Constipation can greatly impact the quality of life (QoL), which can be relieved by dietary fibres; however, preserving a higher fibre intake remains a challenge. We investigated the effects of a personalised dietary advice (PDA) on fibre intake and mild constipation complaints. A total number of twenty-five adults with mild constipation complaints were included in a 4-week observation period followed by a 4-week personalised intervention. The PDA provided high-fibre alternatives via a web tool. In weeks 1, 4 and 8, dietary intake, constipation complaints and QoL were assessed. Furthermore, participants collected a faecal sample at weeks 1, 4 and 8 to determine microbiota diversity and composition, and short-chain fatty acids (SCFA). Participants completed questions daily for 8 weeks regarding abdominal complaints, stool frequency and stool consistency. Fibre intake in week 8 was significantly higher compared to week 1 (Δ = 5·7 ± 6·7 g, P < 0·001) and week 4 (Δ = 5·2 ± 6·4 g, P < 0·001). Constipation severity and QoL significantly improved at week 8 compared to the observation period (P < 0·001). A higher fibre intake significantly reduced constipation severity (β = −0·031 (−0·05; −0·01), P = 0·001) and the QoL (β = −0·022 (−0·04; −0·01), P = 0·009). Stool consistency (P = 0·040) and abdominal pain (P = 0·030) improved significantly during the intervention period (P = 0·040), but stool frequency did not. Average microbial alpha diversity and composition and SCFA concentrations did not change over time, but indicated individual-specific dynamics. Several SCFAs were associated with constipation complaints. To conclude, a PDA effectively increased fibre intake and subsequently reduced constipation complaints, indicating that guided dietary adjustments are important and feasible in the treatment of mild constipation complaints.

A comparative, randomised, double-blind trial was performed in the medical departments of five hospitals to study the effects of regular consumption of short-chain fructo-oligosaccharides (sc-FOS) on the digestive comfort of subjects with minor functional bowel disorders (FBD). In step 1, 2235 subjects were questioned to assess the incidence and intensity of digestive disorders. In step 2, 105 of these patients diagnosed with minor FBD were randomised into two groups to receive either 5 g sc-FOS or 5 g placebo (sucrose and maltodextrins) per d over a 6-week period. The incidence and intensity of digestive disorders were assessed at the end of the treatment period (day 43) using the step 1 questionnaires. A quality-of-life questionnaire was also completed at the start and end of the treatment period to assess potential effects on well-being and social performance. In step 1, 44 % of the subjects questioned presented FBD, of whom 57·1 % suffered from minor FBD. In step 2, on day 43, the intensity of digestive disorders decreased by 43·6 % in the sc-FOS group v. a 13·8 % increase in the placebo group (P = 0·026). Symptoms were experienced less frequently by 75·0 % of subjects in the sc-FOS group, while 53·8 % of controls experienced no change (P = 0·064). Using the functional digestive disorders quality of life questionnaire, the discomfort item scores increased in the sc-FOS group (P = 0·031). However, expressed as change in quality of life (improvement, worsening or unchanged), daily activities were significantly improved in the sc-FOS group (P = 0.022). Regular consumption of sc-FOS may improve digestive comfort in a working population not undergoing medical treatment.