Roughage Revisited (The Effect on Intestinal Function of Inert Plastic Particles of Different Sizes and Shape)

The mechanisms by which dietary fiber exerts itslaxative action are not fully understood. Finelygrinding wheat bran reduces its effect. Inert plasticparticles are equipotent to bran if they consist of flakes or sliced tubing. It is not knownwhether altering the size or shape of inert particlesalters their effect on intestinal function. In arandomized crossover study, 18 volunteers swallowed 24g/day of plastic as branlike flakes or as smallgranules for 10-12 days with a two-week washout periodbetween interventions. Whole-gut transit time (WGTT),orocecal transit time (OCTT), defecation frequency, stool form, stool water content, stool pH, anddietary intake were assessed. The plastic flakes causeda 24% (P < 0.001) reduction in WGTT and a 19% (P =0.002) fall in OCTT. Resultant and appropriate changes in stool form, interdefecatoryintervals (IDI), and stool weight were seen. The smallgranules did not cause any significant change in WGTT orOCTT, although IDI did decrease and stool output and stool form score increased. The stimulanteffect of solid particles in the intestinal lumen upontransit time is influenced by the morphology of theparticles.