The metabolic fate of anthocyanins in humans

Abstract

High intakes of anthocyanins (ACN) have been linked to decreased cardiovascular disease risk. However, due to their apparent low bioavailability, it has been postulated that phenolic degradation products of ACNs may be responsible for their bioactivity. We examined the metabolic fate of ACNs following a single dose and short‐term (12 wk) exposure to an elderberry extract, to establish the differential effects of acute v short‐term exposure on metabolism. Biological samples from a 12 wk intervention study (n=15 postmenopausal women, 500 mg/day elderberry ACNs) were analysed for ACN metabolites using HPLC‐MS/MS. 29 metabolites were identified in urine (12 ACN and 17 phenolic metabolites) and 21 in plasma (4 ACN and 17 phenolic metabolites). ACNs reached concentrations of 0.55±0.05 μM/mM creatinine in urine after 3h and 0.034 μM in plasma after 2h. The phenolic degradation products and their metabolites reached concentrations of 31.15±2.37 μM/mM creatinine in urine after 3h and 1.24 μM in plasma after 2h. The profile of metabolites was not significantly different after 12 wks of intake. These results indicate that ACNs are extensively metabolised in vivo, with little suggestion of plasma accumulation following repeated exposure. The reported bioactivity of ACN most likely relates to the high concentrations of circulating phenolic metabolites. Research support: Norwich Medical School, University of East Anglia.Grant Funding Source: Department of Nutrition, Norwich Medical School, University of East Anglia.