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 μg (mean±SD) of vitamin K 1 /day and nondetectable levels of dihydro‐vitamin K 1 , whereas the stick margarine diet contained 199±7 μg of vitamin K 1 /day and 23±2 μg of dihydrovitamin 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.