The digestive enzyme that metabolizes histamine
Diamine Oxidase (DAO)
The enzyme that metabolizes ingested histamine is diamine oxidase (DAO). It is produced by cells that line the small intestine. Inadequate amounts of the DAO enzyme can result in excessive histamine in the digestive tract causing the symptoms. This is a genetic problem.
I take 750 mg a day of vitamin B6, which is used by the intestinal cells to produce DAO. It has reduced my symptoms but has not eliminated them. This is well above the recommended daily amount of B6 but I cannot find any guidance as to an appropriate amount to treat DAO deficiency. The amount probably depends on the severity of the genetic inactivity. Some gene variants are totally inactive, while others may be partly active. I do not have a diagnosis as to which variant of the DAO gene I have.
A DAO enzyme supplement can be purchased. If taken just before eating high-histamine foods it should reduce the symptoms. I’ve had mixed success taking a DAO supplement (Histamine Block) each time my family gathers for turkey dinner, but that could be due to other mistakes made by the cook (I have so many dietary issues, I’m difficult to cook for. With IBS-D, it is often hard to identify the specific ingested thing that caused symptoms, especially as it often takes several days before symptoms become manifest.)
I have not made a habit of taking the DAO supplement daily, or before every meal, because it is still too novel a treatment to know if there are any long-term risks.
I take 750 mg a day of vitamin B6, which is used by the intestinal cells to produce DAO. It has reduced my symptoms but has not eliminated them. This is well above the recommended daily amount of B6 but I cannot find any guidance as to an appropriate amount to treat DAO deficiency. The amount probably depends on the severity of the genetic inactivity. Some gene variants are totally inactive, while others may be partly active. I do not have a diagnosis as to which variant of the DAO gene I have.
A DAO enzyme supplement can be purchased. If taken just before eating high-histamine foods it should reduce the symptoms. I’ve had mixed success taking a DAO supplement (Histamine Block) each time my family gathers for turkey dinner, but that could be due to other mistakes made by the cook (I have so many dietary issues, I’m difficult to cook for. With IBS-D, it is often hard to identify the specific ingested thing that caused symptoms, especially as it often takes several days before symptoms become manifest.)
I have not made a habit of taking the DAO supplement daily, or before every meal, because it is still too novel a treatment to know if there are any long-term risks.
