THE RELATIONSHIP BETWEEN GASTRIC PH AND THE EMPTYING OF SOLID, SEMISOLID AND LIQUID MEALS

The effect of three different meal constituents, solid, semisolid and liquid, on gastric pH, recorded in the proximal and distal stomach, wa s evaluated in a prospective study of 20 normal volunteers. The solid and liquid were ingested together as one meal and the semisolid as ano ther. Simultaneous recordings of the rate of gastric emptying of the i sotopically labelled meal constituents and the gastric pH were made. T he rate of gastric emptying was more rapid for the liquid and semisoli d constituents (t(1/2) = 35.6, range 9.8-103.3 min and 47.4, range 33. 5-120 min, respectively) than for the solid meal constituent (t(1/2) = 72.0, range 45.0-103.8 min), P < 0.01. Both the combined meal of soli d and liquid and the semisolid meal produced a higher pH response in t he proximal stomach than in the distal stomach (5.2, range 2.4-6.1 vs 2.9, range 0.8-5.3 and 5.9, range 4.3-6.6 vs 4.3, range 1.1-5.9), P < 0.01. There were significant correlations be tween the rate of gastric emptying of all three meal constituents and the decline phase in the gastric pH recorded at both the proximal and distal probes, P < 0.01 ( Pearson's correlation). The strongest correlations were found between the rate of gastric emptying and the gastric pH recorded in the proxim al stomach. The decline phase of gastric pH followed the emptying of s emisolid more closely than the emptying of either solid or liquid.