No Effect of Glucomannan on Body Weight Reduction in Children and Adolescents with Overweight and Obesity: A Randomized Controlled Trial

J Pediatr. 2019 Aug;211:85-91.e1. doi: 10.1016/j.jpeds.2019.03.044. Epub 2019 Apr 26.


Objective: To assess the efficacy of water-soluble dietary fiber, glucomannan supplementation, on the body mass index (BMI) in children with overweight or obesity.

Study design: In this randomized, double-blind, placebo-controlled trial, we enrolled 96 children aged 6-17 years with overweight or obesity based on the World Health Organization growth criteria (>+1 SD or >+2 SD, respectively). Participants were assigned to receive glucomannan or placebo (maltodextrin), both at a dose of 3 g/d for 12 weeks and were followed up for the next 12 weeks. Concomitant care included dietary and lifestyle advice. The primary outcome was the difference in the BMI-for-age z score change between the groups at 12 weeks.

Results: Compared with the placebo, glucomannan had no effect on the BMI-for-age z score at 12 weeks (mean difference: 0.0, 95% CI -0.1 to 0.1). Compared with the placebo, the glucomannan group had lower total and low-density lipoprotein cholesterol concentrations at 12 weeks. In addition, the blood pressure was greater at 12 weeks (systolic) and at 24 weeks (diastolic) in the glucomannan group. No differences between the groups in adverse events and other secondary outcomes were observed.

Conclusions: Glucomannan supplementation compared with placebo had no effect on weight reduction in children with overweight and obesity.

Trial registration: ClinicalTrials.govNCT02280772.

Keywords: amorphophallus; fiber; konjac.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Body Mass Index
  • Body Weight*
  • Child
  • Cholesterol, HDL / blood
  • Diastole
  • Dietary Supplements*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Mannans / administration & dosage*
  • Overweight / therapy*
  • Pediatric Obesity / therapy*
  • Polysaccharides
  • Solubility
  • Systole
  • Treatment Outcome
  • Weight Loss*
  • Weight Reduction Programs


  • Cholesterol, HDL
  • Mannans
  • Polysaccharides
  • (1-6)-alpha-glucomannan
  • maltodextrin

Associated data