Efficacy of actinidin-containing kiwifruit extract Zyactinase on constipation: a randomised double-blinded placebo-controlled clinical trial

Asia Pac J Clin Nutr. 2018;27(3):564-571. doi: 10.6133/apjcn.122017.03.


Background and objectives: Zyactinase® is an extract of green kiwifruit, formulated into the consumer healthcare products marketed as Phloe® and Kivia, used to assist in the relief of the symptoms associated with a range of digestive system dysfunction, including constipation and Irritable Bowel Syndrome (IBS).

Methods and study design: A randomised, double-blind, placebo-controlled clinical trial was undertaken to determine the ef-fects of the kiwifruit extract on bowel movement, stool formation and IBS associated symptoms amongst a sub-ject group of generally healthy individuals experiencing a period of moderate constipation. Fifty-eight partici-pants were randomized to the kiwifruit extract (28) or placebo (30). Selection criterion was decreased number of bowel movements (<3/week), with increased faecal hardness and IBS associated symptoms. The study ran for three weeks, with participants first undergoing a seven-day wash out period, followed by a seven-day dosing pe-riod, and then a seven-day follow up period.

Results: There was a significant increase in the defecation frequency (p<0.001), with a significant improvement in faecal score (p<0.01). There was a significant difference in pain-ful defecation and abdominal pain between the two groups (p<0.01). No side effects, including diarrhoea, urgen-cy or abdominal pain, were observed during the trial.

Conclusions: The green kiwifruit extract significantly in-duced normal bowel movements with no adverse effects. The kiwifruit extract relieved constipation and the symptoms of IBS such as bloating, flatulence and abdominal pain.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Actinidia / chemistry*
  • Adolescent
  • Adult
  • Constipation / drug therapy*
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / pharmacology*
  • Double-Blind Method
  • Feces
  • Fruit / chemistry*
  • Humans
  • Middle Aged
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Young Adult


  • Plant Extracts
  • Cysteine Endopeptidases
  • actinidain