Absorption of triglyceride by human small intestine: dose-response relationships

Healthy subjects with ileostomies (ileostomates) were fed six breakfasts of 5-100 g linseed oil. This lipid source was chosen so that linolenic acid could be used as a fatty acid probe. Phenol red was included in the meal so that mouth-to-stoma transit could be measured as the t 1/2 of phenol red. Ileostomy effluent was collected over 24 h and the dose of lipid ingested was related to lipid output and to intestinal transit time. The coefficient of variation for mouth-to-stoma transit was less than 12%. The slopes of the least-square lines relating lipid ingested to lipid output and to mouth-to-stoma transit time were positive and significantly different (p less than 0.05) from 0. The ileostomate's small intestine absorbed linolenic acid with 98% efficiency. A delay in mouth-to-ileum transit, associated with increasing lipid loads, is one obvious mechanism that maintains the intestine's absorptive efficiency.