Comparison of the digestive tolerance of an oligomeric versus a polymeric oral nutritional supplement in people with anorexia nervosa. A randomised crossover clinical trial.

Abstract Background: Most people with anorexia nervosa (pAN) have digestive symptoms, which affect tolerance to nutritional treatment. Oligomeric oral nutritional supplements could be better absorbed than polymeric ones and better tolerated. Objectives: to compare, in pAN, an oligomeric versus a polymeric nutritional supplement with respect to digestive tolerance (primary objective) and sensory perception (secondary objective). Methods: Randomised, crossover, double-blind, controlled clinical trial. Inclusion criteria: male or female aged 12–50 years with anorexia nervosa treated at the Unidad de Trastornos de la Conducta Alimentaria del Hospital Regional Universitario de Málaga, Spain. Participants were randomised to first receive a container of the oligomeric or polymeric supplement. A digestive symptom questionnaire was administered, which they completed again after taking the supplement, together with a questionnaire for sensory evaluation of the supplement. One week later, they received a container of the other type of supplement, and the process was repeated. Analysis was performed on a per protocol basis. Results: 10 people were randomised to the oligomeric-polymeric sequence and 12 to the polymeric-oligomeric one, of whom 9 and 11 were tested, respectively. There were no statistically significant differences in digestive symptoms between the two supplements. The oligomeric one scored lower on taste and higher on acidity. Median (interquartile range) for oligomeric and polymeric respectively: taste 6.5 (4), 8(3), p 0.03; acidity 0 (1), 0 (0), p 0.01. Conclusions: In pAN, oligomeric nutritional supplements have a similar digestive tolerance to polymeric ones, and are perceived as having a worse taste and a higher degree of acidity. Trial registration: The trial is registered at ClinicalTrials.gov, number NCT05184738.