The study compared the benefits between consuming six grams of dietary fiber via two skinless kiwifruits and taking a 7.5-gram dose of psyllium (a supplement commonly used for constipation).
Participants included healthy controls and constipated individuals that had either functional constipation, IBS-C, or a combination of both. Each participant took one of the two interventions for four weeks, was given a four-week clear-out period, and then assigned the other intervention for four weeks.
Researchers found that consuming two green kiwifruits a day resulted in a clinically relevant increase of at least 1.5 complete spontaneous bowel movements for participants with constipation. When taking psyllium, only IBS-C participants saw a significant increase of 1.25 CSBM.
Gastrointestinal symptoms also improved significantly for all groups consuming kiwifruits. However, only IBS-C participants saw a significant improvement in GI symptoms when taking psyllium.
Limitations of the research included participants’ self-reporting, adherence to the intervention, food consumed, and details of bowel movements. The study was also relatively small, involving a total of 184 people.
That said, the study builds on past research around kiwifruits’ benefits for constipation. A 2022 review from the Advances of Nutrition found that green kiwifruit, gold kiwifruit, and kiwifruit supplements all positively affect upper GI health1.
A 2018 review from the European Journal of Nutrition2 credited kiwifruit’s gut health benefits to the water retention capabilities of their dietary fiber and the natural presence of the proteolytic enzyme actinidin, which contributes to easier protein digestion in the small intestine and stomach.
Researchers of the AJG publication acknowledged the work this study built upon: “Taken in conjunction with previous clinical trials of green kiwifruit and the emerging physiological data from functional studies, consumption of two green kiwifruits can be safely recommended as an effective treatment for constipation in those with functional GI disorders that will also provide improvements in symptoms of GI comfort.”