Normalization of Gastrointestinal Symptoms in Adults With Constipation With Daily Green Kiwifruit Consumption: Protocol for an Open-Label Intervention Study

Abstract

Background: Irritable bowel syndrome with constipation (IBS-C) and functional constipation (FC) have significant personal, health care, and social impacts, affecting patients’ quality of life. Treatment of these conditions is challenging. While green kiwifruit is a promising natural alternative to laxatives, its effectiveness in managing abdominal pain and the underlying mechanism of action is yet to be substantiated. Objective: This study investigates the effect of consuming 2 green kiwifruit daily for 4 weeks (the habitual serving) on abdominal pain and discomfort in individuals with IBS-C and FC. Methods: This study is a 2-arm parallel, open-label, placebo-controlled randomized study. This study’s duration was 9 weeks, with a 3-week lead-in phase, a 4-week intervention phase, and a 2-week follow-up phase. A total of 60 participants with IBS-C and FC were randomized to consume either 2 Zespri green kiwifruit (Actinidia deliciosa “Hayward,” ~150 g per serving, ~90 kcal) or maltodextrin (calorie-matched to the fruit, ~25 g per serving, ~90 kcal) per day for 4 weeks. The participants completed validated questionnaires assessing digestive and general health and well-being parameters, underwent magnetic resonance imaging to determine colon physiological measures, ingested a blue food dye, provided blood and fecal samples to measure microbial, immunological, and biochemical parameters, and ingested wireless motility devices (selected participants only) to assess physiological processes. Results: Recruitment for this study began in May 2021 and was completed in May 2022. A total of 63 participants were randomized, and 57 were analyzed using intention-to-treat analysis. Data analysis is complete, and full results are expected to be published in a peer-reviewed journal by April 2026. Conclusions: This study aims to evaluate the effectiveness of green kiwifruit consumption in managing abdominal pain in individuals with IBS-C and FC. It will provide new insights into the mechanisms behind the habitual consumption of green kiwifruit for digestive comfort in this population.