Vitamin K status of free-living subjects consuming olestra

The potential for 20 g olestra/d to affect vitamin K status was assessed in a 6-wk study involving 202 free-living subjects. Functional prothrombin [Simplastin (S)-Ecarin (E) assay] concentrations and classical clotting times were unaffected by olestra. Initial S:E values were 0.80 and 0.79 for the olestra and placebo groups, respectively, compared with a value of 0.92 for normal reference plasma. At week 6 the value was 0.81 for both groups. Mean phylloquinone serum concentrations, expressed as differences from baseline, were not significantly different between groups. Weekly food diaries indicated that the average phylloquinone intake of the subjects was low, approximately 60 micrograms/d. Sensitive measures of vitamin K status were unaffected in a population where any significant decrease in phylloquinone bioavailability should have been reflected in those measures, indicating that 20 g olestra/d in the diet did not affect vitamin K status.