Return to baseline arsenic concentrations after 1 year on gluten‐free diet in children with celiac disease: A prospective cohort study

Abstract Objectives Lifelong adherence to a gluten‐free diet (GFD) is the primary treatment for celiac disease (CeD). Concerns have been raised about increased exposure to contaminants in a GFD because rice, which naturally bioaccumulates arsenic and other environmental contaminants, is commonly used as a substitute for gluten. In this study, we aimed to determine whether elevated urinary arsenic and other heavy metal concentrations, previously observed after 6 months on a GFD, persisted after 12 months on a GFD. Methods Single‐center prospective longitudinal cohort study of children (age 2–18 years) with biopsy‐confirmed CeD who initiated a GFD between January and May 2022. The primary outcome was the change in urinary arsenic concentration between baseline diagnostic endoscopy and 12 months on a GFD. Results Twenty‐one of the 35 (60%) participants provided a follow‐up sample. After 12 months on a GFD, total median urinary arsenic concentration returned to baseline (3.42 vs. 4.93 μg/L, p = 0.17). The median total nail arsenic collection did not differ significantly between endoscopy and 12 months on a GFD samples ( p = 0.56). Only urinary molybdenum concentration was increased between endoscopy and 12 months of a GFD. Conclusions Children with CeD may have increased arsenic exposure as they transition to a GFD, but concentrations return to baseline within 1 year. Future studies are needed to identify dietary contributors and guide strategies to limit excess arsenic exposure.