QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Reinhold, J. G. Articles by Garzon, P. Search for Related Content PubMed PubMed Citation Articles by Reinhold, J. G. Articles by Garzon, P.

Retention of Iron by Rat Intestine in Vivo as Affected by Dietary Fiber, Ascorbate and Citrate¹

Research Center for the Study of Nutrition, School of Veterinary Medicine and Animal Science, University of Guadalajara ^* Biochemical-Pharmacology Division, Unidad de Investigacion Biomedica de Occidente, IMSS, Guadalajara, Jalisco, Mexico

The effects of pH, ascorbate, citrate and dietary fiber on retention of ferrous and ferric iron by jejuno-ileal segments of rat intestine were examined in vivo. Iron was introduced in an isosmotic solution of sodium chloride and dextrose buffered by 2-[bis(2-hydroxyethyl)amino]ethanesulfonic acid (BES) and acetate. Stabilization of the iron solutions was aided by use of iron concentrations 1 µg/ml injected into the intestine for 10-min periods. Iron retention was optimal over a broad pH range from 5 to 7.8. Inclusion of ascorbic acid in the solution injected (5, 25 or 75 µg/ml) did not increase retention of iron in either valence state. A low concentration of sodium citrate (2 mM) had no effect on iron retention, but increasing the concentration to 5 mM released iron from the mucosa. Maize and wheat fibers decreased the retention of ferrous iron by binding and by promoting autoxidation and formation of poorly soluble iron polymers. Bound ferrous iron was released completely at pH below 5. Retention of ferric iron was also lowered in the presence of fiber, presumably as a result of polymerization. Retention of iron by the rat in the absence of ligands was independent of valence state.

KEY WORDS: • iron bioavailability • dietary fiber • ascorbate • citrate

¹ These studies were sponsored by the University of Guadalajara and the Subsecretariat of Higher Education and Scientific Investigation, Grant 79-04-70.

² To whom correspondence should be addressed at P.O. Box 1-3838, Guadalajara, Jalisco, Mexico.

Manuscript received 4 February 1985. Revision accepted 3 February 1986.