Published online Nov 21, 2020. doi: 10.3748/wjg.v26.i43.6706
Peer-review started: August 2, 2020
First decision: October 18, 2020
Revised: October 24, 2020
Accepted: November 2, 2020
Article in press: November 2, 2020
Published online: November 21, 2020
Core Tip: We can intake almost ordinary food even after total gastrectomy. Small intestine itself can digest and absorb food without digestion in the stomach. The pH level of gastric acid in humans is much lower than that of most animals, and very close to that of carrion-eating animals. The benefit to produce a volume of gastric acid for humans is carrion eating, in which disinfection by gastric acid is important. Now, we have decreased risk of food poisoning because of clean environment. If this hygienic environment is maintained for a long time, our gastric acid level must be decreased gradually.