From the Research
The most effective treatment for low Diamine Oxidase (DAO) enzyme activity is adopting a low-histamine diet and supplementing with DAO enzyme, as evidenced by a 2019 study 1 that showed significant improvement in symptoms with DAO oral supplements.
Treatment Options
Treatment options for low DAO enzyme activity include:
- Dietary modifications: avoiding histamine-rich foods such as aged cheeses, fermented foods, cured meats, certain fish, alcohol, and some fruits and vegetables like tomatoes, spinach, and avocados
- DAO enzyme supplements: typically 10,000-20,000 HDU per meal, taken 15-30 minutes before consuming histamine-containing foods
- Supporting nutrients: vitamin B6 (50-100mg daily), vitamin C (500-1000mg daily), copper, and magnesium
- Antihistamines: like loratadine or cetirizine, which may provide symptomatic relief but don't address the underlying enzyme deficiency
- Mast cell stabilizers: such as quercetin (500-1000mg twice daily) or butterbur, which can complement treatment by reducing histamine release
Rationale
The primary treatment approach is based on the most recent and highest quality study available, which demonstrated the efficacy of DAO supplementation in improving symptoms in patients with histamine intolerance 1. While other studies have investigated the role of DAO in histamine intolerance, such as the 2023 study on the evaluation of serum DAO as a diagnostic test for histamine intolerance 2 and the 2023 study on the use of DAO as a marker for histamine intolerance 3, the 2019 study provides the most direct evidence for the effectiveness of DAO supplementation.
Key Considerations
- A low-histamine diet should be followed for 2-4 weeks initially to assess improvement before gradually reintroducing foods
- DAO enzyme supplements can be taken 15-30 minutes before consuming histamine-containing foods to help break down dietary histamine
- Supporting nutrients and mast cell stabilizers can complement treatment by reducing histamine release and supporting the body's natural histamine processing pathways.