3.6. Metabolic Impact of Cocoa Diet on the Urinary Metabolic Profiles of Rats
Massot-Cladera, M. *; Mayneris-Perxachs, J.; Swann, J.R.; Costabile, A.; Castell, M.; Pérez-Cano, F.J.
Background and Objectives
Cocoa contains fiber and polyphenols that influence the intestinal ecosystem by affecting the growth of certain species of rat’s gut microbiota (Massot-Cladera, M., et al. Arch. Biochem. Biophys. 2012, 527, 105–112; Massot-Cladera, M., et al. Br. J. Nutr. 2014, 112, 1944–1954; Massot-Cladera, M., et al. J. Funct. Foods 2015, 19, 341–352. The aim of the present study was to ascertain whether cocoa also modulates bacterial metabolism and also to establish the particular involvement of cocoa fiber in such effects.
For this purpose, Wistar rats were fed, for three weeks, a standard diet (REF), a diet containing 10% cocoa (providing a final proportion of 0.4% of polyphenols, 0.85% of soluble fiber and 2.55% of insoluble fiber) (C10), a diet with the same soluble and insoluble fiber proportion from cocoa as the C10 diet, but with a very low amount of polyphenols (<0.02%) (CF) or a reference fiber diet (I) containing 0.85% soluble fiber as inulin. After two weeks of intervention, rats were maintained in metabolic cages for 24 h to collect urine output. Urine was centrifuged and frozen at ´80 ˝C until NMR analysis.
Results and Conclusions
There were no differences between the two reference diets (REF and I diets). Animals fed the C10 diet excreted higher levels of epicatechin than those from the I and CF groups. Although both the C10 (OPLSDA model Q2Y = 0.68) and the CF (Q2Y = 0.88) groups excreted more caffeine, theobromine, theophylline, paraxanthine, and malonate than the I group, the C10 diet group excreted higher amounts of these metabolites. Moreover, C10-fed animals excreted higher amounts of 2-oxoglutarate, citrate, choline, allantoin, N-acetylglycoprotein, hippurate, sucrose and glucose than the CF-fed animals. Due to the fact that the C10 diet had a higher impact on the urinary metabolic profile than the CF diet, it is likely that other cocoa compounds, rather than cocoa fiber, are responsible for these effects.