Bioavailability of wild blueberry (poly)phenols at different levels of intake

BACKGROUND: Data from human intervention studies have highlighted potential cardiovascular benefits of blueberry (poly)phenols. However, such biological effects are dependent on their bioavailability and, as such, information on the absorption, metabolism and excretion of such compounds is necessary. OBJECTIVE: To investigate whether the bioavailability of blueberry (poly)phenols is intake-dependent, a group of nine healthy volunteers consumed three wild blueberry drinks containing 766 mg(lower), 1278 mg(medium) and 1791 mg(higher) total (poly)phenols, corresponding to 34, 56 and 80 g, respectively, freeze-dried blueberry powder. METHODS: Plasma levels of (poly)phenol metabolites were assessed at baseline and at 1, 2, 4 and 6 hours post-consumption, using UPLC-Q-TOF mass spectrometry. RESULTS: Twenty-three phenolic acid metabolites were quantified in plasma after blueberry consumption. Increases in plasma (poly)phenol metabolites were observed in all the interventions tested. The area under the curve of the concentration over time (AUC) significantly increased when comparing the lower and higher (poly)phenol interventions. Linear dose-response regressions were obtained for 11 metabolites, while the plasma concentration of the remaining 12 metabolites was not affected by increasing amounts of (poly)phenols in the blueberry interventions. CONCLUSION: Absorption and metabolism of blueberry (poly)phenols are not exclusively intake-dependent at the amounts tested, evidencing a complex metabolic fate of these compounds.