HistaGest-DAO™ provides supplemental diamine oxidase (DAO), the enzyme responsible for breaking down food-derived histamine, to help support normal and healthy histamine metabolism.* Histamine is a bioactive compound produced in the body in response to an injury or the presence of foreign substances and is present in all foods in the diet in various degrees. Some foods are known to be high in histamines, such as fermented foods and alcoholic beverages. Lower DAO activity may result in higher levels of histamine being absorbed through the small intestine and accumulating in the blood.