Plasma concentrations of dihydro-vitamin K1 following dietary intake of a hydrogenated vitamin K1-rich vegetable oil

Dihydro-vitamin K₁ is a dietary form of vitamin K₁ (phylloquinone) produced during the hydrogenation of vegetable oils. To determine if dihydro-vitamin K₁ 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 K₁ was only found in the hydrogenated products. The soybean oil diet contained 180 ±12 μg (mean±SD) of vitamin K₁/day and nondetectable levels of dihydro-vitamin K₁, whereas the stick margarine diet contained 199±7 μg of vitamin K₁/day and 23±2 μg of dihydrovitamin K₁/day. After consuming each diet for five weeks, plasma dihydro-vitamin K₁ 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 K₁ concentrations when the two diets were compared. In conclusion, dihydro-vitamin K₁ is detectable in plasma following dietary intake of a hydrogenated vitamin K₁-rich vegetable oil.