Science Update

Randomized Control Trial Explores Efficacy of Prebiotics for Adults With Occasional Constipation

Approximately one-third of adults 60 years of age and older report experiencing occasional constipation. Dietary and lifestyle changes are common interventions for constipation. Research has indicated that certain prebiotics may also support the body’s response to constipation.  

Prebiotics are a class of comestibles, usually carbohydrates, that have a specific effect on the gastrointestinal (GI) microbiome. To be classified as a prebiotic, the compound must not be absorbed in the GI tract and should instead be fermented by GI microbes. Prebiotics essentially stimulate the activity of the targeted intestinal microbe to help improve human health.

Examples of prebiotics include fructans, such as inulin, fructooligosaccharides, and galactooligosaccharides (GOS). These GOS have been shown in studies to stimulate several genera of beneficial microorganisms, including Bacteroidetes, Firmicutes, Enterobacteria, and in particular, Lactobacilli and Bifidobacteria.

A randomized controlled trial by Schoemaker and colleagues explored the efficacy of supplementation with probiotics in individuals with constipation. Adults between the ages of 18 and 59 were randomized to either a control group or a treatment group receiving GOS. Study results indicate that supplementation with 11 g of GOS daily for 3 weeks increased stool frequency in individuals with three or fewer bowel movements per week as compared to baseline. Improvements in stool frequency were also observed in the subgroup of adults between 35 and 59 years of age in the presence of supplementation with GOS.

The taxonomy of the gut microbiome was also analyzed in this study by Schoemaker and colleagues. Changes in the abundance of Bifidobacterium, a probiotic microorganism, have been observed in the presence of constipation. In this randomized controlled trial, Bifidobacterium was shown to have a dose-dependent response to GOS.

Supplementation with 11 g of GOS was shown to significantly increase Anaerostipes hadrus, a species in the microbiome known to produce butyrate, a short-chain fatty acid (SCFA). These SCFAs have many health-promoting roles in the human body; they have been shown to support GI and immune health. Butyrate may help support intestinal epithelial health. However, when they were measured at baseline and study terminus, no changes to the abundance of SCFAs were reported in this study.

The authors report study limitations that included gender homogeneity and errors in the self-reported quality of constipation. Response rate, relative sample size, and age variations were reported as strengths.

 Prebiotics are compounds with the potential to support a healthy GI microbiome, GI function, and overall health. They may also support the body’s response to GI conditions, such as occasional constipation.

By Colleen Ambrose, ND, MAT