Kiwifruit (Actinidia spp.) Dietary Consumption for Constipation: A Systematic Review and Meta-Analysis

Abstract

The aim of this systematic review is to understand if kiwifruit dietary consumption can effectively improve constipation and intestinal function. PubMed, EMBASE, and Cochrane Library were systematically searched for relevant studies from inception up to September 2021. After database search, nine clinical studies were considered eligible for inclusion. Most trials were characterised by a limited number of study participants (median: 20, min: 11, max: 79) and had a cross-over design. On average, study participants ate from two to four kiwifruits a day for a period varying from three days to four weeks. Included trials almost exclusively involved young or middle-aged adults with a high female-to-male ratio, whereas direct evidence for elderly people (>65 years old) is scant. Moderate quality evidence indicated that kiwifruit dietary consumption can improve complete bowel movements per week and decrease stool consistency in both healthy subjects and patients with constipation due to irritable bowel syndrome, probably owing to the fruit fibre and water content. Kiwifruit dietary consumption can also have beneficial effects beyond intestinal motility, such as a mild anti-inflammatory and antioxidant effect on the gut barrier, due to a combined activity of all its nutrients (enzymes, vitamins, minerals). When only patients affected by constipation were considered, kiwifruit consumption was likely associated with a short-term significant increase in defecation frequency but not always with significant changes in stool consistency. These results were also supported by studies characterised by the highest methodological quality and confirmed by the meta-analysis about the effects of kiwifruit-based interventions on defecation frequency (g = 0.576; 95% CI: (0.174; 0.978); p = 0.012). Further investigations on the topic are recommended to strengthen the consistency of current evidence with larger trials.