Kiwi: The Key to Constipation Relief?

A Multitude of Mechanisms

There are several proposed mechanisms underlying how this tropical fruit may exert its effect on constipation. These mechanisms are largely attributed to kiwi’s nutrient profile and its fiber content. Kiwis have a high water holding capacity and high viscosity, which helps with fecal bulking and softening. The fruit’s laxative effects may also be related to the activity of a probiotic enzyme, actinidin. Actinidin is a digestive enzyme that breaks down protein, improves gastric emptying and may facilitate laxation through its stimulation of receptors in the colon. Further, kiwis have a high polyphenol content, which may also confer digestive health benefits. Polyphenols can promote the growth of beneficial gut bacteria, such as bifidobacteria, and can fend off harmful bacteria due to their antibacterial and anti-inflammatory properties [1].

Research Findings

Recent studies have demonstrated significant results in the treatment of constipation in healthy patients with IBS-C and in patients with functional constipation [2,3]. Researchers used MRI techniques to identify the mechanism of action behind kiwi’s laxative effect and found that the consumption of two kiwi fruit daily increased water content in the small bowel and descending colon and increased colonic bulk. These MRI data are consistent with the observation that an increase in stool frequency and looser stool consistencies are seen with the consumption of two kiwi fruit daily and suggests that kiwis can be used as a natural, diet therapy for those with mild constipation [4].

Another study explored the comparative effectiveness of three natural treatments in patients with chronic constipation. This research is among the first data addressing the effectiveness and tolerability of kiwi fruit on chronic constipation in the United States. Seventy-five adults with either functional constipation or IBS-C were provided two green kiwi fruit, 12 prunes (100g) or 12 grams of psyllium daily for a four-week treatment period, each of which provides about six grams of fiber per day. All participants experienced similar proportions of complete spontaneous bowel movements. However, the patients given kiwi fruit reported fewer adverse effects than those reported by patients treated with the prunes and psyllium and a smaller proportion of patients were dissatisfied with the kiwi fruit compared with the prunes or psyllium [5]. In addition, a randomized cross-over study looked at the effectiveness of 5g of dietary fiber from golden kiwifruit versus 5g of dietary fiber from MetamucilⓇ and saw similar improvements in stool consistency, straining and discomfort [6].

Clear the Way for Kiwi

The research clearly indicates that a daily serving of kiwi fruit can help increase bowel movements and contribute to easier passage of stool. Kiwi meets the FDA criteria for a clinically effective approach to support “maintenance of normal defecation,” paving a path for it to compete with fiber powders and supplements [7]. Patients requesting “natural” treatment options may be highly receptive to kiwi as a first line intervention. Further, for patients on a low-FODMAP diet, 2-3 kiwi per day is a great fiber option compared to other high-FODMAP, high fiber foods, such as prunes and beans. It is however worth nothing that kiwi may be an allergen for some.

Our recipe for Kiwi Power Toasts using our Artisan Baker 10 Grains & Seeds is an easy, nutritious way to add kiwi to the diet. Find this recipe and more recipes to share with patients on the Schӓr website.