Do Dairy Foods Contain Vitamin K?
Vitamin K, which helps with blood clotting, bone metabolism, cell cycle regulation and cardiovascular health, is primarily found in green leafy vegetables like spinach, kale and broccoli.
However, a recent study found dairy foods are a significant dietary source of vitamin K2 – and here’s what that means.
There are two major forms of vitamin K: vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Vitamin K1 is found primarily in plant-based foods, while vitamin K2 is found primarily in animal-based foods such as dairy foods and fermented foods. The recommendation for vitamin K in the U.S. is based on vitamin K1, primarily because of insufficient research on the role of vitamin K2 in maintenance of vitamin K status.
The study examined the vitamin K content in milk, cheese and yogurt and found the amount of vitamin K2 in a dairy food is proportional to the amount of fat in the food. For example, fuller-fat varieties of cheese contain the most vitamin K2, while lower-fat varieties contain less.
This shouldn’t be surprising if we consider that vitamin K is one of four fat-soluble vitamins (along with vitamins A, D and E), so when fat is removed from dairy foods, much of the vitamin K goes with it. While the 2015 Dietary Guidelines for Americans recommends low-fat and fat-free dairy foods, they also allow up to 10% of total calories to come from saturated fat. This means that whole-fat dairy foods can fit into a calorie-balanced, healthy eating plan, as previous research has shown. One study has also shown vitamin K2 consumption is associated with a reduced risk of metabolic syndrome in adults, although more research is needed. The vitamin K content of full-fat dairy foods is one possible reason for the neutral to favorable health outcomes that have been associated with consumption of dairy foods. More research will certainly be needed to know for sure.