Histamine Enzyme is a patented enzyme formula containing Diamine Oxidase (DAO)—the main enzyme responsible for the degradation of ingested histamine. This enzyme has been clinically tested and found to break down food-derived histamine in the digestive tract. DAO is not absorbed and does not have systemic activity. Histamine Enzyme does not manage or address antibody-related or IgE-related food allergies.* Histamine is a bioactive or “vasoactive” amine produced in the body in response to an injury or foreign substance. It has an array of physiological effects, including increasing blood supply to specific sites in the body. In addition, histamine is involved in the immune response, regulation of gastric acid, permeability of blood vessels, contraction of muscles, and the normal response to inflammation. The highest concentrations of histamine in the body are found in the gastrointestinal tract, lungs, and skin, with lesser amounts in the brain and heart.* Histamine is not only produced in the body but is also present in many fermented foods, such as sauerkraut, sausage, cheese, yogurt, and alcoholic beverages. Tuna, olives, spinach, eggplant, avocados, tomatoes, cherries, and citrus fruits are other histamine-containing foods. Despite their absence of histamine, some foods, such as berries, tea, and a variety of spices, stimulate the endogenous production of the amine due to their benzoate content. In addition, microbial fermentation can convert the histidine in high-protein foods to histamine so that the histamine content of food can increase over time.