Vitamin K absorption and kinetics in human subjects after consumption of 13C-labelled phylloquinone from kale

Abstract

The absorption and plasma disappearance of vitamin K were investigated by uniformly labelling phylloquinone in kale with carbon-13, and by feeding the kale to study subjects. Seven healthy volunteers ingested a single 400g serving of kale with 30g vegetable oil. The kale provided 156nmol of phylloquinone. Serial plasma samples were collected and analysed for the appearance of 13C-phylloquinone by HPLC-MS. Six of the subjects showed significant amounts of labelled phylloquinone in plasma, though one subject's plasma was not consistently enriched above the detection limit, and this subject's baseline plasma phylloquinone level was the lowest in the group. After ingestion of the labelled kale, plasma 13C-phylloquinone concentration increased rapidly to a peak between 6 and 10h, and then rapidly decreased. Average peak plasma concentration for the six subjects with detectable 13C- phylloquinone was 21nmol/l. Plasma concentration-time data were analysed by compartmental modelling. Modelling results demonstrated a mean (n 6) bioavailability of phylloquinone from kale to be 47%. Plasma and tissue half-times for phylloquinone were found to be 88 and 215h, respectively. Copyright © The Authors 2010.