12 December 2017

Two kiwi fruit a day to keep constipation at bay!

kiwi fruit

By Dr Jane Varney - Research Dietitian

Constipation is a common problem that affects around 1 in 7 people. In people with IBS, constipation is even more common, affecting almost half of all sufferers[1]. With a number of factors thought to cause the condition (inadequate fibre intake, motility problems that may cause abnormally slow intestinal transit; certain medications and disturbances in the gut microbiota), treatments for constipation vary. Commonly, these include fiber modification, exercise, medications, bio-feedback techniques and probiotics[1]. One very simple and seemingly effective therapy involves the use of the humble kiwifruit. 

Several studies have examined the role of kiwifruit in the management of constipation and/or IBS-C. For instance, one study conducted in healthy adults and those with constipation predominant IBS showed that eating 2 green kiwifruit per day for 4 weeks increased defacation frequency and reduced colonic transit time[2]. Another study in healthy, elderly people without IBS showed that daily consumption of green kiwifruit (100g kiwifruit per 30kg body weight) lead to bulkier, softer and more frequent stools[3]. Similar results were observed in a non-randomised observational study that included adults with constipation. In this study it was observed that daily consumption of 2 green kiwifruit lead to improvements complete spontaneous bowel motions, reductions in laxative use and improvements in satisfaction with bowel habit[4]. Importantly, in all of these studies, kiwifruit were shown to exert their beneficial effects without side effects.  

So, what is it in kiwifruit that may reduce constipation and improve the bowel habit? There are a number of plausible theories. For instance, the fibre component of kiwifruit is thought to have a particularly high water holding capacity and that this may facilitate stool bulking and promote laxation. Animal studies also suggest that the enzyme, Actinidin may play a role in promoting laxation, although human studies are yet to confirm these effects[5-7].

Whatever the mechanism, kiwifruit appear to be a safe and effective treatment for constipation. They are also low in FODMAPs, healthy and relatively inexpensive, making them a great addition to your everyday diet. 

  1. Ford, A.C., et al., American college of gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation. Am J Gastroenterol, 2014. 109 Suppl 1: p. S2-S26.
  2. Chang, C.C., et al., Kiwifruit improves bowel function in patients with irritable bowel syndrome with constipation. Asia Pac J Clin Nutr, 2010. 19(4): p. 451-7.
  3. Rush, E.C., et al., Kiwifruit promotes laxation in the elderly. Asia Pac J Clin Nutr, 2002. 11(2): p. 164-8.
  4. Chan, A.O., et al., Increasing dietary fiber intake in terms of kiwifruit improves constipation in Chinese patients. World J Gastroenterol, 2007. 13(35): p. 4771-5.
  5. Pastorello, E.A., et al., Identification of actinidin as the major allergen of kiwi fruit. J Allergy Clin Immunol, 1998. 101(4 Pt 1): p. 531-7.
  6. Boland, M. J. (2013). Kiwifruit proteins and enzymes: actinidin and other significant proteins. In: Advances in Food and Nutrition Research: Nutritional Benefits of Kiwifruit, pp. 59–80. Boland, M. and Moughan, P. J. (Eds.), Academic Press, Amsterdam, The Netherlands. .
  7. Montoya, C.A., et al., Actinidin from kiwifruit (Actinidia deliciosa cv. Hayward) increases the digestion and rate of gastric emptying of meat proteins in the growing pig. Br J Nutr, 2014. 111(6): p. 957-67.

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