New Study Finds DAO Deficiency Accounts for Over 70% Of All Histamine Intolerance
A study just published on 16 November 2015 has confirmed that DAO deficiency remains the leading cause of histamine intolerance.
The study was conducted using 14 patients from one Italian hospital clinic. The participants were selected from past patients whom had benefited from a low histamine diet.
Patients had a blood DAO test, and 10 of the 14 study participants, had on average less than one fifth of a healthy person’s DAO.
The study concluded that in patients with symptoms triggered by histamine-rich food, measuring the serum diamine oxidase activity, can help identify subjects who can benefit from a histamine limitation diet and/or diamine oxidase supplementation.
The study also demonstrates that DAO deficiency is the primary cause of intolerance to histamine-rich foods.
DAO (diamine oxidase) is the main enzyme involved in the break-down of histamine.
It is mostly concentrated in the small intestine where most food is ingested and food derived histamine is degraded.
DAO deficiency occurs where DAO in the small intestine is insufficient to metabolise ingested histamine in the diet. This means that histamine tolerance is lower in these individuals.
How DAO Deficiency Is Acquired
DAO deficiency can also be acquired through:
– Genetic DAO mutation (although the precise enzyme has yet to be identified).
– DAO inhibiting medications.
– Alcohol consumptions (which is a DAO inhibitor).
– A compromised gut lining; including NSAID intolerance, coeliac or gluten intolerance, bowel disease, or leaky gut.
– Vitamin b6, vitamin c, and copper deficiencies.
Other causes of histamine intolerance include other enzyme deficiencies, mast-cell activation, and mastocytosis.
Within my practice, the most common differential diagnosis for histamine intolerance includes SIBO, mineral deficiencies, and adrenal and hormone imbalances.