If I was to ask you which is the best thing to eat to help with regular bowel movements, or to help relieve constipation, most of you would probably answer with prunes. They’re a classic home remedy for helping to keep you regular thanks to their high level of sorbitol. Sorbitol is a type of dietary fibre which is able to help draw water into the lumen of the gut, and therefore can help to soften hard stools, making them easier to pass.
So how do kiwi fruits come into this then? Well, kiwi fruit have more recently been hitting the headlines for their role in constipation which could be due to a specific enzyme called actinidin. Actinidin is a digestive enzyme that breaks down proteins, improves gastric emptying and may help facilitate laxation through its stimulation of receptors in the colon. Furthermore, 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 finally, kiwis have a high water holding capacity and high viscosity, which helps with fecal bulking and softening.
Recent studies have demonstrated significant results in the treatment of constipation in healthy patients with IBS-C and in patients with functional constipation [1, 2]. 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 with 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 .
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 type Constipation were provided around 6g of fibre per day in the form of two green kiwi fruit, 12 prunes (100g) or 12 grams of psyllium over a four-week treatment period. All participants experienced similar proportions of spontaneous bowel movements. However, the participants given kiwi fruit reported fewer adverse effects than those reported by patients treated with the prunes and psyllium. Notably, a smaller proportion of patients were dissatisfied with the kiwi fruit compared with the prunes or psyllium . In addition, a randomised cross-over study looked at the effectiveness of 5g of dietary fiber from golden kiwifruit versus 5g of dietary fiber through a fibre supplement and saw similar improvements in stool consistency, straining and discomfort .
I’ve paired my mini homegrown kiwis with no added sugar granola and some raspberries, which are another source of fibre, for the best gut-loving effect.