Food-related migraine - DAO enzyme activity test
22/04/2026
What does the test involve?
The DAO enzyme activity test (DAO Test) is a diagnostic test used to measure the activity of the DAO enzyme (diamine oxidase) in the blood.
Some patients who suffer from migraine may find out whether the origin of their symptoms is related to a disorder in the metabolism of histamine, a substance present in certain histamine-rich foods.
The test measures DAO enzyme activity and expresses the results in HDV (Histamine Degrading Units).
A value below 80 HDV is considered moderate histamine intolerance, and a value below 40 is considered high histamine intolerance.
Histamine-DAO-Migraine relationship
Migraine is a complex, recurrent and disabling condition. Headache, often unilateral and pulsating, associated with photo- and phonophobia, nausea and vomiting, is the most frequent and characteristic clinical sign. For decades, numerous clinical, histochemical, molecular and genetic approaches have generated a wide range of hypotheses regarding the origin of migraine, but none has fully clarified its etiopathogenesis.
Most therapeutic approaches for the acute treatment of migraine include medications that interact with vascular receptors. Prophylaxis for this condition frequently includes agonists, as well as calcium channel blockers and beta-adrenergic receptor antagonists.
Histamine is a substance of great biological interest that is widely distributed throughout the different tissues of the human body, where it performs important physiological functions. It acts as a mediator in immediate hypersensitivity responses and allergies, plays a role in the function of smooth muscle in the bronchi and blood vessels, in the regulation of gastric secretion and as a neurotransmitter in the central nervous system, among others.
Histamine is also a biogenic amine that can be found in many everyday foods; in particular, it can be present in high amounts in foods that have often been identified as migraine triggers in susceptible individuals.
Role of DAO
Reduced metabolic capacity is the origin of what is known as histamine intolerance or food-related histaminosis, resulting from inadequate functioning of the histamine metabolism systems, mainly due to deficient DAO enzyme activity.
This enzyme deficiency may have three possible origins:
- Genetic origin: genetic polymorphisms with different enzyme activity have been identified, which explains why migraine may occur within the same family group.
- Pathological origin: DAO deficiency appears to be more prevalent among people with inflammatory bowel diseases (ulcerative colitis, Crohn’s disease, etc.).
- Pharmacological origin: due to the blocking or inhibition of DAO by various medications. This risk appears to be relatively significant, as around 90 medications, some of them very commonly used, have been reported as capable of inhibiting DAO.
Prevention of food-related migraine
When migraine is caused by histamine intolerance, certain dietary recommendations have been proposed, including reducing or eliminating alcohol consumption and excluding potentially triggering foods.
Histamine is present in most foods in varying amounts, making a complete exclusion diet impractical. However, it is useful to establish dietary guidelines and avoid histamine-rich foods that are consumed recurrently. Symptoms appear due to the accumulation of histamine. In general, processed foods such as cured meats, milk and dairy products, fermented soy products, industrial pastries, ready-made meals and fermented vegetables should be avoided. Alcoholic beverages act as DAO enzyme inhibitors and contain high levels of histamine.