AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 2 184-G191, Copyright © 1985 by American Physiological Society
Effect of dietary cellulose on site of lipid absorption
D. Gallaher and B. O. Schneeman
The effect of dietary cellulose on the localization within the small
intestine of isotopically labeled triglyceride (TG) and cholesterol (CH)
from a test meal was investigated. Feeding a 20% cellulose meal resulted in
greater quantities of 14C-TG present in both the contents and mucosa of the
distal intestine compared with a fiber-free control meal. In contrast,
cellulose had no effect on the localization of CH within either the
intestinal contents or the mucosa. Accumulation of TG within the intestine
was not due to differences in stomach emptying, as the emptying rate was
similar for both TG and CH. Within the bulk phase TG must be hydrolyzed by
pancreatic lipase before it is available for cellular uptake at the
microvillus membrane, whereas CH requires no hydrolysis. The greater amount
of TG, but not of CH, within the intestine suggests that cellulose can
interfere with lipase activity in vivo. Consequently, cellulose can delay
TG hydrolysis and increase the amount of lipid absorbed in the ileum.
