Dr. Pedro Ojeda, Coodirector of Ojeda’s Clinic of Asthma and Allergy, and member of the International Society of DAO deficiency, tells us about the nature of DAO deficiency, the symptoms of this metabolic disorder, the role of histamine in the body and the treatments available today for its management and prevention.
Dr. Pedro Ojeda begins by standin out that “the DAO deficiency is basically an enzyme problem, that is to say, it is a situation in which we lack the appropriate levels of the enzyme diamine oxidase which is an enzyme that is very important in the degradation of histamine, wherewith we accumulate histamine in the body, in the tissues, and that histamine through their receptors causes a variety of symptoms: is a syndrome due to an enzyme deficiency.”
DAO deficiency symptoms
“The symptoms caused by a diamine oxidase deficiency can be very varied given that histamine is a molecule, a neurotransmitter, which acts in many areas of the body in many tissues […] There are usually four or five groups of symptoms:
One of them is on the skin:
-You can have symptoms similar to those of an allergy such as itching in the skin, rash redness in the skin, and so on.
Also in the Central Nervous System:
– Because it gives rise to sensations of migraines, headaches, sometimes confusing feelings
Also in the locomotor system as it can give symptoms of:
– Muscle pain, joint pains, but fundamentally muscle aches
In the digestive tract is frequent and can produce:
Type twisting aches, sometimes despenos Diarchies, it is not often but if the pain of type cramp, dyspepsia.
The histamine has a great play and a large role in the digestive tract and then also to cardiovascular level, where it is common:
-That people also may have palpitations or arrhythmias or variations in blood pressure and many variations throughout the day in blood pressure, or what i say atrial tachycardias
And then more infrequent there can also be symptoms of the reproductive system, especially in women:
What we call the dysmenorrhea, menstrual pains.
¿Which food trigger the symptoms of DAO deficieny?
“There are going to put more evident with foods rich in histamine.
Foods that already have a high content of histamine, as can be for example:
-The milk
-Eggs
-Soybeans
-Fish
-Seafood
Of all those foods that have a high content of histamine can facilitate the appearance of symptoms also foods that are high in what are called: the biogenic amines .
That is to say that are not properly but are precursors of Histamine, for example:
-The cheeses have a lot of tyramine and other biogenic amines , and then one of the foods that can easily generate these symptoms is the consumption of cheeses.

Table of rich-histamine foods (histamine content in mg/kg): aubergine 26, avocado pear 23, red wine 13, white wine 21, sparkling wine 6,3, bottle beer 2, cured meats (beicon, sausage, fuet, majorcan sausage) 350, cooked meat (ham) 5, champagne 67, fermented white cabbage (xucrut) 10-200, spinach 20-30, wheat and rice flour 5, goat cheese 87,1, cured cheese 162,1, emmental cheese 10-500, fresh cheese 5, grated cheese 556,4, roquefort cheese 2.000, yogurt 13, legumes (lentils, chickpeas and beans) 10, raw milk 389,9, mushrooms 1,8, cured meats (cured ham) 10, fresh meat (beef, pork) 4, beans 2, pasturized milk 162, olives 2, blue fish semipreserves 1.500, fresh fish 19,75, fresh blue fish (tuna, sardines) 10, frozen fish 894, fresh and frozen blue fish 2, fermented vegetable products (soya derived) 2.300, fruit juice 1,5, tomato (fresh, sauce) 0,5-8, vinegar 500, apple cicler vinegar 20, balsamic vinegar 4.000, chocolat 0,5.
This is due to the fact that in the intestine we have bacteria that are able to transform these biogenic amines into histamine through an enzyme called the histidin decarboxylase. And then alcohol also creates a lot of symptoms but by another mechanism, because alcohol blocks the activity of the enzyme diamine oxidase. So even though we do not have a very marked deficit of the enzyme, if that day we eat foods rich in histamine and furthermore, for example, we ingest alcoholic beverages: we are going to have the dual effect of a high contribution of histamine or precursor of histamine and a blockade of the enzyme.
Thus in the hours following to that type of meals we are going to be able to notice these symptoms, and then there are other drugs, for example: nonsteroidal anti-inflammatory drugs, antidepressants and a whole list of drugs that are also able to block the activity of the diamine oxidase.”

*Main drugs with inhibitory effect on Diamine Oxidase (DAO) enzyme: analgesics (metamizol, acetyl salicilic acid); antihistamines (diphenhidramine, climetidina, promethazine); anti-arrhytmics (propafenone, quinidine); anti-asthmatics (theophylline); antidepressants (amitryptiline, tranylcipromine); anti-hypertensives (dihidralazina, verapamil); atirheumatics (acemetacina); antiseptics (acriflavine); antituberculosis (isoniazid); bronchiolitics (aminophylline); cardiotonics (dobutamine); diuretics (amiloride, furosemide); expectorants (ambroxol, mucosan); mucolytics (acetylcisteine, fluimucil frenacil); antimalarials (chloroquine); antibiotics (clavulanic acid, isoniazida, augmentine, amoxiplus); antiemetics (metoclopramide, primperan); neuroleptics (haloperidol); procinetics (metoclopramide); tranquilizers (diazepam); muscle relaxants (pacuroni).

*Most representative drugs with liberating effect of endogenous histamine: analgesics (acetylsalicylic acid, meclofenamic acid, mefenamic acid, diclofenac, infometacina, ketoprofen, meperidine, morphine o animal origin); anestesics (thiopental, prolocaina, barbiturates); antitussives (codeine); cytostatics (cyclophosphamide); expectorants (ambroxol); mucolytics (acetilcysteine); muscle relaxants (D-tubocurarine, alcuroni); anti-inflammatory (naproxen).
¿Which are the functions of histamine in the body?
“Histamine, let’s say, it works as I mentioned before as a neurotransmitter, that is to say, is going to transmit nerve signals, nerve impulses between nerve cells, between neurons. Wherewith, histamine functions as a neurotransmitter in the brain. In fact, the histamine is a very important neurotransmitter involved in the vigil-sleep cycles, so that old antihistamines have the ability to move on to the brain, to cross the blood-brain barrier and block histamine receptors-brain, inducing a lot of drowsiness by that interaction with the cycles of wakefulness-sleep.
And then also histamine is a molecule that is heavily involved in the regulation of what we call: the autonomic nervous system.
The autonomic nervous system is the nervous system that regulates the function of our bodies, for example: the gastrointestinal tract, heart, breathing. Then, the histamine works joining to its receptors: when it binds to the receptor will make in that body as lower or raise the heart rate, or the gastrointestinal tract secrete acid in the stomach, do not secrete or have more bowel motility, and so on.
The fact is that histamine is involved in the regulation of the internal organs.”
¿Is DAO deficiency an allergy or it can produce allergies?
“No, the DAO deficiency is not an allergy and, in fact, yesterday a patient told me that his nutritionist was committed to that the deficit of DAO was an allergy:
– It is not an allergy, make it clear.
The mechanism by which are produced allergies is a mechanism involving the immune system through the generation of specific antibodies against allergens:
– A food,
– A pollen,
– A few mites,
– A medicine,
And every time our immune system is with that substance to which is sensitized will react, what happens, that way or one of the effects of that immune reaction is to stimulate the cells of the inflammatory system by releasing histamine. Then the symptoms that occur in an allergic reaction, such as a lot of histamine is released and that histamine will have their effects in different organs may be similar to symptoms that are generated when I have a high contribution of exogenous histamine, that is to say, or because it has consumed a lot of histamine or because I do not degrade well histamine that comes to me at the intestinal level.
But the symptoms that occur by the deficit of DAO are simply because I am not capable, if I have the deficit of DAO, to degrade adequately histamine that is coming from outside or that I’m generating in the intestine.”
¿Which treatments exist in oder to manage and prevent the symptoms of DAO deficiency?
When there is a deficit of DAO, the first thing to know is whether the DAO deficiency is of primary cause, that is, it has a genetic origin:
– That I already suffering from it means that I’m genetically predisposed to this because I am not generating adequate levels of diamine oxidase, or that is not properly diamine oxidase functioning,
Or if it is a secondary cause, i.e.:
– Because it may have some intestinal inflammation that produce that the diamine oxidase that i have in the intestine, in the intestinal mucosa, ir lowered or diminished.
So the first thing we have to do is that differentiation, because if it is a secondary deficit I will have to treat the cause that is producing that intestinal problem, that is one of the main aspects to be taken into account.
And then once that we already have made clear, the treatment is fairly similar for both cases, i.e.:
– Diet low in foods rich in histamine, or food precursors of histamine.
– Avoid alcohol and other drugs that may block the activity of the diamine oxidase.
– And then the use of preparations of diamine oxidase, i.e. exogenous products, pills containing diamine oxidase and that i can take before meals rich in histamine or if I have a very acute deficit or highly charged, because before I go to eat any kind of food, to bridge this gap that I have, that is to say, that will make me that function of degradation of histamine at the intestinal level.
And then there are also some studies that say that high doses of vitamin C, between 2 and 3 grams a day, can have a stimulatory effect of the diamine oxidase activity: of the enzyme that we already have within us, either too much or too little, but stimulates that activity.
In conclusion we can use with these three things in order to treat DAO deficiency:
– The Diet.
– Avoid the taking blocking drugs of the diamine oxidase.
– And then take exogenous products containing diamine oxidase.”
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