What is DAO deficiency

DAO deficiency is an alteration in the metabolism of food histamine that occurs when there is little activity of the enzyme diamine oxidase (DAO). The DAO is the main enzyme in the metabolism of exogenous histamine and begins its functional activity in the intestine.

When exists a disproportion between the histamine swallowed or released by the cells that store it in the body, and the ability to metabolize it, there is the accumulation of histamine in plasma and the appearance of adverse effects.

A deficit in the metabolic activity of diamine oxidase can be due to genetic, pharmacological and pathological factors.

main symptoms in DAO deficiency

Migraine, fibromyalgia, irritable bowel syndrome (IBS) and the attention deficit-hyperactivity disorder (ADHD) are the symptoms with higher prevalences in the world population caused by DAO deficiency.


millions of people affected by ADHD

% of the population with ADHD is also affected of DAO deficiency

millions of people affected by migraine

% of the population with migraine is also affected of DAO deficiency

millions people affected by fibromyalgia

% of the population with fibromyalgia is also affected of DAO deficiency

millions of people affected by Irritable Bowel Syndrome

% of the population with Irritable Bowel Syndrome is also affected of DAO deficiency

Actuality about DAO deficiency

News in media and press releases

Migraines seem to be caused most likely by histamine than by ethanol – Eur J Neurol

The past 20 May was published in the European Journal of Neurology an article in which the doctors Wolfgang J Schnedl and Robert Queissner stated that there was apparently a greater relationship between the cause of migraines and histamine rather than with ethanol present in alcoholic beverages. In the letter to the editor that have published both doctors, reflect on...

Clinical evidence and scientific publications 

Association of Diamine oxidase (DAO) variants with the risk for migraine from North Indian population

Association of Diamine oxidase (DAO) variants with the risk for migraine from North Indian population Dowload pdf Sukhvinder Kaura,⁎, Arif Alib, Yaser Siahbalaeic, Uzair Ahmadc, Fazila Nargisc, A.K. Pandeyd, Balkirat Singhe a UGC-PDF, Gene Expression Lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, India b UGC-BSR-FF, Department of Biosciences,...

Activities and events on DAO deficiency


Next Monday 17 June (2019), will take place from 14.00 to 16.00 hours in the University Rovira i Virgili (Edifici N5 Sustainable Chemistry, Assembly Hall.Marcel.li Sunday, 2-4-6, Sescelades Campus 43007-Tarragona, Spain) the training activity “DAO deficiency and the role of the pharmacist in the diagnosis and treatment” (language: Spanish). This training is organized...


Are underestimated the amounts of biogenic amines in diets low in histamine ?

  Diets low in histamine are currently used to reduce symptoms of intolerance to histamine, a disorder in the homeostasis of this molecule that increases its blood levels, due mainly to the reduction of the activity of the diamine oxidase (DAO) enzyme. In fact, these diets low in histamine exclude foods, many of them of plant origin, that patients associate with the...
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