The effect of meal volume and fat content on gastroesophageal reflux was investigated in 20 asymptomatic healthy subjects. In each subject, intraesophageal pH monitoring was performed during a 3-hr postprandial period (PP) in the same position (supine or upright) on two successive days. On day 1, 500-ml low- and high-fat meals were ingested and, on day 2, an 800-ml low-fat meal was ingested. The acid exposure time was assessed as the percentage of time with a pH < 4.0. The acid exposure time in subjects in the upright position was significantly longer in the 800-ml group than in the 500-ml group for the entire PP (2.7 +/- 1.5%; mean +/- SE, 0.7 +/- 0.4%; P < 0.05). Of subjects in the supine position, the high-fat group showed significantly longer acid exposure time than the low-fat group both for the entire PP (7.6 +/- 3.0%, 0.7 +/- 0.5%; p < 0.05) and for the second hour (P < 0.05). We have demonstrated that differences in the meal volume and fat content influence gastroesophageal reflux in healthy asymptomatic subjects and that this influence varies with the position.

This study examined the effect of body position on lower esophageal sphincter (LES) pressure. In 36 healthy subjects and 31 patients with reflux esophagitis, LES and intragastric pressures were measured with subjects in the supine and sitting positions by the intraluminal microtransducer method. LES pressure was significantly lower in the sitting position than in the supine position in both healthy subjects and patients with reflux esophagitis. Intragastric pressure was significantly higher in the sitting position than in the supine position in both healthy subjects and patients with reflux esophagitis, but this increase was less marked than the decrease in LES pressure in the sitting position. The overlap of LES pressure values between healthy subjects and patients with reflux esophagitis was lower in the sitting position than in the supine position. We conclude that the measurement of LES pressure in the sitting position reflects LES function more accurately.

We investigated the effect of body position and ingestion of a test liquid meal on esophageal acid exposure time in 20 asymptomatic healthy subjects. Intraesophageal pH monitoring was performed for 1 h before meals and 3h postprandially with the subject in the supine (n = 10) or sitting position (n = 10). The test meal had a total volume of 800 ml and an energy content of 500 kcal. Esophageal acid exposure time was defined as the percentage of time at pH < 4.0. There was no difference in preprandial or postprandial esophageal acid exposure time between the supine and sitting positions. Esophageal acid exposure time for the 3-h postprandial period was significantly greater than that for the preprandial period in both the supine and the sitting positions. The difference in body position did not influence preprandial or postprandial esophageal acid exposure time, but ingestion of the liquid meal significantly increased the esophageal acid exposure time in both the supine and sitting positions in asymptomatic healthy subjects.

No abstract

No abstract