# Abstract

 

## Purpose Increased awareness of the importance of dietary fibre has led to increased interest in "functional" fibre components like digestion-resistant maltodextrin (RMD). This randomized, placebo-controlled, double-blind study assessed the effects of RMD in the colonic transit time (CTT) and defecation characteristics (frequency, stool volume and consistency). 

## Methods Sixty-six healthy adult volunteers (32 men) who did not have a daily defecation habit had a 7-day run-in period before the 21-day intervention period with RMD or placebo. CTT and segmental CTT (SCTT) were assessed by a single abdominal X-ray film taken at the end of both periods after radiopaque marker ingestion. Defecation characteristics and intestinal functions were also assessed, which were self-reported by patients. Intragroup comparisons were evaluated by Student's paired *t* test, Bonferroni test and Chi-square test, while time comparisons by analysis of variance (ANOVA) and time-by-treatment interaction by repeated-measures ANOVA. 

## Results Fifty-seven subjects were assessed for CTT (placebo, *n* = 28; RMD, *n* = 29). In the RMD group, the total CTT, left SCTT and rectosigmoidal SCTT decreased significantly compared to baseline (*p* \< 0.01 each; −13.3, −4.7, −8.7 h, respectively). Significant differences between groups were observed in total CTT and left SCTT. Significant time-by-treatment interaction was observed in the RMD group for stool volume (*p* = 0.014), increasing 56 % compared to baseline (*p* \< 0.01), while remained unchanged in the placebo group. Stool consistency was improved only in the RMD group (*p* \< 0.01). No adverse effects related to study products were observed. 

## Conclusions The results show that RMD improved CTT, stool volume, stool consistency and some intestinal functions in a healthy population. # Results 

## Baseline data A total of 73 candidates were assessed for eligibility, and 67 subjects met the criteria and were randomly allocated into two groups. One subject was withdrawn during the run-in period before receiving intervention (Fig. [1](#)). Thus, a total of 66 subjects were analysed, 33 in each study group. The demographic and other baseline characteristics of subjects in each group are outlined in Table [1](#). Briefly, the population was 51.5 % female with the mean age of 21.3 years and the mean BMI 23.0 kg/m^2^. The two study groups were well balanced with respect to demographics and baseline characteristics, and no significant difference was found in any of the variables between groups. The mean daily fibre intake was 10.0 ± 4.6 g in the RMD group and 11.5 ± 4.6 g in the placebo group. Overall, no significant differences in the diet were observed between groups. <figure> <p><img src="" /></p> <figcaption>Disposition of subjects for placebo (maltodextrin) and digestion-resistant maltodextrin (RMD) groups</figcaption> </figure> ::::table-wrap

::: caption
Demographics and baseline characteristics of subjects
:::

```
                 Placebo (*n* = 33)   RMD (*n* = 33)   Total (*n* = 66)
```

______________________________________________________________________

Female, *n* (%) 17 (51.5) 17 (51.5) 34 (51.5)
Age (years)^a^ 21.5 ± 3.2 21.1 ± 2.4 21.3 ± 2.8
Height (m)^a^ 1.73 ± 0.1 1.72 ± 0.1 1.7 ± 0.1
Weight (kg)^a^ 70.3 ± 14.0 67.5 ± 12.3 69.0 ± 13.1
BMI (kg/m^2^)^a^ 23.3 ± 3.0 22.7 ± 3.0 23.0 ± 3.0
Smoker, *n* (%) 10 (30.3) 8 (24.2) 18 (27.3)

*RMD* digestion-resistant maltodextrin, *m* metres, *kg* kilograms,
*BMI* body mass index, *n* number of subjects

^a^Values expressed as mean ± SD (standard deviation):::: 

## Colonic transit time Although 66 subjects completed the study, 9 subjects (5 in placebo and 4 in RMD groups) failed to complete CTT determination due to non-compliance. Consequently, data from 57 subjects were used to measure CTT and SCTT. The total CTT, left SCTT and rectosigmoidal SCTT were significantly decreased in the RMD group after intervention compared to baseline (*p* \< 0.004, *p* \< 0.008 and *p* \< 0.006, respectively), while no decrease was found in the placebo group. There are significant differences observed between groups regarding the total CTT and left SCTT (*p* \< 0.028 and *p* \< 0.001, respectively; Table [2](#)). Placebo intervention did not yield any decrease for the total CTT and SCTT. Additionally, stratified analysis by gender did not show differences between placebo and RMD groups for CTT and SCTT (data not shown). ::::table-wrap
::: caption
Change in total, right, left and rectosigmoidal colonic transit time for
each group after 3-week intervention
:::

Colonic transit time (h) Treatment Baseline Week 3 *Δ*

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Total colon RMD 53.0 ± 23.9 39.7 ± 22.3\*\* −13.3 ± 21.6^#^
Placebo 48.4 ± 24.1 48.0 ± 25.0 −0.4 ± 21.4\
Right colon RMD 12.3 ± 8.0 12.3 ± 8.7 0.1 ± 9.6
Placebo 12.6 ± 12.8 12.4 ± 9.4 −0.2 ± 10.7\
Left colon RMD 14.9 ± 9.9 10.2 ± 8.6\*\* −4.7 ± 8.8^

##^
Placebo 9.4 ± 9.1 12.1 ± 9.5\* 2.7 ± 6.5\
Rectosigmoidal colon RMD 25.9 ± 18.1 17.2 ± 14.6\*\* −8.7 ± 15.4
Placebo 26.5 ± 13.1 23.6 ± 16.0 −2.9 ± 18.7

Values expressed as mean ± SD (standard deviation)

*Δ*: change from baseline to week 3

\* *p* \< 0.05; \*\* *p* \< 0.01, intragroup significant difference
(Student's paired *t* test)

^#^*p* \< 0.05; ^

##^ *p* \< 0.01, intergroup significant differences
(ANOVA):::: 

## Intestinal function endpoints The defecation frequency, stool volume, stool consistency and the number of Rome III positive criteria between the two groups did not differ at baseline. After the intervention period, there were significant increases in defecation frequency in both groups compared to baseline (RMD 65.8 %, placebo 56.1 %; *p* \< 0.01 each). By contrast, the stool volume evolved differently between two groups. There were significant increases found in the RMD group at Week 1, 2, and 3 (31, 32, 56 %; *p* \< 0.006, *p* \< 0.006, *p* \< 0.0001, respectively) compared to baseline, while in the placebo group there were no changes found during intervention (Table [3](#)). Furthermore, there was a significant time-by-treatment interaction observed in stool volume (*p* = 0.014). Based on the Bristol Scale Score self-recorded, a significant increase (softer and better stool consistency) was observed in the RMD group after 3 weeks (21.4 %, *p* \< 0.01) compared to baseline. No change was observed in the placebo group for the stool consistency. Regarding the total number of Rome III positive criteria, there were significant reductions in both RMD and placebo groups (*p* \< 0.01 each). ::::table-wrap
::: caption
Change in stool volume and stool consistency for each group during
3-week intervention
:::

```
                          Baseline      Week 1          Week 2          Week 3               *p* value^†^ time × treatment
```

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Stool volume (cm^3^/day)\
RMD 53.4 ± 30.1 69.9 ± 27.4\* 70.2 ± 27.3\* 83.4 ± 26.6\* 0.014
(*Δ*) (16.6 ± 32.9) (16.8 ± 31.2) (30.0 ± 27.4)^

##^\
Placebo 56.4 ± 20.6 59.4 ± 25.0 64.3 ± 25.1 65.6 ± 23.8\
(*Δ*) (3.0 ± 21.4) (7.9 ± 24.8) (9.2 ± 20.0)\
Stool consistency (score)\
RMD 2.8 ± 1.2 3.0 ± 1.0 3.0 ± 1.2 3.4 ± 1.0\* n.s.
(*Δ*) (0.3 ± 1.0) (0.3 ± 1.2) (0.6 ± 0.8)\
Placebo 2.8 ± 0.8 3.2 ± 0.8 3.2 ± 0.7 3.2 ± 0.5\
(*Δ*) (0.4 ± 1.0) (0.4 ± 0.9) (0.4 ± 0.8)

Values expressed as mean ± SD (standard deviation

*Δ*: change from baseline to each time point; n.s.: no significant

\* *p* \< 0.05, intragroup significant difference (Bonferroni)

^†^*p* for time-by-treatment interaction was assessed by a
repeated-measures ANOVA

^

##^*p* \< 0.01, intergroup significant differences (ANOVA):::: Interestingly, analysis of the individual Rome III criteria showed that only after intervention with RMD a significant lower number of subjects (compared to baseline) answered positively to 3 out of 6 criteria: "straining" (from 63.6 to 33.3 %; *p* \< 0.025), "sensation of incomplete evacuation" (from 51.5 to 27.3 %; *p* \< 0.003) in at least 25 % of defecations, as well as "fewer than three defecations per week" (from 24.2 to 0.0 %; *p* \< 0.013). 

## Safety During the study, six AEs were recorded (2 in placebo and 4 in RMD groups). None of the AEs were related to the study products nor classified as serious. These events were: ankle sprain, cervical muscle spasm, otitis, fever and diarrhoea. There were no clinically relevant changes observed in the biochemical parameters by haematological examination.


Extracted trial result:
Outcome: Improvement in faeces consistency (continuous)
Intervention: Digestion-resistant maltodextrin
Comparator: Placebo
Intervention group size: 33
Intervention mean: 3.4
Intervention standard deviation: 1
Comparator group size: 33
Comparator mean: 3.2
Comparator standard deviation: 0.5