Abstract
- Background
Inulin is a soluble dietary fibre, also classified as a prebiotic, extracted from chicory roots. The present study aimed to determine the effect of consumption of native chicory inulin on the stool frequency of middle-aged to older adults with uncomfortably but not clinically relevant low stool frequency, specified as two to four days without bowel movements per week. Two randomised, double blind, placebo-controlled crossover trials were conducted using similar protocols in differing populations. Trial A was conducted in Amsterdam, The Netherlands and subsequently Trial B was conducted in Newcastle, United Kingdom.
- Methods
Both trials involved supplementation for 5 weeks with 10 g per day of inulin or placebo, a washout period of 2 weeks, and then crossed over to receive the other treatment. In Trial B, faecal gut microbiota composition was assessed using 16S rRNA gene sequencing. In Trial A, which 10 volunteers completed, the stool frequency was measured during inulin versus placebo periods. In Trial B, 20 volunteers completed the protocol. Combining the data of low stool frequency subjects from both trials was also performed. Regarding secondary outcomes, stool consistency was assessed using the Bristol stool scale, and other bowel habit parameters and microbiota diversity were evaluated.
- Results
In Trial A, the stool frequency was significantly increased to an average of 4.9 times per week during inulin periods versus 3.6 in the periods with placebo. In contrast, in Trial B, there was no significant effect of the inulin on stool frequency, though many subjects in Trial B had a stool frequency greater than 5 per week also for the placebo period, in breach of the inclusion criteria. Combining the data of 16 low stool frequency subjects from Trials A and B showed a significant effect of inulin to increase stool frequency from 4.1 to 5.0 per week. Stool consistency was significantly softer with inulin treatment compared to placebo periods, increasing on the Bristol stool scale when data from all subjects were combined. No other differences in bowel habit parameters or specific bacterial abundance, alpha, or beta diversity were significant, although trends were in directions consistent with published studies on other types of inulin.
- Conclusions
We conclude that 10 g per day of native chicory inulin can increase stool frequency in subjects with low stool frequency.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6686634/