Dihydro-vitamin K-1: Primary food sources and estimated dietary intakes in the American diet

Dihydro-vitamin K-1 was recently identified as a dietary form of vitamin K produced during the hydrogenation of vitamin K-1-rich vegetable oils. Dihydro-vitamin K-1 is absorbed, with measurable levels in human plasma following dietary intake. To determine the primary food sources of dihydro-vitamin K-1 in the American diet, 261 foods from the U.S. Food and Drug Administration's (FDA) Total Diet Study (TDS) were analyzed by high-performance liquid chromatography. Of these foods, 36 contained dihydro-vitamin K-1. Fast-food items that were otherwise poor sources of vitamin K-1, such as french fries and fried chicken, contained appreciable amounts of dihydro-vitamin K-1 (36 and 18 mu g/100 g, respectively). These nutrient values were then applied to the FDA TDS consumption model to determine average dietary intake of dihydro-vitamin K-1 in 14 age-gender groups. With the exception of infants, all age-gender groups had estimated mean daily dihydro-vitamin K-1 intakes of 12-24 mu g, compared to mean daily vitamin K-1 intakes of 24-86 mu g. The vitamin K-1 and dihydro-vitamin K-1 intakes were summed, and the dietary contribution of dihydro-vitamin K-1 was expressed as a percentage of total vitamin K intake. Children reported the highest intakes of dihydro-vitamin K-1 (30% of total vitamin K intake), followed by a progressive decrease in percentage contribution with age. There are currently no data on the relative bioavailability of dihydro-vitamin K-1 but, given its abundance in the American diet, this hydrogenated form of vitamin K warrants further investigation.