Phylloquinone absorption from phylloquinone-fortified oil is greater than from a vegetable in younger and older men and women

Studies that have compared the absorption of phylloquinone from green vegetables and oils have equivocal results. To address differences in approaches used to assess absorption of phylloquinone, a 24-h absorption study was conducted in 18 younger (20-40 y) and 18 older (60-80 y) men and women as part of a larger metabolic study that compared changes in vitamin K status in response to broccoli and phylloquinone-fortified oil (377 +/- 46 and 417 +/- 45 mug/d respectively). Absorption was defined as the 24-h area under the curve (AUC) for plasma phylloquinone concentrations (both unadjusted and adjusted for triglyceride concentrations). The mean AUC for plasma phylloquinone concentrations (both unadjusted and adjusted) were significantly greater after consumption of the phylloquinone-fortified oil diet compared with the broccoli diet (P < 0.001). However, there were no differences between the two treatments in 24-h fasting plasma phylloquinone concentrations. Although there were no age differences in the AUC for plasma phylloquinone, adjusted for triglycerides, older adults had significantly higher plasma phylloquinone concentrations (both unadjusted and adjusted) at 0 and 24 h than the younger adults (P < 0.001). These data emphasize that the use of different approaches for the assessment of vitamin K absorption can result in disparate conclusions.