Abstract
Background: Constipation has significant negative personal and social impacts. Treatment for constipation is challenging. Green kiwifruit can relieve abdominal discomfort, improve laxation, increase colonic water content, and potentially modulate human gut microbiota composition.
Research Objective: The primary outcome was to assess the effect of green kiwifruit on abdominal pain in adults with constipation.
Methods: This was a randomized, open-labeled, negative controlled trial with a parallel design. Sixty participants with constipation-predominant irritable bowel syndrome and functional constipation were randomized to consume either two green kiwifruit (Actinidia deliciosa ‘Hayward,’ ~150g, ~90 kcal) or calorie-matched maltodextrin (~90 kcal = 25g) daily for four weeks. Participants completed questionnaires, underwent magnetic resonance imaging and blue food dye ingestion, and provided samples for microbiome and metabolome analysis.
Results: There was no difference in abdominal pain (p >0.05) between groups as measured by the Gastrointestinal Symptom Rating Scale (GSRS). A trend towards improvement in constipation (mean change =0.6, p =0.07; GSRS) and increased frequency of complete spontaneous bowel movements per week (mean change =1.6, p =0.07) was observed. No difference in the total colonic volume (p >0.5) was found between groups. The longitudinal relaxation time of the ascending colon was significantly higher (which reflects the presence of watery colonic chyme) in the green kiwifruit group (p =0.02). No significant differences between groups were shown in the gut microbial alpha-diversity (Shannon index, p >0.05) nor beta-diversity (Bray Curtis, p >0.05). However, the green kiwifruit group had a higher relative abundance in Akkermansia muciniphila species.
Discussion: This study provides further evidence that the consumption of green kiwifruit has a clinically relevant impact on constipation symptoms. This study demonstrated that consuming green kiwifruit for four weeks can affect colonic water content. Further high-quality trials are required to understand the underlying mechanism of action of green kiwifruit on gut function.