Oranges are rich sources of flavonoids that are bioactive and may protect against age-related diseases. The absorption of orange flavanones may be affected by factors such as processing and subject anthropometric variables, and the bioactivity of the absorbed phytochemicals depends on how they are metabolised during absorption. In a randomised cross-over study, twenty subjects consumed a single portion of orange fruit (150 g) or juice (300 g) that contained the flavanones narirutin and hesperidin, and an additional 109 subjects across a broad age range (18–80 years) consumed the juice. Flavanone metabolites were measured in regularly collected samples of plasma and urine. After consumption of fruit or juice, flavanone conjugates, but not the aglycones, were detected in plasma and urine. The flavanone conjugates were shown to include the 7- and 4′-O-monoglucuronides of naringenin, the 7- and 3′-O-monoglucuronides of hesperetin, two hesperetin diglucuronides and a hesperetin sulfo-glucuronide, but no aglycones or rutinosides. Analysis of the plasma pharmacokinetic and urinary excretion data on a dose-adjusted basis indicated no difference in absorption or excretion of either flavanone between the fruit and juice matrices. In the extended urinary excretion dataset the individual variation was very large (range 0–59 % urinary yield). There was a small but significant (P<0·05) decrease in the excretion of hesperetin (but not naringenin) with increasing age (P<0·05), but the effects of sex, BMI and contraceptive pill use were shown not to be associated with the variation in flavanone excretion.

Growing evidence supports a cardio-protective role for anthocyanins; however, there is limited evidence on their efficacy and safety following the consumption of relatively high but dietarily achievable doses in humans. We conducted a parallel-designed, randomized, placebo-controlled study to examine the effect of chronic consumption of anthocyanins on biomarkers of cardiovascular disease (CVD) risk and liver and kidney function in 52 healthy postmenopausal women (n = 26 in treatment and placebo groups). Volunteers (BMI, 24.7 +/- 3.6 kg/m(2); age, 58.2 +/- 5.6 y) consumed 500 mg/d anthocyanins as cyanidin glycosides (from elderberry) or placebo for 12 wk (2 capsules twice/d). At the beginning (wk 0) and end of the 12-wk intervention, levels of anthocyanins and biomarkers of CVD (inflammatory biomarkers, platelet reactivity, lipids, and glucose) and liver and kidney function (total bilirubin, albumin, urea, creatinine, alkaline phosphatase, alanine aminotransferase, and gamma-glutyl transferase) were assessed in fasted blood. Anthropometric, blood pressure, and pulse measurements were also taken. In addition, postprandial plasma anthocyanins were measured (t = 1, 2, 3 h) following a 500-mg oral bolus dose. After 12 wk of chronic exposure to anthocyanins, there was no significant change in biomarkers of CVD risk and liver and kidney function remained within clinically acceptable ranges. We observed no plasma accumulation of anthocyanins; however, postprandial metabolism increased (P = 0.02). In conclusion, these data suggest that chronic consumption of 500 mg/d of elderberry extract for 12 wk is apparently safe, but ineffective in altering biomarkers of CVD risk in healthy postmenopausal women.

The short period of blanching used to produce commercial frozen broccoli destroys myrosinase and substantially reduces sulforaphane bioavailability. Sulforaphane was converted to erucin and excreted in urine, and it was shown that human colonic flora were capable of this conversion.