Variation in Gastric pH May Determine Kiwifruit’s Effect on Functional GI Disorder: An in Vitro Study

Donaldson B, Rush E, Young O, Winger R · Nutrients · 2014 April 11

Objective

To measure protein hydrolysis due to kiwifruit protease under gastric and duodenal conditions.

Conclusions

This novel finding supports the hypothesis that consumption of kiwifruit with a meal can increase the rate of protein hydrolysis, which may explain how kiwifruit relieves functional GI disorder.

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Insights

The consumption of kiwifruit with a meal can increase the rate and extent of the hydrolysis of protein.

This in vitro study has shown that in elevated gastric pH conditions, such as may present with compromised gastric function, the addition of kiwifruit protease more than doubled the rate of hydrolysis of meat protein. This novel finding supports the hypothesis that consumption of kiwifruit with a meal can increase the rate and extent of the hydrolysis of protein. Evidence is also provided that when the added acid concentration decreased from 0.074 M to 0.022 M (HCl), pepsin activity reduced by 50% and kiwifruit activity increased by 300%. This evidence indicates that kiwifruit may exert its influence on digestion by increasing the extent of protein digestion in the gastric medium when the secretion of pepsin and/or hydrochloric acid is less than optimal. It is reported [12] in a study of 365 healthy subjects, average fasting gastric pH was 2.16 ± 0.11 for men and 2.79 ± 0.18 for women, but in another study of 79 healthy elderly people [13], 11% of the participants recorded fasting gastric pH > 5.0 throughout the study.