HUMAN SMALL-BOWEL MOTOR-ACTIVITY IN RESPONSE TO LIQUID MEALS OF DIFFERENT CALORIC VALUE AND DIFFERENT CHEMICAL-COMPOSITION

Previous animal studies have shown that the nature and duration of pos tprandial motility in the small bowel depend both on the caloric load and the chemical composition of a meal, It is not clear whether this i s also true for the human small bowel. Therefore we investigated the m otor activity of the human small bowel in response to nutrient liquids of different caloric value and different chemical composition. Ten hu man volunteers underwent three separate, 24-hr ambulatory manometry st udies. They drank water, a pure glucose solution, and Intralipid 10% i n volumes of both 300 and 600 mi. The caloric value of the nutrient li quids was 330 and 660 kcal, respectively. Records were analyzed visual ly for the reappearance of phase III of the MMC after ingestion of a t est liquid, and a validated computer program calculated the incidence and amplitude of contractions during the postprandial period, Neither duration of the postprandial interval nor the mean incidence or mean a mplitude of contractions were different between the fat and the carboh ydrate solutions, but phase III reappeared significantly later after i ngestion of the nutrient liquids than after water (P = 0.0002). Durati on of the postprandial interval also depended on the volume or the cal oric load of a liquid meal (P = 0.0012), Mean incidence of contraction s tended to be higher after ingestion of nutrient liquids than after w ater (P = 0.059). We conclude that in ambulant subjects, small bowel m otor activity in response to chemically diverse liquid meals is remark ably uniform. This is true for the duration of the postprandial motor activity, as well as the incidence and amplitude of contractions durin g that period. The caloric value of a liquid meal, however, regulates the duration of the postprandial interval in the human small bowel.