DAO deficiency and the COVID-19 pandemic

We live in a time of real uncertainty with the worldwide spread of COVID-19 and anxiety levels are high. It is important to remain calm, listen and apply the advice of the Health Authority.

Considering that the activities of DR Healthcare are focused on the study of histamine, DAO deficiency and histamine intolerance, it is worth mentioning recent publications that support the fact that mast cell activation and histamine release can contribute to the inflammation associated with SARS COV-2 infection (new strain of coronavirus that causes COVID-19) .

Coronavirus infection (regardless of the various types of coronavirus) is primarily attacked by immune cells, including mast cells (MC), which are found in the submucosa of the respiratory tract and in the nasal cavity, representing a protective barrier against microorganisms. Viruses activate mast cells that release early inflammatory chemical compounds such as histamine and protease (1). In people with DAO deficiency who, due to this condition, have high levels of circulating histamine, a greater histamine accumulation caused by the aforementioned virus-activated mastocytosis, may aggravate the inflammatory process generated by the infection.

Under normal conditions, when histamine levels rise above a certain threshold, the enzymes responsible for its metabolism, specifically DAO (Diamino Oxidase) and, to a lesser extent, histamine N-methyl transferase (HNMT), rapidly degrade the excess this amine. However, when the degradation rate is insufficient to cope with the excess, the total level of histamine in the body rises. At a certain critical level, signs and symptoms occur as a result of histamine coupling to its receptors in specific cells.

Histamine is a mediator that intervenes in the inflammation of the immune system by activating intracellular pathways that induce the production of cytokines in the lungs. Cytokines are signaling proteins that regulate interactions of cells of the immune system, thus producing an amplification of inflammatory reactions.

Based on the aforementioned studies and the pathophysiology of the disease, it is important to maximize the basic recommendations to protect against COVID-19, avoiding an accumulation of histamine in people with DAO deficiency and / or mastocytosis. Since inflammation is a concern in the severity of the disease caused by SARS COV-2, it is recommended to reduce the consumption of foods high in histamine in the diet and take supplements that allow maintaining a balance between endogenous and exogenous histamine, avoiding an excess of histamine in the body, and therefore reducing the mast cell / histamine load.

Thus, in addition to the basic general guidelines to prevent the spread of COVID-19 in the entire population, there are a number of added recommendations to consider in people with DAO deficiency and / or intolerance to histamine:

-Avoid eating foods with a high concentration of histamine or other biogenic amines that compete for the DAO enzyme. These include, for example, raw, pasteurized milk and dairy products; citrus, strawberries and banana; seafood, blue fish and fish sauces; the raw sausage, such as sausage, chorizo ​​or bacon; some vegetables, such as tomato, spinach or eggplant, as well as alcoholic beverages.

-Oral supply of DAO enzyme to prevent systemic absorption of exogenous or dietary histamine. This facilitates the metabolism of food histamine locally in the small intestine, restoring the natural balance of histamine and DAO.

DAOfood® Plus contains the DAO enzyme that complements the body’s own enzyme and increases the degradation capacity of exogenous histamine. It also contains Quercetin that acts as an adjuvant against endogenous histamine. Its intake prevents the absorption and accumulation of circulating histamine and therefore counteracts the release of endogenous histamine as a reaction of the body when it comes into contact with the virus.

It is important to note that because SARS COV-2 is classified as a new strain of coronavirus, there is limited scientific evidence available on its precise mode of action and infection. Therefore, what is indicated in this article is based on what we know so far and on the importance of protecting against the virus, while maintaining control of mastocytosis and DAO deficiency.

The DR Healthcare team is at your entire disposal in case of concern about the implications of COVID-19 in people with DAO deficiency.


1.-        Kritas, S. K., Ronconi, G., Caraffa, A., Gallenga, C. E., Ross, R., & Conti, P. (2020). Mast cells contribute to coronavirus-induced inflammation: new anti-inflammatory strategy. Journal of biological regulators and homeostatic agents34(1), 10.23812/20-Editorial-Kritas.