THE EFFECT OF FAT ON THE pH OF THE CONTENTS OF THE DUODENUM

Abstract

The pH of the duodenal contents during digestion was investigated in dogs after feeding lean meat, meat with fat and fat alone. After meat the pH fell during the 1st hr. from the fasting level (pH 6-pH 7) to between pH 3.8 and pH 4.6. After fat the pH remained between 6 and 7. After meat with fat the pH was more variable and ranged generally higher than after meat alone. The pH range characteristic of each food was maintained after the first hr. throughout the period of observation (5-7 hrs.). Giving 50 or 100 ml. of olive oil 2 hrs. after a meat meal caused a prompt increase in duodenal pH from about pH 4 (the characteristic meat level) to between 6 and 7. Fat evidently modifies gastrointestinal activity in such a way as to render the duodenal contents neutral or only slightly acid. Presumably this is due to its influence on gastric secretion and motility. This mechanism may be of importance in providing a suitable medium for fat digestion in the duodenum.