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30,000 HDU | Gastrointestinal Health
DAO Enzyme contains a purified form of diamine oxidase (DAO), the primary enzyme responsible for breaking down dietary histamine in the gut before it enters systemic circulation. By supporting histamine degradation at the intestinal barrier, DAO Enzyme helps to alleviate histamine reactions from dietary triggers. This formula is highly concentrated, delivering 30,000 Histamine Degrading Units (HDUs) per capsule for effective histamine balance.
Histamine is a biogenic amine derived from histidine, and functions as a neurotransmitter, immune mediator, and local signaling molecule. It interacts with various receptors (H1–H4), leading to effects like vasodilation, inflammation, smooth muscle contraction, and sensory nerve stimulation. Histamine is present within most bodily tissues and can be synthesized in large amounts by white blood cells.
Histamine is not only produced in the body but is present in a wide range of foods produced by bacteria that decarboxylate histidine into histamine. Foods prone to high histamine content include aged or fermented products and refrigerated leftovers. Specifically, matured cheeses, cured or processed meats, fish, and fermented beverages like beer and wine commonly contain elevated histamine levels. Histamine overload may occur after consuming foods with a high histamine content that overwhelms endogenous degradation mechanisms. Even lower histamine amounts found in common food servings can provoke symptoms in sensitive individuals with compromised DAO activity or histaminergic food reactions.
Key Benefits and Features:
| Serving Size: 1 Capsule | Amount/Serving |
| Porcine Kidney Extract (DAOgest) (providing 30,000 HDU Diamine Oxidase (DAO)) | 4.2 mg |
Other Ingredients: Microcrystalline Cellulose, Delayed Release Capsule (Hypromellose, Gellan Gum), Magnesium Stearate, and Silicon Dioxide.
Does Not Contain: Gluten, corn, yeast, artificial colors, or flavors.
Take 1 capsule 15 minutes before a meal or as recommended by your healthcare professional.
Warning: If you are pregnant or nursing, consult your physician before taking this product. Keep out of the reach of children.
Storage: Keep tightly closed in a cool, dry place.
DAO and Histamine Degradation
Histamine, both endogenously synthesized and ingested through diet, can be metabolized through two pathways: methylation by histamine N-methyltransferase (HNMT) and degradation by DAO. DAO is responsible for the degradation of histamine-containing foods. Highly expressed in the intestinal mucosa, it is most active in the small intestine and is also present in the colon, kidneys, thymus, and placenta. Released into the intestinal lumen, DAO serves as a crucial protective barrier that metabolizes dietary histamine before it can be absorbed into the bloodstream.
Variability in Histamine Tolerance
Interindividual tolerance of dietary histamine is highly variable. A disruption in the balance between histamine accumulation and DAO activity has been associated with manifestations affecting the gastrointestinal tract, skin, and respiratory mucosa. Studies have shown that the degree of DAO impairment often correlates with the integrity of the intestinal barrier, leading to the proposal that DAO activity can serve as a marker of intestinal mucosal integrity. Additionally, genetic and environmental factors appear to interact in modulating DAO expression and activity; more than 50 polymorphisms in the gene encoding DAO have been identified that lead to impaired enzyme activity.
Clinical Studies
In a four-week, open-label study of 28 adults with histamine intolerance, oral DAO capsules were associated with an improvement in all 22 histamine intolerance symptoms. In the subsequent withdrawal phase, symptom scores rose again, returning toward pre-treatment levels and further supporting DAO’s effects.
Histamine has been implicated as a trigger for neurological discomfort in some individuals. A one-month, double-blind, placebo-controlled trial investigated DAO supplementation as a preventive therapy for histamine-related neurological discomfort in 100 participants with documented DAO deficiency—the DAO-treated group experienced a 1.4-hour reduction in the duration of symptoms with no adverse effects reported.





