Histamine is a natural compound found in many foods — especially aged, fermented, or leftover foods, but also in “healthy” staples: spinach, avocado, tomatoes, chocolate, fermented drinks, cheese, and even everyday meals after a long day.
Most people digest histamine just fine — because their gut produces enough of an enzyme called DAO (Diamine Oxidase), which breaks histamine down before it triggers discomfort.
But for many of us — because of gut inflammation, stress, poor sleep, genetics, hormones, aging, or diet — DAO levels drop, sometimes significantly. This means histamine from food accumulates faster than your body can clear it. The result is a cascade of unpleasant reactions: