Consuming psyllium fiber significantly reduced the frequency, but not the severity, of abdominal pain in children with irritable bowel syndrome in a randomized, double-blind, placebo-controlled trial reported in the May issue of Clinical Gastroenterology and Hepatology (2016 Nov;14[11]:1667).
Psyllium therapy did not reduce the self-reported severity of abdominal pain, Robert J. Shulman, MD, of Baylor College of Medicine in Houston reported with his associates in Clinical Gastroenterology and Hepatology. Psyllium was associated with shifts in intestinal microbiota, compared with baseline, although the changes did not reach statistical significance when compared with placebo, the researchers added. “Further studies are needed to investigate the potential mechanism whereby psyllium decreases abdominal pain frequency in children with irritable bowel syndrome [IBS],” they wrote.
IBS affects up to 20% of school-aged children. Consuming psyllium is thought to improve abdominal pain and stooling symptoms in adults with IBS, but data are inconclusive, and few randomized trials have evaluated fiber in childhood IBS. Therefore, the investigators randomly assigned 103 children (average age, 13 years; standard deviation, 3 years) with IBS who had responded inadequately to an 8-day carbohydrate elimination diet to receive a single daily dose of either psyllium or placebo maltodextrin for 6 weeks. Children aged 7-11 years received 6 g of fiber, while those aged 12-18 years received 12 g of fiber. Patients filled out a daily pain and stool diary during a 2-week baseline assessment period and again during the final 2 weeks of the trial. They also underwent breath hydrogen and methane testing, gut permeability testing, and a stool microbiota assessment during the final weekend of treatment.
At baseline, the trial arms resembled each other in terms of frequency and severity of abdominal pain, psychological characteristics, percentage of normal stools, baseline hydrogen production, and gastrointestinal permeability, the researchers said. During the final 2 weeks of treatment, the psyllium arm reported an average of 8.2 (standard deviation, 1.2) fewer episodes of abdominal pain, compared with baseline, while the control arm reported a mean reduction of 4.1 (SD, 1.3) episodes of abdominal pain (P = .03). At the end of treatment, the arms did not significantly differ in percentage of breath hydrogen or methane production, gastrointestinal permeability, or percentage of normal stools or diarrhea. However, controls had a significantly greater reduction in constipation compared with the psyllium group (P = .048).
Stool microbiome assessments of 33 children revealed a trend toward a greater increase in Bacteroidetes and a greater decrease in Firmicutes bacteria in the fiber group, compared with the control group (P = .068). The fiber group was also “marginally enriched” in bacteria of class Bacteroidia, while the placebo group was enriched in bacteria of class Clostridia (P = .094). However, the groups did not differ at narrower taxonomic levels, the researchers said. A larger sample size might have facilitated better detection of differences between groups, such as in breath hydrogen production or interactions between abdominal pain and psychological symptoms, they added.
The study was supported in part by the National Institutes of Health, the Daffy’s Foundation, and the USDA/ARS. The investigators reported having no conflicts of interest.