Habitual Green Kiwifruit Consumption Is Associated with a Reduction in Upper Gastrointestinal Symptoms: A Systematic Scoping Review

Abstract

Kiwifruit have known positive effects on digestion. During clinical intervention trials using kiwifruit to improve constipation, upper gastrointestinal (GI) symptoms such as abdominal discomfort and pain, indigestion, and reflux were also alleviated. We aimed to evaluate the evidence for upper GI symptom relief by kiwifruit in clinical trials on participants with functional constipation (FC), irritable bowel syndrome with constipation (IBS-C), and healthy participants, and to elucidate which symptoms may be relieved and whether a difference exists between the effects of gold and green kiwifruit. We executed a systematic scoping review of 3 electronic databases from 1947 through January 2021 to identify clinical trials that reported effects of green or gold kiwifruit or kiwifruit compounds on upper GI symptoms as secondary outcomes in healthy participants or participants with FC or IBS-C. Studies were divided into those using the Gastrointestinal Symptom Rating Scale (GSRS) and those using alternative measurement tools. GSRS outcomes were pooled and statistically analyzed; non-GSRS outcomes were summarized. We identified 12 clinical trials with a total of 661 participants (124 controls, 537 receiving intervention) providing evidence for symptom relief of upper GI symptoms by kiwifruit intake. Only 5 of the 12 clinical trials used the GSRS to assess upper GI symptom relief. We found good evidence that green kiwifruit may reduce abdominal discomfort and pain, and some evidence that kiwifruit consumption may attenuate indigestion. Pooled GSRS outcome analysis indicates an average reduction of -0.85 (95% CI: -1.1, -0.57; Z = 6.1) in abdominal pain scores and -0.33 (95% CI: -0.52, -0.15; Z = -3.5) in indigestion scores with habitual kiwifruit consumption. While the number of studies reporting on upper GI symptom relief with a comparable measurement is limited, there is consistent evidence for the efficacy of kiwifruit on upper GI symptom relief. More research to strengthen the evidence is recommended.

Keywords: abdominal pain; bloating; dyspepsia; indigestion; reflux.

FIGURE 1

Study selection flowchart. GI, gastrointestinal.

FIGURE 2

The effect of habitual kiwifruit consumption on pooled mean Likert-score differences of total GSRS reflux, abdominal pain, and indigestion domains. Scores are pooled arithmetic mean differences of cases (n = 197) − pooled arithmetic mean differences of controls (n = 115); error bars are 95% CIs (Table 3). Asterisks indicate statistical significance, Z value ≤ –3. Scores are based on 15 items using Likert scores. Domain scores can range from 1 to 7, with higher scores representing higher levels of discomfort. A reduction in scores indicates symptom improvement. GSRS, Gastrointestinal Symptom Rating Scale.