The Effect of Psyllium Husk on Intestinal Microbiota in Constipated Patients and Healthy Controls.

Jonna Jalanka,Caroline Kurtz,Inmaculada Silos-Santiago,Giles Major,Jeffrey Johnston,Gulzar Singh,Willem De Vos,Kathryn Murray,Adam Nowak,Robin Spiller

doi:10.3390/ijms20020433

Abstract

Psyllium is a widely used treatment for constipation. It traps water in the intestine increasing stool water, easing defaecation and altering the colonic environment. We aimed to assess the impact of psyllium on faecal microbiota, whose key role in gut physiology is being increasingly recognised. We performed two randomised, placebo-controlled, double-blinded trials comparing 7 days of psyllium with a placebo (maltodextrin) in 8 healthy volunteers and 16 constipated patients respectively. We measured the patients’ gastrointestnal (GI) transit, faecal water content, short-chain fatty acid (SCFA) and the stool microbiota composition. While psyllium supplement had a small but significant effect on the microbial composition of healthy adults (increasing Veillonella and decreasing Subdoligranulum), in constipated subjects there were greater effects on the microbial composition (increased Lachnospira, Faecalibacterium, Phascolarctobacterium, Veillonella and Sutterella and decreased uncultured Coriobacteria and Christensenella) and alterations in the levels of acetate and propionate. We found several taxa to be associated with altered GI transit, SCFAs and faecal water content in these patients. Significant increases in three genera known to produce butyrate, Lachnospira, Roseburia and Faecalibacterium, correlated with increased faecal water. In summary, psyllium supplementation increased stool water and this was associated with significant changes in microbiota, most marked in constipated patients.

Highlights

Psyllium husk, derived from the seeds of Plantago ovata, consists of highly branched and gel-forming arabinoxylan, a polymer rich in arabinose and xylose which has limited digestibility in humans
The health-promoting effects of prebiotics include supporting the growth of bacteria beneficial to the host and increasing the production of short-chain fatty acids (SCFA) such as butyrate and propionate previously shown to be positive for colonic health [6]
The effects of psyllium husk on the intestinal microbiota in the two studies were addressed separately and microbial composition differences between the studies were only compared at baseline

Summary

Introduction

Psyllium husk, derived from the seeds of Plantago ovata, consists of highly branched and gel-forming arabinoxylan, a polymer rich in arabinose and xylose which has limited digestibility in humans. The health-promoting effects of prebiotics include supporting the growth of bacteria beneficial to the host and increasing the production of short-chain fatty acids (SCFA) such as butyrate and propionate previously shown to be positive for colonic health [6]. Another property of psyllium is that it is capable of retaining water in the small intestine, and thereby, increasing water flow into the ascending colon. The samples for this study come from two linked, published clinical trials [12] where the effect of psyllium husk on colonic volume and intestinal water content was tested on first healthy adult subjects and adults with chronic constipation. We showed that in healthy controls there was a very small change in the microbiota, there was a larger change in the microbial composition of the constipated patients

Differences Between Healthy and Constipated Patients at Baseline

The Impact of Increased Transit on Intestinal Microbiota

Analysis from Faecal Samples

Extraction of the Faecal Microbiota DNA

Analysis of the Intestinal Microbiota

Statistical Analysis