Diamine oxidase (DAO) is the main enzyme responsible for breaking down histamine from food before it enters the bloodstream. When DAO activity is low, histamine can build up and trigger uncomfortable symptoms in sensitive individuals. Supplementing with DAO has been studied as a way to support histamine balance and improve quality of life.
- DAO levels are lower in people with histamine intolerance. Multiple studies show that patients with histamine intolerance consistently have reduced DAO enzyme activity compared to healthy controls. [1]
- Supplemental DAO can reduce histamine-related symptoms. In clinical trials, DAO supplementation has been shown to decrease common histamine-related issues such as digestive upset, headaches, skin flushing, and nasal congestion. [2]
- DAO may improve meal tolerance and overall wellbeing. A 2020 open-label study found that people taking DAO reported significant improvements in food-related quality-of-life scores, especially in the digestive and skin symptom categories. [3]