There are people whose afternoon is ruined by a glass of wine, a few slices of cured meat or a piece of aged cheese. Headache, bloating, fatigue that will not lift, itching. For a long time those complaints were put down to scattered causes, until the role of an enzyme with an unfriendly name was better understood: diamine oxidase, or DAO.
Histamine and the enzyme that clears it
Histamine is naturally present in many foods, above all those that ferment, are cured or have been stored for some time: aged cheeses, cured meats, canned fish, wine or beer. DAO is the enzyme responsible for breaking it down in the gut. When its activity is low, the histamine arriving with food is not cleared fast enough and builds up. The result is a very varied range of symptoms (digestive, skin, headache, fatigue) that appears without an obvious pattern and is hard to connect to what has just been eaten.
A study done in real life
The work followed 165 adults for two months (112 women and 53 men, mean age 42.7 years) who had symptoms compatible with histamine intolerance and who took a plant-origin DAO supplement (NaturDAO) in their daily lives, at home, without changing their routine. Each participant answered a structured questionnaire at the start and another at two months, through an electronic platform.
One detail is worth highlighting: there was not a single dropout. All 165 participants completed the follow-up and provided complete data at the beginning and the end, something not always achieved even in hospital studies. This type of research falls under what is known as real-world evidence, an approach gaining weight in current research because it portrays what actually happens in people’s daily lives, with their habits and their circumstances.
The starting point
At the start, headache and migraine were the most frequent complaint (67.88 % of participants), followed by digestive problems (63.03 %) and chronic fatigue (58.79 %). Muscle or joint pain affected 38.79 % and skin problems 35.76 %.
At the table, each person identified an average of 3.5 food groups that disagreed with them. The most cited were cured and processed meats (27.27 %), aged cheeses (25.45 %), canned or smoked fish (23.03 %) and fermented foods such as yoghurt or kefir (20.00 %). Alcohol appeared in 17.58 % of cases and chocolate in 16.97 %.
The changes at two months
The table shows how many of the 165 people reported each symptom at the beginning and at the end of the period.
| Symptom | At the start | At 2 months | Change |
|---|---|---|---|
| Fatigue or lack of energy | 97 | 27 | -72.16 % |
| Skin problems | 59 | 21 | -64.41 % |
| Digestive problems | 104 | 55 | -47.12 % |
| Muscle or joint pain | 64 | 36 | -43.75 % |
| Migraine or headache | 112 | 78 | -30.36 % |
Fatigue was the symptom that gave way most: from 97 people affected down to 27, a reduction of 72.16 %. Skin complaints fell by 64.41 % and digestive problems by almost half. Improvement occurred on all five fronts assessed, without exception, which paints a coherent picture: when histamine stops building up, the benefit is not felt in one place alone but in several at once.
Less medication and more room at the table
Beyond symptoms, two results speak to quality of life. 55.76 % of participants said they needed less medication for headache, and 53.33 % noticed that they tolerated histamine-rich foods better, that is, they could eat with less fear of the consequences. A further 32.73 % had also followed a low-histamine diet, which reflects the usual approach to this situation: combining an adapted diet with a supply of the enzyme.
The underlying reading
The study leaves two useful messages. The first is that a well-structured questionnaire makes it possible to identify and follow these people in an orderly way, which is valuable in a situation usually diagnosed late and by exclusion. The second is that two months of supplementation with NaturDAO, alone or alongside dietary adjustments, was associated with clear improvements in every symptom measured, under real conditions of use and with very high adherence.
The authors note the value of continuing this line of work with larger populations and longer follow-up, to understand the long-term effect better. In the meantime, anyone who recognises themselves in this picture of symptoms has here a practical reference on what another 165 people experienced in their everyday lives.
Source
Morán J, Moles G. Observational Study on the Effectiveness of a Diamine Oxidase (DAO) Supplement in a Sample of Consumers with Histaminosis. World Journal of Food Science and Technology. 2026;10(1):15-25. DOI: 10.11648/j.wjfst.20261001.13.