Where is DAO Naturally Found in the Body and in Foods?

November 26, 2025 •

4 min read

Approximately 80% of histamine intolerance cases are linked to a deficiency of the enzyme diamine oxidase (DAO), which is responsible for breaking down histamine. To manage symptoms, understanding where DAO is naturally found—both in the body and in certain foods—is critical for those with low levels of this enzyme.

Quick Summary

Diamine oxidase (DAO) is primarily produced by the intestinal lining and kidneys, but also occurs in specific food sources. Consuming foods like pea sprouts and pork kidney can provide exogenous DAO, while a nutrient-rich diet supports the body's own production.

Key Points

Endogenous Production: The body naturally produces DAO in the small intestine, kidneys, and placenta to regulate internal and ingested histamine levels.
Top Food Sources: The most potent food sources of DAO are raw legume sprouts (especially pea shoots) and pork kidney.
Supporting Nutrients: Key nutrients like Vitamin C, Vitamin B6, copper, and zinc are cofactors essential for the body's own DAO synthesis.
Gut Health is Crucial: A healthy intestinal lining is vital, as the small intestine is the primary site of DAO production. Inflammation can impair this process.
Careful with Supplements: While pork kidney is a source of DAO, some food sources can also be high in histamine, which may trigger reactions in sensitive individuals.
Avoid Inhibitors: Substances like alcohol, certain teas, and some medications can inhibit DAO activity, leading to higher histamine levels.

Your Body's Internal DAO Production

The most significant and constant source of diamine oxidase (DAO) is your own body. This enzyme is manufactured in various tissues to manage histamine levels, playing a critical role in digestion, immune response, and overall health. For most people, this endogenous production is sufficient to handle dietary histamine and maintain balance.

Key Sites of Endogenous DAO Production

Intestinal Mucosa: The primary site for DAO production is the lining of the small intestine. Here, DAO works to degrade histamine from food before it enters the bloodstream, acting as a critical metabolic barrier.
Kidneys: The kidneys also contain significant amounts of DAO, where the enzyme is involved in degrading histamine that has been reabsorbed or is circulating in the body.
Placenta: During pregnancy, the placenta dramatically increases DAO production (up to 1,000 times pre-pregnancy levels) to protect the fetus from potentially excessive histamine levels.
Thymus: This organ, which is vital for immune function, is another location where DAO is naturally found.

Exogenous DAO: Found in Foods

Beyond your own body's internal production, some foods contain measurable amounts of the DAO enzyme, which can be particularly beneficial for individuals with low DAO activity or histamine intolerance.

List of Foods with Exogenous DAO

Raw Legume Sprouts: The highest known plant-based source of exogenous DAO is raw legume sprouts, with pea shoots being exceptionally potent. Research suggests that sprouted peas can have more DAO activity than even porcine kidneys. Other sprouts like mung bean, lentil, and alfalfa also offer DAO activity.
Pork Kidney: A traditional source of DAO, pork kidney is often used in dietary supplements due to its naturally high DAO content. However, some sources suggest it can also be high in histamine, which may be a concern for highly sensitive individuals.

Supporting Your Body's DAO Production

For most individuals, boosting DAO naturally isn't about eating foods that contain the enzyme, but rather providing the necessary building blocks for the body to produce it efficiently. A balanced, nutrient-dense diet is key to supporting this process.

Essential Cofactors and Supporting Foods

Copper: DAO is a copper-dependent enzyme, so adequate copper intake is crucial. Foods like almonds, pumpkin seeds, and Swiss chard can provide copper.
Vitamin B6: This vitamin is a vital coenzyme in the pathways related to DAO production. Sources include salmon, poultry, sweet potatoes, and pistachios.
Vitamin C: Known for its natural antihistamine properties, Vitamin C also helps stabilize mast cells. Good sources include broccoli, Brussels sprouts, and parsley.
Zinc: Zinc is another mineral that supports DAO synthesis and promotes gut health. You can find it in chicken, pork, and pumpkin seeds.
Omega-3 and Oleic Acid: Some studies indicate that healthy fats, particularly omega-3s and oleic acid from sources like olive oil, can help increase DAO release.

The Crucial Role of Gut Health

Given that the intestinal lining is the primary production site for endogenous DAO, maintaining a healthy gut is paramount for optimal enzyme function. Chronic inflammation, infections, or intestinal damage can all impair DAO production.

Strategies for a Healthy Gut

Nourish the Microbiome: A high-fiber diet rich in prebiotics, from foods like onions, garlic, and asparagus, can support the growth of beneficial gut bacteria.
Avoid Inflammatory Triggers: Limiting processed foods, refined sugars, and substances that inhibit DAO (like alcohol, black tea, and green tea) can help reduce gut inflammation.
Consider Probiotics: Certain probiotic strains, such as Bifidobacterium, can support mucosal health and potentially improve DAO activity.

Comparison of DAO Sources

DAO can come from both internal and external sources. The following table compares the characteristics of endogenous (body-produced) DAO and exogenous (food-derived) DAO.


Feature	Endogenous DAO	Exogenous DAO
Source	Produced by the body, primarily in the intestines, kidneys, and placenta.	Consumed via food, with high concentrations found in specific items like legume sprouts and organ meats.
Activity	Continuous, systemic production that acts as a metabolic barrier for ingested histamine.	Offers temporary support for breaking down histamine from the specific meal it is consumed with.
Dependence	Relies on adequate nutrition, gut health, and genetics for proper function.	Its effectiveness is dependent on the quantity and activity of the enzyme in the specific food consumed.
Considerations	Internal factors like inflammation, stress, or genetic mutations can impair production.	Some food sources (e.g., pork kidney) can be high in histamine, requiring careful consumption for sensitive individuals.

Conclusion

Where DAO is naturally found depends on the type of source: internal or external. Your body produces DAO in key organs like the small intestine and kidneys to regulate histamine. Certain foods, particularly raw pea sprouts and pork kidney, are concentrated external sources of this enzyme. For optimal histamine management, a combination of supporting your body's internal production with essential nutrients and a healthy gut, while strategically incorporating exogenous food sources, offers the most comprehensive approach. A nutrient-rich, low-histamine diet can reduce the overall histamine load, thereby decreasing the pressure on your body's natural DAO resources. Individuals with histamine intolerance should always prioritize fresh foods and consider professional guidance for dietary changes. Creative Enzymes provides valuable insights into food-based strategies for DAO support.

Frequently Asked Questions

Yes, but there are two ways. You can eat foods that contain the DAO enzyme directly, such as raw pea shoots. More importantly, you can consume foods rich in cofactors like copper and vitamins B6 and C to support your body's own DAO production.

The primary natural source of DAO in the human body is the intestinal mucosa, or the lining of the small intestine. Significant amounts are also found in the kidneys and the placenta during pregnancy.

Yes, many commercially available DAO supplements are derived from natural sources, most commonly from porcine (pig) kidney extract or, more recently, from pea shoots.

Some foods that contain DAO, such as pork kidney, can also be high in histamine. For individuals with severe histamine intolerance, the histamine content in these foods may outweigh the benefit of the DAO enzyme.

Fermented foods, like sauerkraut and aged cheeses, are typically high in histamine and do not contain active DAO. The fermentation process itself does not create or preserve the enzyme; in fact, these foods put a burden on your body's DAO.

Optimal gut health is essential for DAO production because the intestinal lining is the main site of synthesis. Conditions like inflammation or gut infections can damage the intestinal barrier and significantly impair DAO synthesis.

Yes, the best-known and most potent vegetarian source of exogenous DAO is raw legume sprouts, particularly pea shoots. Lentil, mung bean, and alfalfa sprouts also contain measurable DAO activity.