Plasma appearance of labeled β-carotene, lutein, and retinol in humans after consumption of isotopically labeled kale

Abstract

The bioavailability of carotenoids from kale was investigated by labeling nutrients in kale with 13C, feeding the kale to seven adult volunteers, and analyzing serial plasma samples for labeled lutein, β-carotene, and retinol. Ingested doses of labeled carotenoids were 34 μmol for β-carotene and 33 μmol for lutein. Peak plasma concentrations, areas under the plasma concentration-time curves (AUCs), and percentages of dose recovered at peak plasma concentrations were calculated. Average peak plasma concentrations were 0.38, 0.068, and 0.079 μM for [13C]lutein, [13C]β-carotene, and [13C]retinol, respectively. Average AUC values (over 28 days) were 42.8, 13.6, 13.2 μM h for [13C]lutein, [13C]β-carotene, and [13C]retinol, respectively. Percentages of dose recovered at peak plasma concentrations were 3.6, 0.7, and 0.7% for [13C]lutein, [13C]β-carotene, and [13C]retinol, respectively. A positive relationship was observed between baseline plasma retinol levels and [13C]retinol plasma response.It is possible that this relationship was mediated either through some aspect of β-carotene absorption or via the common pathways of metabolism for postdose and endogenous retinoid.

Keywords

• bioavailability
• vitamin A
• liquid chromatography-mass spectrometry
• Brassica oleracea