Effect of the dietary fiber glucomannan on chronic constipation in neurologically impaired children

J Pediatr. 2000 Jan;136(1):41-5. doi: 10.1016/s0022-3476(00)90047-7.


Objective: Inadequate dietary fiber intake is a widely accepted explanation for chronic constipation in children with severe brain damage. The aim of our study was to evaluate the efficacy of glucomannan, a soluble fiber, as a treatment for chronic constipation in these children.

Study design: Twenty children with severe brain damage and chronic constipation were randomly assigned to double-blind treatment with either glucomannan (n = 10) or placebo (n = 10) for 12 weeks. Stool habits, total and segmental gastrointestinal transit times, and anorectal motility were evaluated in all children before and after the treatment period.

Results: Glucomannan significantly increased (P <.01) stool frequency, whereas the effect of placebo was not significant. Laxative or suppository use was significantly reduced (P <.01) by glucomannan but was not affected by placebo. Clinical scores of stool consistency were significantly improved and episodes of painful defecation per week were significantly reduced by glucomannan (P <.01) but not by placebo. However, neither glucomannan nor placebo had a measurable effect on total and segmental transit times.

Conclusions: In neurologically impaired children, glucomannan improves stool frequency but has no effect on colonic motility.

Publication types

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

MeSH terms

  • Administration, Rectal
  • Anal Canal / physiology
  • Brain Damage, Chronic / complications*
  • Cathartics / therapeutic use*
  • Child, Preschool
  • Chronic Disease
  • Colon / physiology
  • Constipation / diet therapy*
  • Defecation / physiology
  • Dietary Fiber / therapeutic use*
  • Double-Blind Method
  • Feces
  • Female
  • Follow-Up Studies
  • Gastrointestinal Motility / physiology
  • Gastrointestinal Transit / physiology
  • Humans
  • Intellectual Disability / complications
  • Male
  • Mannans / therapeutic use*
  • Placebos
  • Rectum / physiology
  • Suppositories


  • Cathartics
  • Dietary Fiber
  • Mannans
  • Placebos
  • Suppositories
  • (1-6)-alpha-glucomannan