Histamine and Mast Cell Activation

Mast cells are a type of specialized white blood cell found in organs and tissues throughout the body. They belong to a category of cells called granulocytes because they contain granules that store mediating substances that are released when the cell is activated by an immune threat, allergen or trauma. Histamine is one of the chemicals stored in and released by mast cells.

Mastocytocis is a rare disorder characterized by an excessive number of mast cells in one or more organs or organ systems within the body. Activation of mast cells results in a process called degranulation, in which the granules of immune modifiers within the mast cell are released. It is important to recognize that mast cell activation or degranulation results in not only the release of histamine, but of many other inflammatory mediators and biochemicals.

Mast cells are naturally present in the GI tract and may play a role in histamine intolerance, even otherwise healthy people who do not exhibit mastocytosis. Those with the condition may or may not have an overabundance of mast cells in the GI tract; but for those who do, the need for adequate DAO is great. For those who have GI mastocytosis and DAO deficiency, DAO supplementation becomes a matter of necessity.

It is important to understand, however, that histamine is only one of the inflammatory mediators released during mast cell activation, so the benefits of DAO-histamine management may not alleviate the all of the symptoms experienced upon degranulation.

Many people with mastocytosis find that limiting histamine intake by dietary restriction can be helpful. However, restricted diets interfere with quality of life and can be difficult to maintain effectively. Furthermore, even the most carefully managed diet can include “hidden” histamine or histamine liberators. Thus, supplemental DAO can be helpful even for those on histamine-restricted diets.