Histamine isn’t the problem by itself — your ability to break it down is. • Gut health matters first: Poor bile flow lowers the gut’s natural antimicrobial defense → this increases SIBO. SIBO and gut inflammation produce more histamine. • DAO works in the gut: DAO breaks down histamine from food. If the gut lining is damaged, bile flow is poor, or you’re hypothyroid, DAO activity drops — so more histamine gets absorbed into the body. • HNMT works inside cells: When DAO can’t keep up, histamine h