AUTHOR=Buck Patrizia , Goebel-Stengel Miriam , Mack Isabelle , Zipfel Stephan , Stengel Andreas 

TITLE=Case report: Carbohydrate malabsorption in inpatients with anorexia nervosa

JOURNAL=Frontiers in Psychiatry

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2022.1076658

DOI=10.3389/fpsyt.2022.1076658

ISSN=1664-0640

ABSTRACT=Background
Gastrointestinal (GI) complaints are frequently observed in patients who suffer from anorexia nervosa (AN). These symptoms may hamper treatment and weight regain and are often perceived as cause, not consequence, of the disease. Since carbohydrate malabsorption also produces these symptoms, this might underly or contribute to these complaints. So far, the role of carbohydrate malabsorption (fructose malabsorption and lactose intolerance) in AN has not yet been investigated.

Methods
For this case series, inpatients with AN (n = 7) conducted hydrogen breath tests with 25 g fructose and 50 g lactose to investigate carbohydrate malabsorption. Results were then analyzed in association with body mass index (BMI) and patient-reported outcomes (disordered eating, body image disturbances, anxiety, depressiveness, perceived stress and GI complaints). 

Results
By means of the hydrogen values three of the seven female patients were classified as lactose intolerant, one with fructose malabsorption. Both hydrogen curves for fructose (r = - 0.632, p < 0.001) and lactose (r = - 0.704, p < 0.001) showed a negative correlation with BMI. No association was observed between hydrogen values and patient-reported outcomes.

Conclusions
GI symptoms in patients with AN caused by common mono- and disaccharides may be an underestimated burden and should be considered in diagnosis and therapy of patients with AN. Due to the observed correlation with BMI, this likely develops with decreasing body weight and is potentially reversible with weight regain.