Does taking a Diamine Oxidase (DAO) enzyme before a meal help limit histamine release?

DAO Enzyme Supplementation for Histamine Management

Taking a DAO enzyme supplement before a meal does not effectively limit histamine release, but it may help break down ingested histamine in some individuals with histamine intolerance. 1

Understanding Histamine and DAO

Histamine intolerance results from an imbalance between accumulated histamine and the body's capacity to degrade it, primarily through the enzyme diamine oxidase (DAO). This enzyme is highly expressed in the gastrointestinal tract, where it helps control histamine intake from food 2.

Key points about histamine and DAO:

• Histamine is a biogenic amine found in various foods and is also produced endogenously
• DAO is the main enzyme responsible for metabolizing ingested histamine 2
• Histamine intolerance symptoms occur when there's an excess of histamine that cannot be adequately degraded

Efficacy of DAO Supplementation

Research on DAO supplementation shows mixed results:

• A 2018 double-blind, placebo-controlled study found that DAO supplementation (1 capsule twice daily, 15 minutes before meals) reduced symptoms in chronic spontaneous urticaria patients with low serum DAO levels 3
• A 2019 open-label interventional study reported significant improvement in histamine intolerance symptoms during 4 weeks of DAO supplementation before meals, with symptoms returning after discontinuation 4
• However, a 2020 study evaluating commercially available DAO supplements found that they did not contain sufficient enzyme activity to effectively degrade food-relevant amounts of histamine 5

Important Considerations

1. DAO breaks down ingested histamine, not released histamine:

   • DAO supplements target dietary histamine in the gut
   • They do not prevent mast cell degranulation or histamine release from cells 6
   • They cannot prevent histamine release triggered by allergens or other stimuli

2. Enzyme activity concerns:

   • Commercial DAO supplements may not contain sufficient enzyme activity for effective histamine degradation 5
   • The stability of DAO in digestive conditions is limited, with a half-life of around 19 minutes in simulated intestinal fluid 5

3. Individual response variation:

   • Benefits appear most significant in those with documented low DAO levels 3
   • Response to supplementation varies considerably between individuals 1

Alternative Management Approaches

For those with histamine-related symptoms, more established approaches include:

• Low-histamine diet: Avoiding fermented foods, aged cheeses, processed meats, and other high-histamine foods 1
• Antihistamine medications: Combined H1 and H2 antihistamine therapy is recommended for controlling histamine-related symptoms 1
  • Second-generation H1 antihistamines (cetirizine, fexofenadine, loratadine) are preferred due to less sedation 6

Conclusion

While DAO supplementation may help some individuals with histamine intolerance by breaking down ingested histamine, it does not prevent histamine release in the body. The most effective approach for managing histamine-related symptoms combines dietary management (low-histamine diet) with appropriate antihistamine medications when needed.

For those considering DAO supplementation, it's important to understand its limitations and to have realistic expectations about its potential benefits.