Availability and dose response of phytophenols from a wheat bran-rich cereal product in healthy human volunteers

Scope: Phytophenols present in cereals are metabolised to compounds that could be partlyresponsible for the reduced risk of chronic diseases and all-cause mortality associated withfibre-rich diets. The bioavailability, form and in vivo concentrations of these metabolitesrequires to be established.

Materials/Methods: Eight healthy volunteers consumed a test meal containing a recommended dose (40 g) and high dose (120 g) of ready-to-eat wheat bran cereal and thesystemic and colonic metabolites determined quantitatively by LC-MS.

Conclusion: Analysis of the systemic metabolomes demonstrated that a wide range ofphytophenols were absorbed/excreted (43 metabolites) within five hours of consumption.These included 16 of the 21 major parent compounds identified in the intervention productand several of these were also found to be significantly increased in the colon. Not all of themetabolites were increased with the higher dose, suggesting some limitation in absorptiondue to intrinsic factors and/or the food matrix. Many compounds identified (e.g. ferulic acidand major metabolites) exhibit anti-inflammatory activity and impact on redox pathways. Thecombination of postprandial absorption and delivery to the colon, as well as hepatic recyclingof the metabolites at these concentrations is likely to be beneficial to both systemic and guthealth.