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.*
The enzyme diamine oxidase (DAO) degrades histamine by converting it from 2-(4-imidazolyl)- ethylamine to the inactive metabolite imidazole acetaldehyde. The active ingredient in G.I. Hist Support is porcine-derived diamine oxidase, and research suggests that DAO derived from porcine kidney appears to have identical action to DAO derived from porcine intestine. In humans and other mammals, DAO is found in high concentrations in the gastrointestinal mucosa.
Diamine oxidase from Porcine is the body’s primary enzyme for breaking down ingested histamine and a natural defense against histamine excess. If you ingest too much dietary histamine or produce more than your DAO level can handle, reactions can occur. DAO is produced in the small intestine but certain drugs, foods and bacteria may suppress its production.
Low DAO levels are associated with the following symptoms and conditions:
- Migraine, headaches
- Hives, skin rash, eczema
- Nasal congestion, stuffy or runny nose
- Gastrointestinal disorders, inflammation
- Estrogen dominance
- Nerve and/or muscular pain
- Joint inflammation
- Neurological conditions such ADHD
- Depression and anxiety
Symptoms of low DAO are similar to those of histamine excess since it is the DAO that breaks down and metabolizes the histamine. Patients suffering from urticaria (hives) or bowel irritation lack the ability to break down histamine. Since DAO is made in the gastrointestinal tract, low levels are also indicative of poor digestive function and a compromised intestinal barrier.