Changes in the content and forms of vitamin K in processed foods

High intake of trans fatty acids has been linked to deleterious health effects including increased risk of cardiovascular disease. Since 2006, the Food and Drug Administration requires companies to label the trans fatty acid content of foods. This has resulted in an overall decrease of commercially-hydrogenated oils in the food supply. Hydrogenation of vitamin K (VK)-rich plant oils changes the form and content of VK. It is not known if changes in use of hydrogenated oil in the U.S. food supply resulted in a change in the forms and amount of VK in processed foods. To test this, we compared 253 foods for total and individual forms of VK in foods analyzed pre- and post-2006 as part of the U.S. Department of Agriculture (USDA) Nutrient and Food Analysis Program. Overall, foods identified as rich sources of the hydrogenated form of VK pre-2006 (dihydrophylloquinone; dK) had lower amounts of dK post-2006 with a concomitant increase in the parent form of VK, phylloquinone. However, the range of dK was large within foods, suggestive of a wide range of current practices regarding use of hydrogenated oils in the U.S. food supply.