Short-Term Daily Intake of Polydextrose Fiber Does Not Shorten Intestinal Transit Time in Constipated Adults: A Randomized Controlled Trial

Peter Duncan,Maurice Beaumont,Catherine Enters-Weijnen,Tiago Nunes,Peter Mclean,Niek Dewit,Nashmil Emami,Diederick Grobbee,Teunis Weits,Rafael Crabbe,Gabriela Bergonzelli,S Scott,Kevin Whelan

doi:10.3390/nu10070920

Abstract

Chronic constipation (CC) remains a common gastrointestinal (GI) disorder that conveys a substantial healthcare burden. Expert guidelines recommend increasing fiber intake, yet the clinical evidence to support this needs strengthening for specific fibers. The aim was to evaluate changes in intestinal transit time and GI symptoms in CC patients who consumed polydextrose. In a randomized, double-blind, placebo-controlled trial, 128 adults with CC received 8 g or 12 g polydextrose, or placebo, daily for 4 weeks. Transit time, as primary outcome, was assessed by radiopaque marker distribution after 2-weeks intervention. Bowel habits, GI symptoms and quality of life (QOL) were assessed by questionnaire, including the Patient-Assessment of Constipation (PAC) Symptoms (SYM), and PAC-QOL. Following 2-weeks intervention, no reduction was seen in transit time in any group and following 2- or 4-weeks intervention, no improvements were seen in stool frequency or consistency in any group. After 2-weeks intervention with 8 g/day polydextrose an improvement was seen in the PAC-SYM rectal score (p = 0.041). After 4-weeks intervention both rectal (p = 0.049) and stool (p = 0.029) scores improved while improvement in the QOL satisfaction score did not reach significance (p = 0.071). Overall, the results suggest that 2-weeks consumption of 8 or 12 g/day polydextrose does not significantly improve physiological measures of gut function in CC adults. Longer term consumption may improve clinical measures, but further studies will be required to substantiate this.

Highlights

Chronic constipation (CC) is a common, heterogeneous, symptom-based GI disorder, with a global pooled prevalence in adults of 14–16%, though prevalence rates vary considerably depending on defining criteria [1,2]
Regional colon transit times suggested that the change seen in whole GI transit time (WGTT) with the 12 g/day difference 9.3, 95%CI 2.2–16.5, p = 0.01)
The positive impact that consumption of polydextrose has been reported to have on bowel function [36,37] led us to hypothesize that 8–12 g/day of polydextrose would lead to a reduction in WGTT and improve symptoms of constipation in adults

Summary

Introduction

Chronic constipation (CC) is a common, heterogeneous, symptom-based GI disorder, with a global pooled prevalence in adults of 14–16%, though prevalence rates vary considerably depending on defining criteria [1,2]. In the absence of an organic cause, characteristic symptoms of CC include infrequent and difficult defecation, feeling of incomplete evacuation, passage of hard stools, and associated abdominal discomfort and bloating [3,4,5]; there is considerable overlap with constipation-predominant irritable bowel syndrome [2,6,7,8]. Pathophysiology of CC is multifactorial and incompletely understood. It can be broadly considered an overlap between GI/colonic dysmotility (manifested as delayed gut or colonic transit) and impairment of rectal evacuation/pelvic floor dysfunction, which can be due to several identified structural or ‘functional’. The importance of abnormal colorectal sensation [13] and gut dysbiosis [14]

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