Diamine oxidase

Diamine oxidase (DAO), also known as histaminase, is an enzyme that breaks down histamine. The highest concentrations of DAO are found in the digestive tract and the placenta.

Supplementation
DAO is available in supplement form and is sometimes taken by individuals with mast cell activation disorder.

Magnesium is an important cofactor in the production of DAO and magnesium deficiency may result in decreased DAO activity and excess histamine levels.

Copper, Vitamin B6 and Vitamin C are other important DAO cofactors.

Heparin increases the activity of DAO in the blood.