they themselves contain only small amounts of histamine.

Consider using a diet diary (let me know if you’d like an example or instructions) to identify, and then avoid, foods that contribute to histamine load in your body. This may involve avoiding aged or fermented foods, processed meats, alcohol, and certain fruits and vegetables. Working one-on-one with a histamine-literate registered dietitian can help you craft a personalized anti-histamine eating plan.

What to eat on a low histamine diet

• Fresh meat (cooled or frozen) – including beef, pork, chicken
• Fresh fish (cooled or frozen) – including trout
• Eggs
• Fresh fruits – with the exception of plantains, most fresh fruits are considered to have a low histamine level
• Fresh vegetables – with the exception of tomatoes, eggplant and spinach
• Most leafy herbs
• Grains – and their products like bread, pasta, crackers, etc.
• Fresh pasteurized milk – and milk products like cream cheese, mozzarella, butter
• Most cooking oils
• Herbal teas (not caffeinated)

4. Calm Your Immune System

Mast cell degranulation is the main cause of endogenous (made by the body) histamine load. We need mast cells to help us fight infection. However, sometimes this immune response is inappropriate and too much — as is the case for food and season allergies. Learn more about food allergies here.

To help calm your immune system, consider taking supplements know to reduce the allergic response (e.g., mast cell degranulation) in your body. A great option is Natural D-Hist by Ortho Molecular Products, which contains the following key ingredients:

• Quercetin — known for its ability to stabilize mast cells and diminishing the release of histamine
• Bromelain — which enhances quercetin absorption and has been shown to reduce protein complexes associated with immune hypersensitivity
• Stinging nettle leaf — which controls mast-cell degranulation and histamine action
• Vitamin C –which deactivates histamine
• N-Acetyl Cysteine (NAC) — a precursor to glutathione (one of the most important antioxidants in the body). Both glutathione and NAC help to break up mucus allowing for clearing of the airways and improved respiratory health. 

5. Anti-Histamines

If you prefer a pharmaceutical approach, taking anti-histamine drugs can also reduce symptoms of histamine intolerance. The name (anti-histamine) suggests that these meds block the release of histamine in the body. On the contrary, these drugs do not block histamine release (or build-up) in the body. Instead, anti-histamines block histamine receptors — which trigger the immune response. Imagine histamine as a soldier brining an “alert” message. But the histamine receptor as the sergeant who commands everyone to jump into action to fight the invader. In other words, anti-histamines do not prevent the build-up of histamine in your body, they just prevent you from feeling the symptoms of that build-up.

Identify and Fix the Root Cause

Maintaining a healthy gut microbiome is essential for histamine degradation. Various gastrointestinal conditions (including food allergy, gluten sensitivity, Crohn’s disease, ulcerative colitis) are associated with “dull” DAO enzymes. Healing the gut and correcting microbial imbalances (dysbiosis) can help improve GI histamine degradation.

Stress can worsen histamine intolerance symptoms. Engaging in stress-reducing activities such as yoga, meditation, and exercise can help manage symptoms.

Conclusion

Histamine intolerance is a condition that affects many individuals and often goes undiagnosed or misdiagnosed. Understanding the causes, recognizing the symptoms, and implementing appropriate management strategies are crucial steps toward effectively managing this condition. If you suspect you may have histamine intolerance, consulting with a healthcare professional or a registered dietitian can help provide a proper diagnosis and develop a personalized plan for symptom management.

References

1. Maintz L, Novak N. Histamine and histamine intolerance. The American journal of clinical nutrition. 2007;85(5):1185-96.
2. Designs for Health. HistaGest‑DAO. Accessed at https://www.designsforhealth.com/products/histagest-dao.
3. Ortho Molecular Products. Natural D-Hist. Accessed at https://www.orthomolecularproducts.com/product/natural-d-hist.
4. The Root Cause Medicine Podcast #38: Are Your Symptoms Due To Histamine Intolerance with Dr. Becky Campbell