Diamine Oxidase (DAO) Supplements: The Link Between Histamine and Gut Health

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Diamine oxidase (DAO) is an enzyme that plays a critical role in regulating histamine levels in your body. Elevated histamine can trigger symptoms like allergies and digestive issues. While our bodies naturally produce DAO, some people may find that a supplement can offer extra support in maintaining histamine balance. Be sure to check out our article on Histamine Intolerance for more.

This article explores the science-backed benefits of Diamine Oxidase (DAO) supplements to help you understand their role in managing histamine-related conditions. And if Diamine Oxidase supplements are right for you,

What Is Diamine Oxidase?

Diamine oxidase (DAO) is an enzyme produced naturally in our bodies, with a high concentration in the lining of the digestive tract. This enzyme plays a crucial role in breaking down histamine. Histamine has many functions in the body. Not only does histamine contribute to immune response, but it also helps in digestion and has a role in various other biological processes. DAO acts as a check on histamine by breaking it down, helping to keep its levels within a balanced range.

In supplement form, DAO offers extra support for those who may have lower natural levels of this enzyme. This can be particularly useful for people who experience symptoms tied to elevated histamine levels, such as allergies or digestive issues. For example, if you’re someone who struggles with seasonal allergies or certain food intolerances, a DAO supplement might help alleviate some of those symptoms by aiding in the breakdown of excess histamine. In recent times, DAO supplements have gained attention as a method to manage histamine-related conditions, providing another tool in the toolbox for those seeking symptom relief.

Histamine and the diamine oxidase (DAO) enzyme have a direct relationship in the body, particularly when it comes to regulating histamine levels. Histamine is a compound involved in immune response, digestion, and even neurotransmission. It’s a critical substance, but high levels of histamine can lead to uncomfortable or even harmful symptoms like allergies, headaches, and digestive issues.

This is where DAO comes into play. DAO is found mainly in the digestive tract and serves as a natural regulator of histamine. It breaks down excess histamine to maintain a balanced state within the body. In essence, DAO acts as a gatekeeper, ensuring that histamine levels do not rise to a point where they become problematic.

If a person has lower levels of DAO, it could result in an inability to efficiently break down histamine, leading to the various symptoms associated with histamine imbalance. For this reason, DAO supplements have gained attention as a way to support the body’s natural ability to regulate histamine levels.

Who Would Be Likely To Benefit From DAO Enzymes?

People with symptoms of histamine intolerance might benefit from DAO enzyme supplements. These symptoms often become more noticeable after consuming foods that are high in histamine or that trigger the release of histamine. Foods that raise histamine levels include aged cheeses, fermented foods like sauerkraut and kimchi, alcohol, processed meats, canned fish, and avocados.

DAO enzyme supplements can help break down excess histamine, possibly improving the symptoms. Histamine intolerance symptoms can vary widely but often include:

  • Allergic Reactions: Such as itching, hives, or a runny nose
  • Digestive Issues: Including bloating, gas, and diarrhea
  • Headaches or Migraines: Particularly those that seem to occur after consuming histamine-rich foods
  • Respiratory Problems: Such as asthma or difficulty breathing
  • Skin Conditions: Like eczema or hives
  • Mood Fluctuations: Anxiety or irritability without a clear reason
  • Sleep Disturbances: Difficulty falling asleep or staying asleep
  • Irregular Heartbeat: Sometimes associated with high histamine levels
  • Fatigue or Tiredness: Especially after eating histamine-rich foods

People with chronic symptoms that seem to align with histamine intolerance may find relief by supplementing with DAO enzymes.

What Are the Benefits of Diamine Oxidase Supplements For Reduced Histamine?

  • Allergy Relief: DAO supplements can help break down excess histamine, which may reduce allergy symptoms like sneezing, itching and runny nose. [PMC8240126]
  • Improved Digestion: Some people with digestive issues linked to high histamine levels find relief by taking DAO supplements, which aid in breaking down histamine in the gut. [PMC6859183, PMC8069563]
  • Headache and Migraine Alleviation: Elevated histamine levels can trigger headaches or migraines in some people. DAO supplements may mitigate these symptoms by regulating histamine. [PMID: 29475774]
  • Skin Conditions: DAO supplements can help manage skin conditions like hives or eczema that may be exacerbated by high histamine levels. [PMID: 29698966],
  • Mood Regulation: Although not well-studied, some users report an improvement in mood and a reduction in anxiety symptoms when taking DAO supplements, possibly due to histamine’s role in neurotransmission. In one study, researchers found, “over 80% of patients exhibited prolonged food intolerance with elevated levels of serum histamine, leading to hyperpermeability of the blood-brain barrier, which has previously been implicated in the pathogenesis of major depressive disorder.” [PMC6620418]
  • Reduced Gastrointestinal Issues: Conditions like Irritable Bowel Syndrome (IBS) can sometimes be linked to high histamine levels, and DAO supplements may help manage these symptoms by breaking down excess histamine. [PMC8069563]
  • Enhanced Respiratory Function: By controlling histamine, DAO supplements may assist in reducing asthma symptoms or other respiratory issues related to inflammation. [PMC6480561, PMC5806734]
  • Lessened Food Sensitivities: DAO supplements can help break down histamine in foods, making it easier for people with food sensitivities to tolerate certain foods that would otherwise trigger a reaction. [PMC6859183]
  • Support During Pregnancy: Some pregnant women experience elevated histamine levels which can lead to complications; DAO supplements might help in managing these levels, although consult your healthcare provider for guidance. [PMID: 18499706]
  • Decreased Fatigue: DAO supplements may help in reducing fatigue symptoms that come from the body’s struggle to manage elevated histamine levels.
  • Reduced Fibromyalgia Symptoms: A study found that DAO supplementation in women with fibromyalgia was associated with greater improvements in pain and symptoms like fatigue, anxiety, and depression compared to the control group. [PMC10607251]
  • Possible Role in ADHD: Links with ADHD have been theorized. [PMC10455974, PMC7388140]
  • Possible Role in Improved Sleep: Histamine plays a role in wakefulness, so regulating its levels with DAO supplements may help improve sleep quality. [PMC8469513]

Are DAO (Diamine Oxidase) Supplements Safe?

Diamine oxidase (DAO) is generally considered safe, especially since it’s an enzyme that our bodies naturally produce. The main goal of taking DAO supplements is to help regulate histamine levels, aiming to alleviate symptoms like allergies or digestive issues. While side effects are rare, some people might experience mild digestive discomfort. But for the most part, this supplement has been well-tolerated in studies. Still, like any supplement, it’s important to be aware of possible interactions with medications or other supplements you might be taking.

Medication Interactions with Diamine Oxidase

  • Antihistamines: Taking DAO with antihistamines could lead to overly reduced histamine levels, affecting its effectiveness or causing other imbalances.
  • Antacids: Some antacids can affect stomach acidity, which may in turn impact how well DAO is absorbed or functions in the body.
  • Blood Pressure Medications: Since DAO helps regulate histamine, which can affect blood vessels, combining it with blood pressure medications could cause unpredictable changes in blood pressure levels.
  • Immunosuppressants: DAO has a role in immune function through histamine regulation. Taking it with immunosuppressive drugs might cause interactions that alter immune response.
  • Alcohol: Alcohol can inhibit DAO activity, so combining it with DAO supplements may reduce the effectiveness of the supplement.

Supplement Interactions with Diamine Oxidase

  • Quercetin: This supplement is often used for its antihistamine effect. Combining it with DAO could amplify histamine-lowering effects, possibly leading to an imbalance.
  • Vitamin C: This vitamin also has antihistamine properties. Taking it with DAO might lead to overly reduced histamine levels.
  • Zinc: Zinc is known to support immune function. Since DAO also plays a role in immune response, combining the two could lead to unpredictable effects on immune regulation.
  • St. John’s Wort: This herbal supplement can affect various enzymes and may interact with DAO, potentially reducing its effectiveness.
  • Probiotics: Some strains of probiotics can influence histamine levels in the gut. Combining them with DAO may result in unexpected interactions in histamine regulation.

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DAO Enzyme

The DAO (diamine oxidase) enzyme functions as the primary defense against histamine by breaking it down while it is still within the gut. By breaking down dietary histamine, DAO prevents extra histamine from being absorbed into the bloodstream and causing more symptoms system-wide. See The Full Article

Histamine Digest™ by Seeking Health

Histamine Digest™ by Seeking Health contains a patented enzyme formula providing 10,000 HDU of diamine oxidase (DAO) – the main enzyme responsible for the degradation of ingested histamine – per capsule. Histamine Block does not manage or address antibody-related or IgE-related food allergies.*

Suggested Use:
Take 1 capsule no more than 15 minutes before the consumption of histamine-rich foods, or take as directed by your healthcare professional.

Amount Per 1 Capsule Serving
Vitamin C … 10mg (as ascorbyl palmitate)
DAO2™ porcine kidney extract … 4.2mg (Diamine Oxidase Activity 10,000 HDU)


Food First!

Although this article discusses supplements in detail, don’t forget that we are absolutely committed to the “Food First” approach to nutrition. When it comes to your health, the totality of your eating habits far surpasses the impact of individual nutrients or any single supplement you consume. Even though this article doesn’t delve into the broader picture of your overall diet, it’s crucial to keep this element at the forefront of our minds. Your food needs to provide all the vitamins, minerals, fiber, and phytochemicals to nourish your body systems down to the cellular level.

Food choices, rather than supplements, are the most critical factors for a healthy gut microbiome. These trillions of tiny inhabitants in your gut affect your brain waves; they orchestrate your immune system. They possess the power to create molecules that can switch genes on or off and are even capable of synthesizing neurotransmitters. Opting for organic foods and steering clear of plastic packaging (including those labeled BPA-free) is a smart move to limit toxin exposure. The sum of all these parts leads to a powerful conclusion: the ultimate key to your health lies in the quality and balance of the food you consume. Supplements are secondary.

To Sum It Up

Diamine Oxidase supplements offer a range of health benefits that make them worth considering. From regulating histamine levels and improving digestive health to managing skin conditions and supporting immune function, these supplements have multiple advantages. While they are generally safe to use, it’s important to be aware of possible interactions with medications and other supplements. All things considered, Diamine Oxidase stands as an intriguing option for managing histamine-related issues. Again, be sure to check out our article on Histamine Intolerance for more.


This Article is Not a Substitute for Medical Advice

Dietary supplements are not designed to diagnose, treat, cure, or prevent any disease. The Supplement Sciences website seeks to provide comprehensive access to the most relevant supplement information along with convenient online ordering. We do not provide medical advice and cannot guarantee that every product suggested is completely without risk. Since each person is unique in their health history and medication use, it is important to discuss supplements with your personal physician. Specifically, pregnant women and individuals being treated for cancer or liver or kidney problems must consult their physician about every nutritional supplement they plan to take. People taking medications for the treatment of HIV or with a history of organ transplant must not take supplements without consulting with their physician.


About the Author

Stephanie Figon, MS, RDN, LD

Founder of NutriScape.NET. As a dietitian since 1992, Steph Figon has had experiences in consulting, 15 years in clinical, and has operated a private practice nutrition counseling office for since 2011. Connect on Linkedin

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