AJP - Gastrointestinal and Liver Physiology, Vol 240, Issue 2 97-101, Copyright © 1981 by American Physiological Society
Transport and metabolism of water-soluble vitamins in intestine
R. C. Rose
An overview of intestinal absorption of water-soluble vitamins is
presented. Evidence relating to absorption of ascorbic acid by the
"sodium-gradient" hypothesis and folic acid by the "acidic microclimate"
hypothesis is discussed. Over the last decade, vitamin absorption by the
intestine has been attributed in large part to simple diffusion. Recently,
however, this view has been changing as information continues to be
gathered which suggests the participation of membrane-bound "carriers" in
transport and the involvement of cellular enzymes in metabolism of the
vitamins during absorption. The circumstances that make vitamin absorption
difficult to investigate are described. A brief look toward the future
stresses the types of information that will be helpful to acquire,
identifies some technological advances that will promote progress, and
discusses potential application of the results to health care. Some reasons
are given for confusion that has prevailed in descriptions of vitamin
absorption during the last decade; suggestions are made that might help
investigators to correct this situation.
