Aim
We investigated whether anti-gliadin IgG antibody (AGA-IgG) positivity is more common in patients with low-weight eating disorders than in healthy controls.
Methods
Between 2020 and 2025, female patients with low-weight eating disorders receiving inpatient or outpatient care at Hyogo Medical University Hospital and age- and sex-matched healthy controls without self-reported symptoms suggestive of gluten intolerance were recruited. AGA-IgG was measured as a marker of serological immune reactivity to gliadin. Anti-tissue transglutaminase IgA (tTG-IgA) was measured to assess celiac disease-associated serology; total serum IgA was not measured. Participants following a strict gluten-free diet were excluded because gluten restriction may reduce AGA-IgG levels. All participants provided written informed consent, and the study was approved by the Ethics Committee of Hyogo Medical University.
Results
Thirty-four patients with low-weight eating disorders (23 with anorexia nervosa [AN], 10 with avoidant/restrictive food intake disorder [ARFID], and 1 with other specified feeding or eating disorder) and 43 healthy controls were included. AGA-IgG positivity was significantly more frequent in patients than in controls (47.1% vs. 11.6%, P < 0.001). Positivity rates were 47.8% in AN and 40.0% in ARFID. Two AGA-IgG-positive patients with AN initiated a gluten-free diet during outpatient treatment and subsequently showed substantial weight gain while also receiving concurrent eating-disorder treatment.
Conclusion
AGA-IgG seropositivity was substantially more frequent in patients with low-weight eating disorders than in healthy controls. These findings suggest that heightened serological reactivity to gliadin may characterize a subgroup of patients with low-weight eating disorders. The clinical significance of AGA-IgG positivity and the specific contribution of gluten restriction to weight restoration require prospective controlled investigation.