The effect of kiwifruit on gastrointestinal discomfort Original paper

The kiwifruit is a botanical berry with tart, sweet flesh underneath a fibrous (though edible) skin. Kiwifruit flesh is high in actinidain, an enzyme that seems to accelerate the digestion of food proteins.^[1][2][3] Based on this information, a number of studies have investigated whether eating kiwifruit can improve upper gastrointestinal discomfort.

This systematic review of 12 clinical trials examined the effect of kiwifruit ingestion on upper gastrointestinal discomfort in a total of 661 participants. The participants had functional constipation (6 trials), irritable bowel syndrome with constipation (IBS-C; 1 trial), IBS-C and functional constipation (3 trials), or no gastrointestinal disorder (2 trials).

The trials ranged in duration from 1 day to 4 weeks, with most trials lasting 4 weeks (7 trials). The forms of kiwifruit used were green (5 trials), powdered (4 trials), and gold (3 trials). In the trials using whole kiwifruit, the amounts used were 2 per day (5 trials) and 3 per day (3 trials).

The controls used for comparison were psyllium (4 trials), an inactive placebo (2 trials), prunes (1 trial), kiwifruit without actinidin (1 trial), spirulina (1 trial), and a diet without kiwifruit (1 trial). Two trials did not include a non-kiwifruit control group.

The outcomes assessed were abdominal discomfort and pain, abdominal bloating and distention, disrupted swallowing and reflux, and dyspepsia (indigestion). The investigators also pooled results from 5 trials that assessed outcomes using the Gastrointestinal Symptom Rating Scale (GSRS).

In a pooled analysis of GSRS outcomes, kiwifruit intake reduced abdominal pain and indigestion.

When reviewing all trials, the authors had the following interpretations for each of the outcomes:

• Abdominal discomfort and pain: good evidence of benefit for green kiwifruit, a possible benefit with higher doses of gold kiwifruit (i.e., 3 fruits)

• Abdominal distention and bloating: medium evidence of benefit for green kiwifruit in acute (short-term) settings, medium evidence of benefit for kiwifruit consumed chronically (long-term)

• Disrupted swallowing and reflux: limited evidence

• Indigestion: limited evidence

Most of these trials included participants with constipation. Therefore, it shouldn’t be assumed that these findings will apply to individuals without constipation.

The amount of improvement in GSRS-evaluated abdominal pain with kiwifruit intake appears to have been clinically significant, meaning that the effect would be considered noticeable and important to someone with abdominal pain who added kiwifruit to their diet.