Effects of a polyphenol-rich extract blend, probiotics, and hydrolyzed fiber on quality of life and gut health markers in patients with irritable bowel syndrome-A randomized, double-blind, placebo-controlled trial

Abstract

Introduction: Irritable bowel syndrome (IBS) is the most prevalent functional bowel disorder impacting around 5%-10% of the general population worldwide. The pathogenesis remains unclear, however alterations in gut-brain axis play a critical role. We aimed to investigate the therapeutic potential of a novel synbiotic formulation comprising of partially hydrolyzed guar gum (PHGG), specific probiotic strains (Bifidobacterium and Saccharomyces boulardii), and double-standardized, polyphenol-rich blend of extracts from Aronia melanocarpa and Sambucus nigra in patients with IBS.

Methods: A total of 47 patients with IBS were randomly assigned to three groups and followed over a 2-month study period. Group I (n = 14) received placebo capsules, Group II (n = 14) took one placebo capsule along with a probiotic formulation and PHGG, Group III (n = 19) received probiotic formulation, PHGG and polyphenol-rich fruit extracts blend. The IBS-quality of life (QoL) questionnaire was completed by all participants at baseline and after 2 months. Serum levels of IL-6, IL-8, TNF-α, I-FABP-2, GM-CSF and stool concentrations of short-chain fatty acids (SCFAs) and zonulin were evaluated before and after intervention.

Results and conclusions: This study demonstrated a significant improvement in QoL in individuals receiving the complete formulation combination (Group III). The largest decrease in score was observed in dysphoria, with median differences of -5 in Group III (p = 0.0021), -3 in Group II (p = 0.0155), and -1 in the control Group I (p = 0.0338). Significant correlations were found in Groups II and III between supplementation and serum concentrations of IL-8, TNF, and GM-CSF (p < 0.05). A significantly higher concentration of all SCFAs was seen after intervention in Group III compared to control Group I.

Keywords: FODMAP; SCFAs; dietary intervention; fiber; irritable bowel syndrome; polyphenols; probiotics; quality of life.

Figure 1

Schematic overview of the study design. Created with BioRender.com. Skrzypczak-Zielinska, M. (2025) https://BioRender.com/d13p202.

Figure 2

IBS-QoL score comparison results for studied patients Group before and after intervention. (A) heatmap with mean values of received punctation for each 34 IBS-QoL items. (B) plots for eight IBS-QoL score subgroups. The boxes represent the mean values with Q1–Q3 and min-max after statistical comparison performed by Wilcoxon test, *indicates statistical significance at p < 0.05, **p < 0.01.

Figure 3

Serum markers and stool zonulin concentration before and after supplementation. The boxes represent the mean values with Q1–Q3 and min-max. Statistical differences identified by Wilcoxon test at *p < 0.05, **p < 0.01 and ***p < 0.001.

Figure 4

Stool consistency among IBS subtypes and studied patients Groups before and after supplementation. Circles and triangles represent individual participant results, with lines connecting each participant's pre- and post-supplementation measurements. Statistical differences identified by Wilcoxon test at *p < 0.05, and ***p < 0.001.

Figure 5

Fecal short-chain fatty acids (SCFAs) concentrations in studied IBS patient Group before and after supplementation. The boxes represent the mean values with Q1–Q3 and min-max after statistical comparison performed by Wilcoxon test, *indicates statistical significance at p < 0.05, **p < 0.01.