Kiwifruit can increase the frequency of bowel movements for people with constipation, according to researchers in New Zealand.
“In addition to improved measures of constipation status, there was a significant improvement in stool consistency, reduction in constipation, indigestion/reflux, and abdominal pain resulting in an improved overall level of GI comfort,” write Richard Gearry, MD, PhD, of the University of Otago, New Zealand, and colleagues.
Dr. Gearry and colleagues describe their international multicenter controlled trial of kiwifruit as a constipation treatment in the American Journal of Gastroenterology.
Although constipation is common, previous researchers have reported a high rate of dissatisfaction with pharmaceutical treatments.
Other components of kiwifruit, such as raphides, may alter mucin production, leading to improved laxation.
Several previous studies have suggested that regular consumption of fresh, green kiwifruit may be effective as a treatment for constipation. However, these studies have typically been small with nonstandardized endpoints, Dr. Gearry and colleagues note. In their article, they did not comment on studies of other fresh fruits or vegetables as constipation treatments.
The researchers set out to test the benefits of the fruit in a more rigorous trial. They recruited adults in New Zealand, Italy, and Japan who had either functional constipation or constipation-predominant irritable bowel syndrome (IBS-C), as well as healthy people as controls. The primary difference between functional constipation and IBS-C is that people with IBS-C experience abdominal pain along with constipation, they write.
Between June 12, 2014, and June 17, 2017, 184 participants were enrolled. Participants included 136 women and 48 men, a proportion consistent with the gender prevalence of constipation. The mean age was 30.5 years in Japan, 36.9 years in Italy, and 44.8 years in New Zealand, and the mean body mass index was 20.6 in Japan, 23.0 in Italy, and 25.4 in New Zealand.
For 2 weeks following recruitment, the participants became accustomed to recording their bowel movements with respect to frequency, completeness, spontaneity, stool form, laxative use, and degree of straining.
Participants were then randomly assigned to consume either two ripe green kiwifruit (Actinidia chinensis var. deliciosa “Hayward”) without the skins, or 7.5 g of psyllium per day for 4 weeks. Psyllium is considered a first-line treatment for both the constipation conditions with which participants were diagnosed. The fiber content of psyllium is similar to that of kiwifruit.
After 4 weeks, treatments were stopped for 4 weeks as a washout period, after which patients were switched to the other treatment for another 4 weeks.
The researchers provided them with two bisacodyl (5-g suppositories) as a pharmacologic rescue therapy.
Overall, 169 participants completed the study, and compliance with diary completion was more than 80%.
At the end of the 4-week treatment periods, the people with functional constipation who ate kiwifruit demonstrated an average increase of 1.53 bowel movements per week, a statistically significant increase (P < .0001). Those with IBS-C demonstrated an increase of 1.73 (P = .0001). Both groups reported significantly improved gastrointestinal comfort on the gastrointestinal symptom rating scale.
The frequency of bowel movements in the healthy participants did not increase.
Among those participants who took psyllium, only those with IBS-C experienced a statistically significant increase in the frequency of their bowel movements or a decrease in their gastrointestinal symptoms. Their bowel movements increased by an average of 1.87 per week (P = .0051).
The participants who ate kiwifruit reported softening of stool consistency, reduction in straining, and improvement in quality of life compared with baseline, and these improvements in straining and stool consistency were better than was reported by those who took psyllium.
“Taken in conjunction with previous clinical trials of green kiwifruit and the emerging physiological data from functional studies, consumption of two green kiwifruit can be safely recommended as an effective treatment for constipation in those with functional gastrointestinal disorders that will also provide improvements in symptoms of GI comfort,” the researchers conclude.
Two of the researchers were employed by Zespri International, a cooperative of kiwifruit growers, which partially funded the study and approved its design. The New Zealand study center trial was jointly funded by a grant from the New Zealand government.
A version of this article first appeared on Medscape.com.