What Foods Are High in Diamine Oxidase? Understanding DAO and Your Diet

October 15, 2025 •

4 min read

Over 1% of the population is estimated to suffer from histamine intolerance, a condition often linked to low levels of the enzyme diamine oxidase (DAO). Understanding what foods are high in diamine oxidase and which support or inhibit its activity is crucial for managing symptoms effectively through diet and lifestyle changes.

Quick Summary

This guide separates fact from fiction about diamine oxidase (DAO), explaining which specific foods naturally contain the enzyme and which nutrients support its production in the body. It also details foods high in histamine or that inhibit DAO, offering a clear dietary strategy for managing histamine levels.

Key Points

DAO Enzyme Sources: Raw legume sprouts (like pea, lentil, and mung bean sprouts) and pork kidneys are among the only foods with measurable active DAO.
Endogenous DAO Support: Support your body's own DAO production by consuming foods rich in cofactors like Vitamin B6, C, copper, and zinc.
High-Histamine Foods: Avoid aged, fermented, and cured products, which are typically high in histamine and overload the DAO enzyme.
DAO Inhibitors: Limit or avoid alcohol, black tea, green tea, and energy drinks, as they can block DAO activity.
Freshness is Key: Histamine levels increase in food over time; prioritize fresh, unprocessed meals to reduce histamine load.
Cooking Method Matters: Opt for simple cooking methods like boiling or poaching, as high-heat methods can increase histamine content in foods.
Histamine Sensitivity is Individual: Use a food diary to identify personal histamine triggers and tolerance levels, as responses vary greatly.

Understanding Diamine Oxidase (DAO)

Diamine oxidase (DAO) is a crucial digestive enzyme that plays a vital role in metabolizing histamine in your body. Histamine is a compound involved in immune response, nervous system communication, and digestive function. While the body produces its own histamine, we also consume it through food. For individuals with histamine intolerance, a deficiency in the DAO enzyme can cause histamine to accumulate, leading to a variety of allergy-like symptoms such as headaches, hives, digestive issues, and nasal congestion.

The Role of DAO in Histamine Metabolism

DAO works by breaking down excess histamine in the small intestine, preventing it from entering the bloodstream and causing a systemic reaction. It's important to understand that managing histamine levels through diet involves two primary strategies: consuming foods that naturally contain or support DAO production, and avoiding foods that are high in histamine or that inhibit DAO activity.

Foods Naturally High in Diamine Oxidase (Exogenous DAO)

It's a common misconception that many everyday foods contain high levels of active DAO. In reality, the list of natural dietary sources for this specific enzyme is quite short. The DAO found in food is highly sensitive and can be destroyed by heat during cooking and pasteurization. For this reason, consuming these foods raw or lightly cooked is essential to preserve their enzyme activity.

Specific Sources of Exogenous DAO

Raw legume sprouts: Recent studies have identified certain raw legume sprouts as significant plant-based sources of DAO activity. Examples include:
- Pea shoots
- Lentil sprouts
- Mung bean sprouts
- Alfalfa sprouts
Pork kidney: As a traditional source of DAO, pork kidney is available from butchers or specialty markets.

To maximize the DAO activity from sprouts, researchers have found that germinating seeds in darkness for 6 to 8 days can increase the enzyme capacity significantly. However, high-heat cooking methods should be avoided as they rapidly degrade the enzyme.

Foods that Support Endogenous DAO Production

Since relying solely on exogenous DAO from food is challenging, a more practical dietary approach is to consume foods rich in the vitamins and minerals that act as cofactors for your body's own DAO production.

Key Nutrients for DAO Function

Vitamin B6 (Pyridoxine): A critical cofactor for DAO synthesis.
- Food Sources: Tuna, salmon, poultry, chickpeas, bananas, potatoes, fortified cereals.
Vitamin C: Helps stabilize mast cells that release histamine and may enhance DAO function.
- Food Sources: Broccoli, bell peppers, citrus fruits (if tolerated), strawberries (if tolerated).
Copper: An essential component of DAO's enzymatic structure.
- Food Sources: Organ meats (like liver), nuts, seeds, shellfish, whole grains.
Zinc: Supports DAO synthesis and overall immune function.
- Food Sources: Grass-fed meat, lentils, nuts, seeds.

Foods that Inhibit DAO or are High in Histamine

For individuals with histamine intolerance, managing symptoms is as much about avoiding trigger foods as it is about consuming supportive ones. Certain foods are naturally high in histamine or contain compounds that interfere with DAO activity.

High-Histamine Foods to Limit or Avoid

These foods typically undergo aging, fermentation, or curing, processes that increase their histamine content over time.

Fermented products: Sauerkraut, kimchi, pickles, kombucha, and yogurt.
Aged cheeses: Parmesan, cheddar, Gouda, and Camembert.
Cured and processed meats: Salami, ham, and bacon.
Certain fish: Mackerel, tuna, sardines, and anchovies.
Leftovers: Histamine levels increase the longer food is stored, especially meat and fish.

Foods and Substances that Inhibit DAO

Alcohol: All forms of alcohol, especially red wine and beer, block DAO activity and can increase histamine release.
Certain teas: Black tea, green tea, and mate tea can interfere with DAO enzymes.
Energy drinks: Often contain ingredients that can inhibit DAO.

A Practical Guide to DAO-Friendly Eating

Creating a diet that supports DAO function and manages histamine load requires careful planning. The best approach is to focus on fresh, unprocessed foods while minimizing intake of aged and fermented products.

Comparison of Food Choices


Food Category	DAO-Friendly (Low Histamine/Supportive)	High Histamine / DAO-Inhibiting
Protein	Freshly cooked meat (poultry, beef), cooked eggs, fresh or quick-frozen fish (trout, cod)	Processed, cured, or leftover meats (salami, bacon), aged fish (canned tuna, smoked salmon), shellfish
Dairy	Fresh pasteurized milk, cream cheese, ricotta, mozzarella, butter	Aged cheeses (cheddar, parmesan, blue), yogurt, kefir, buttermilk
Vegetables	Most fresh vegetables, including broccoli, carrots, cauliflower, cucumber, leafy greens (except spinach)	Tomatoes, eggplant, spinach, avocados, fermented vegetables (sauerkraut)
Fruits	Apples, pears, mangoes, melons, berries (if tolerated)	Citrus fruits, strawberries, pineapple, papaya, bananas, dried fruits
Grains	Rice, quinoa, oats, millet, yeast-free breads	Wheat-based products (for some), yeast extract, aged baked goods
Drinks	Water, herbal tea (excluding black/green), fresh fruit/vegetable juices (from low-histamine sources)	Alcohol (especially red wine and beer), black/green tea, energy drinks

Tips for a DAO-Supportive Diet

Prioritize Freshness: Always opt for the freshest ingredients possible. Histamine levels rise as food ages, so avoid leftovers, or consume them within a minimal time frame.
Cook Simply: Boiling or poaching can help preserve nutrients and minimize histamine increases, while frying and grilling can elevate histamine levels.
Monitor Your Triggers: Histamine sensitivity is individual. A food diary can help you identify your personal histamine threshold and specific triggers.
Support Gut Health: A healthy gut lining is where most DAO is produced. Incorporating gut-friendly foods and addressing underlying conditions can improve natural DAO synthesis.

Conclusion

While very few foods naturally contain active diamine oxidase, a targeted diet can significantly support your body's natural histamine management. Focusing on foods rich in DAO cofactors (vitamins B6 and C, copper, zinc), incorporating fresh legume sprouts, and minimizing high-histamine and DAO-inhibiting foods are key strategies. By understanding and implementing a DAO-supportive nutritional plan, individuals with histamine intolerance can effectively manage their symptoms and improve their overall digestive and immune health.

For more in-depth information, you can explore resources such as this article on enhancing DAO activity naturally: Boost Your Diamine Oxidase Levels: Natural and Supplemental Approaches.

Frequently Asked Questions

Diamine oxidase (DAO) is a crucial digestive enzyme produced by the body, mainly in the kidneys and gut, responsible for breaking down excess histamine and preventing it from building up.

It is difficult to get a significant amount of active DAO from food, as the enzyme is sensitive to heat and can be degraded during digestion. The more effective strategy is to consume foods that support your body's natural DAO production.

Raw legume sprouts (such as pea, lentil, and mung bean sprouts) and pork kidneys are the most notable dietary sources of active DAO.

No, high-histamine foods like aged cheese and fermented products do not contain DAO. Instead, they increase the histamine load in your body, which your own DAO enzyme must then process.

Alcohol, black tea, green tea, mate tea, and energy drinks are known to block or interfere with the activity of the DAO enzyme.

The body needs cofactors like Vitamin C, Vitamin B6, Copper, and Zinc to synthesize and activate DAO. Consuming a diet rich in these nutrients helps support endogenous DAO production.

Histamine levels increase in food over time, so prioritizing fresh food reduces the histamine load and minimizes the burden on your DAO enzyme.

There is no definitive test for histamine intolerance. It is often managed through a medically supervised elimination and reintroduction diet to identify individual triggers.