Evidence from clinical and observational studies indicates that histamine levels are elevated in migraine sufferers and that interventions targeting histamine metabolism can reduce migraine symptoms (Izquierdo-Domínguez et al., 2018; Öztürk et al., 2003).
Multiple studies (e.g., Sicuteri et al., 1982; Öztürk et al., 2003) show elevated histamine levels in migraine patients, and clinical trials involving DAO supplementation (Izquierdo-Domínguez et al., 2018) demonstrate that managing histamine improves migraine outcomes. No papers refute the core claim.