Association of Phosphate Supplements With Refeeding Oedema in Restrictive Eating Disorders

Objective: Refeeding oedema, believed to result from the effects of insulin on renal sodium retention and subsequent oedema formation, typically occurs during the first 2 weeks after reintroduction of nutrition in individuals with severe malnutrition and can intensify body image distress in patients with eating disorders (EDs). Phosphate supplements have been found to increase insulin sensitivity, and it is hypothesised that they may also contribute to refeeding oedema in patients with EDs.

Method: In this retrospective cohort study of 633 patients with severe malnutrition due to anorexia nervosa (AN) or avoidant restrictive food intake disorder (ARFID), the impact of phosphate supplementation on the rate of weight gain was investigated.

Results: 39% of patients required treatment with phosphate supplements during their hospital course. Patients in the phosphate supplement group had significantly more weight gain than the cohort who did not receive a phosphate supplement (p < 0.05). The rate of weight gain also increased, in the phosphate supplement group, as admission body mass index decreased.

Conclusions: This is the first study to suggest that crucial phosphate supplementation contributes to refeeding oedema in patients with EDs. Future studies should seek to better understand the relationship between phosphate supplementation and weight trends in order to optimise clinical management.