Apple Pectin and a Polyphenol-Rich Apple Concentrate Are More Effective Together Than Separately on Cecal Fermentations and Plasma Lipids in Rats

Olivier Aprikian, Virgile Duclos, Sylvain Guyot†, Catherine Besson, Claudine Manach, Annick Bernalier*, Christine Morand, Christian Rémésy, and Christian Demigné

J. Lipid Res. 2005 46: 2 258-268

Abstract

To evaluate the effect of apple components on cecal fermentations and lipid metabolism, rats were fed diets containing 5 g/100 g apple pectin (PEC), 10 g/100 g high polyphenol freeze-dried apple (PL) or both (PEC + PL). The cecal pH was slightly acidic (6.49) only in rats fed the PEC + PL diet (controls, 7.02). The cecal short-chain fatty acid pool was enlarged by all the apple fractions, with a peak of 560 μmol in rats fed the PEC + PL diet compared with 189 μmol in controls. Butyrate concentrations were 2-fold greater in rats fed the PL diet than in controls. Substantial concentrations of galacturonate and succinate (≈40 mmol/L) were found in the cecum of rats fed the PEC diet and, to a lesser extent, the PEC + PL diet. The PEC + PL diet significantly lowered plasma cholesterol, whereas both the PL and PEC + PL diets lowered plasma triglycerides. Liver cholesterol and triglyceride concentrations were lower in rats fed the PEC and PEC + PL diets. Fecal bile acid excretion was markedly reduced, whereas sterol excretion was significantly increased by dietary PEC. Rats fed the PEC and PEC + PL diets also had lower apparent cholesterol absorption than controls (30 compared with 43%). In conclusion, apple pectin and the polyphenol-rich fraction were more effective when fed combined together than when fed separately on large intestine fermentations and lipid metabolism, suggesting interactions between fibers and polyphenols of apple.