Inhibition of postprandial colonic motility after ingestion of an amino acid mixture

Abstract

Previous studies suggested that the ingestion of a mixture of amino acids inhibited the fatstimulated increase in colonic motility. This study determined the effect of the ingestion of an amino acid mixture on the postprandial distal colonic spike potential (SP) response to a standard 1000-calorie meal in normal subjects and in patients with the irritable bowel syndrome. The distal colonic response was measured following a standard meal with and without the preadministration of a protein hydrolysate solution. After the meal, normal subjects had their maximum response within the first 30-min postprandial period (41.0±6.3 SP/30 min). Spike activity returned to fasting activity by 60 min. Most patients with irritable bowel syndrome did not have a significant early postprandial distal colonic spike response (P>0.05), but all patients had a large late increase in spike activity occurring 60–90 min postprandially (50.0±5.0 SP/30 min) (P<0.001). Ingestion of the protein hydrolysate solution prior to the meal resulted in suppression of the early colonic spike response in normal subjects (P<0.01) and the late colonic spike response in the irritable bowel patients (P<0.01). This study suggests that amino acids can modulate postprandial colonic motility and that dietary alteration may be beneficial in the irritable bowel syndrome.