Plasma concentrations of dihydro-vitamin K-1 following dietary intake of a hydrogenated vitamin K-1-rich vegetable oil

Dihydro-vitamin K-1 is a dietary form of vitamin K-1 (phylloquinone) produced during the hydrogenation of vegetable oils. To determine if dihydro-vitamin K-1 is present in plasma following dietary intake of a hydrogenated fat, eight healthy adults consumed each of two diets containing 30% of calories from fat, of which 20% was either soybean oil or a partially hydrogenated soybean oil-based stick margarine. Of the fats and oils analyzed, dihydro-vitamin K-1 was only found in the hydrogenated products. The soybean oil diet contained 180 +/- 12 mu g (mean +/- SD) of vitamin K-1/day and nondetectable levels of dihydro-vitamin K-1, whereas the stick margarine diet contained 199 +/- 7 mu g of vitamin K-1/day and 23 +/- 2 mu g of dihydro-vitamin K-1/day. After consuming each diet for five weeks, plasma dihydro-vitamin K-1 concentrations were higher (P = 0.002) in all eight subjects when consuming the stick margarine diet (0.56 +/- 0.33 nmol/L) compared to the soybean oil diet (0.12 +/- 0.11 nmol/L). There was no significant change in plasma vitamin K-1 concentrations when the two diets were compared. In conclusion, dihydro-vitamin K-1 is detectable in plasma following dietary intake of a hydrogenated vitamin K-1-rich vegetable oil.