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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Shahkhalili, Y. Articles by Fern, E. Search for Related Content PubMed PubMed Citation Articles by Shahkhalili, Y. Articles by Fern, E.

Effects of Foods Rich in Polyphenols on Nitrogen Excretion in Rats¹

Nestlé Research Centre, Nestec LTD., Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland

The extent to which tea, cocoa and carob (foods rich in polyphenols) influence fecal nitrogen (N) excretion was investigated in rats. The studies took into account the methylxanthine contents of tea and cocoa as well as the poor digestibility of cocoa nitrogen. Balance measurements indicated that all three food sources significantly increased fecal nitrogen excretion relative to methylxanthine-matched control diets (p < 0.01). In the case of cocoa, virtually all the increase could be attributed to the poor digestibility of cocoa protein itself (estimated to be only 28–30% of total N in cocoa powder). There appeared to be no other effects. With extracts of tea and carob, however, the increased excretion of N in feces resulted either from a decreased digestibility of other dietary protein, through interaction with their polyphenols, or from a stimulation of the excretion of endogenous (body) nitrogen. With respect to the latter possibility, a preliminary investigation with the stable isotope of nitrogen (¹⁵N) showed that tea produced a marked increase in the excretion of endogenous nitrogen. These studies, therefore, indicate that foods rich in polyphenols have varying effects on N excretion in feces and that, in the case of tea at least, the loss of endogenous nitrogen may be a major contributing factor.

KEY WORDS: • polyphenols • tea • cocoa • carob • nitrogen • rats

¹ Part of this work was presented as a poster at XIII International Congress of Nutrition, Brighton, U.K. (1985).

² To whom correspondence should be addressed.

Manuscript received 21 March 1989. Revision accepted 6 October 1989.

This article has been cited by other articles:

				L. Perez-Olleros, M. Garcia-Cuevas, and B. Ruiz-Roso Nota. Influencia de la pulpa y fibra natural de algarrobas sobre algunos aspectos de la utilizacion nutritiva de la dieta y la colesterolemia en ratas / Note. Influence of pulp and natural carob fiber on some aspects of nutritional utilization and cholesterolemia in rats Food Science and Technology International, January 1, 1999; 5(5): 425 - 430. [Abstract] [PDF]