Vitamin K Content of U.S. Dairy Foods and the Association with Fat Content

Abstract

Vitamin K is an essential nutrient that has been implicated in cardiovascular disease and other chronic diseases. There are multiple forms of vitamin K. Phylloquinone (PK, vitamin K1) is plant‐based and has been well‐quantified in the US diet. Menaquinones (MK, vitamin K2) are a class of vitamin K compounds that differ from PK in the length and saturation of their side chain. Although MK are found in animal products and fermented food, their contents of foods have not been well characterized. The objectives of this study were to: 1) quantify, using mass spectrometry technology, the different forms of MK (MK4 through MK13 in the following commonly consumed dairy foods: milk (n=40 samples), yogurt (n=17), Greek yogurt (n=16), and cheeses (n=81); and 2) compare the MK contents of full‐fat, reduced‐fat and non‐fat milk, yogurt, Greek yogurt, cottage cheese and cheddar cheese. All dairy samples were either obtained through USDA's National Food and Nutrient Analysis Program or purchased from retail outlets.Total vitamin K concentrations in full fat yogurt, Greek yogurt, cottage cheese and cheddar cheese were 28.1±18.9, 30.1±6.5, 54.2±8.3 and 28.2±41.3 μg/100 g, respectively. The total vitamin K content of blue cheese, fresh cheese, soft‐ripened cheese and semi‐soft cheese was 439±129, 309±204, 495±214 and 310±126 μg/100 g, respectively. Non‐fermented cheeses, like processed cheese, contained lower amounts of vitamin K (90.9±37.9 μg /100 g). Full fat dairy products contained appreciable amounts of MK, primarily in the forms of MK9, MK10 and MK11, which together accounted for 90% of total vitamin K in dairy foods. We also measured modest amounts of MK4 and MK12. In contrast, there was little MK5, MK6, MK7 or MK13 detected in the majority of dairy products.Total vitamin K content of full fat milk, 2% milk, 1% milk and non‐fat milk was 38.1±8.6, 19.4±7.7, 12.9±2.0 and 7.7±2.9 μg/100 g, respectively. Reduced fat or fat free dairy products (Greek yogurt, yogurt, cottage cheese and cheddar cheese) contained 8–22% of the vitamin K found in full fat products.To the best of our knowledge, this is the first report of MK contents of U.S. dairy products. The vitamin K contents are influenced by the fat content of the dairy products. If biological activity of MK from foods is established, dairy could have an important dietary role in vitamin K nutrition.Support or Funding InformationSupported by the USDA, Agricultural Research Service under Cooperative Agreement No. 58‐1950‐7‐707 and No. 58‐1235‐1‐193, and Dairy Management Inc.