The effects of kiwifruit on large bowel health were investigated in healthy rats. Four-week old Sprague-Dawley rats were given diets containing 10% homogenized green kiwifruit, gold kiwifruit or 10% glucose solution (control) over 4 or 6 wk. Green kiwifruit increased the fecal output compared to control. Growth of certain bacterial species in cecum was influenced by both green and gold kiwifruit. A significant increase in cecal Lachnospiraceae in rats fed the green kiwifruit diet was observed at week 4. At week 6, green and gold kiwifruit diets assisted in improving colonic barrier function by upregulating the expression of mucin (MUC)-2, MUC3, Toll-like receptor (TLR)-4 or trefoil factor-3 genes. Gold kiwifruit consumption increased the colonic goblet cells per crypt at week 6. Significant negative correlations between E. coli and β-defensin 1 and TLR4 expression were observed. Consuming green and gold kiwifruit for 6 wk significantly altered the biomarkers of large bowel health; indicating that regularly consuming kiwifruit helps attain optimal digestive health.
This study suggests that kiwifruit need to be consumed regularly and consistently to maximize the conferred large bowel health benefits. The dietary fiber and polyphenols in kiwifruit may have been utilized as an energy source by the resident microbiota, and the alterations in microbiota composition and their metabolism may have assisted toward promoting an improved gut environment.