The effect of dietary fibre isolates on gastric secretion, acidity and emptying.

1. In six volunteers, the effect of intragastric administration of different water-soluble chemical isolates of dietary fibre on gastric secretion, acidity and emptying was studied. 2. At 30 min after administration of the test meals, the stomach contents were completely aspirated and the volume, pH, phenol red concentration, total titratable acidity and different electrolytes were measured. 3. Compared with the control meal, the pH and unionized (combined) hydrogen concentrations were significantly higher (P less than 0.05) following most of the fibre-containing meals, while the total titratable acid concentration was not significantly different. None of the fibre-containing meals appreciably altered the volume or type of gastric secretion but had a low-grade variable effect on gastric emptying. 4. It is concluded that most dietary fibre isolates, although having a definite and notable buffering effect on the acid in the stomach, have a minimal effect on gastric secretion and a variable and small effect on gastric emptying.