Mixed dishes are an unexpected source of dietary vitamin K

摘要

Variable vitamin K intake can result in unanticipated interactions with stability of coumarin based anticoagulant medications. Current recommendations emphasize a consistent intake of vitamin K-rich foods while taking these medications. The high vitamin K content of certain vegetables is well known, but current and comprehensive data on the vitamin K content of mixed dishes are lacking. The objective of this study was to characterize and quantify the amount of vitamin K per serving of various mixed dishes in a representative US sample. Food samples were obtained from the USDA Nutrient Data Laboratory as part of the National Food and Nutrient Analysis Program, and analyzed for three vitamin K forms (phylloquinone, 2',3'-dihydro-phylloquine, and menaquinone-4) using high performance liquid chromatography. Foods were classified into high or moderate vitamin K-containing in accordance with the Nutrition Care Manual. Out of the 47 mixed dishes analyzed, 1 was high and 16 were moderate in vitamin K content, with 12 of these dishes containing no appreciable amounts of vitamin K-rich vegetables. Mixed dishes, even those that do not contain vitamin-K rich vegetables, can contain substantial amounts of vitamin K from plant oils and animal products. These findings contribute to our knowledge of vitamin K sources in the US diet, and have important clinical implications for those prescribed oral anticoagulants that are vitamin K-antagonists.