Impact of resistant starch type 3 on fecal microbiota and stool frequency in Thai adults with chronic constipation randomized clinical trial

Abstract

Constipation poses a significant health concern affecting individuals of varying ages and geographic locations worldwide. While the impacts of numerous probiotics on constipation are well-characterized, there has been limited assessment of the potential prebiotic effects of resistant starches. We therefore conducted a randomized, double-blind and placebo-controlled, clinical trial of resistant starch type 3 (RS-3) in Thai adults with self-reported chronic constipation. The effects of these mixed natural starch fibers on beneficial gut bacteria, bowel movements and stool consistency were evaluated after 6- and 12-week periods. Regardless of subject age, consumption of RS-3 compared to placebo resulted in significant improvements in gut health by dramatically increasing levels of beneficial bacteria (Bifidobacterium, Prevotella, Akkermansia and Megamonas) in the gut and relieving constipation. RS-3 consumption was associated with a significantly increased frequency of bowel movements, with subjects reporting these as healthy stools. Our findings provide important insights into the therapeutic advantages of RS-3 for constipation, and propose RS-3 as a feasible alternative strategy for management of constipation.

Fig. 1

Comparison between the cohorts after 12 weeks on Placebo or on RS-3 using: BSS scores of stool consistency (a), stool frequency scores (b), and Constipation Scoring System scores (c). Dashed lines represent the median. Dotted lines on the bottom represent the first quartile, and on the top represent the third quartile.

Fig. 2

Alpha diversity of fecal microbiota at baseline (W0), at week 6 (W6) and week 12 (W12), for cohorts on placebo and RS-3, using the alpha diversity indexes: abundance-based coverage estimators (ACEs) (a), Shannon (b), and Simpson (c).

Fig. 3

Comparison of alpha diversity between fecal microbiota from cohorts on placebo or on RS-3 for 12 weeks, using the alpha diversity indexes: abundance-based coverage estimators (ACEs) (a), Shannon (b), and Simpson (c).

Fig. 4

Principal coordinate analysis (PCoA) plots based on Bray-Curtis distance represent the comparisons of beta diversity of fecal microbiota at baseline (a), at week 6 (b) and at week 12 (c) between cohorts on placebo and RS-3.

Fig. 5

The relative abundances of the top five bacteria at the phylum level, and of the top ten bacteria at the genus level. Comparisons of the most abundant five phyla observed at baseline, week 6, and week 12, from the cohorts on placebo (a) or on RS-3 (b). Comparisons of the most abundant ten genera observed at baseline, week 6, and week 12, from the cohorts on placebo (c) or on RS-3 (d). W0, baseline data; W06, week 6 data; W12, week 12 data; *p < 0.05; and **p < 0.01.

Fig. 6

Linear discriminant analysis effect size (LEfSe) demonstrated the most significant differences between bacteria in phylum (a-b) and genus (c-d) levels in the bacterial abundant features compared between baseline (without intervention) and week 12 on either placebo (a,c) or RS-3 (b,d).

Fig. 7

Overview of clinical study and timeline of study assessments. Black diamonds, follow up of compliance by phone and/or Line; Black spheres, follow up of compliance by phone and/or Line, and collection of food/fluid intake data.