Introduction

Dietary fiber is one of the most important components of food. Fulfilling regulatory and nutritional functions for the intestinal microbiota, it appears to be an essential ingredient for people with a sedentary lifestyle.

Aim: We hypothesized that regular intake of a snack containing high amounts of soluble fibre in parallel to a regular diet may rapidly improve bowel habits with simultaneous elevation of synthesis of short-chain fatty acids (SCFA).

Material and methods

A total of 20 healthy volunteers, with a stool frequency of less than 3 spontaneous bowel movements per week, completed a 14-day double-blind, parallel-arm, randomized clinical trial with the intervention comprising daily intake of 2 doses (9.99% per 100 g or 13.91% per 100 g) of fibre. Food consumption was evaluated via 72-hour recall diaries at baseline and after 14 days of intervention. Gastrointestinal symptoms (abdominal comfort, distension, bloating, flatulence, stomach rumbling, number of bowel movements) were monitored via the IBS/VAS scale every day.

Results

We found that the elevated fibre intake improved bowel habits significantly (defecation frequency increased from 0.28 to 0.87 times/day; p = 0.0002) in both study arms. After 14 days of the trial, an increase in SCFA concentration (for whole study group: acetic p < 0.036, propionic p < 0.019, and butyric acid p < 0.0012 compared to baseline parameters) with no adverse gastrointestinal symptoms was reported.

Conclusions

Short-term, regular intake of a snack containing soluble fibre improves the SCFA synthesis and bowel habits in healthy people living a sedentary lifestyle. The exact mechanism behind this observation requires further investigation.