Consuming more vitamin K may benefit bone health, a new study reports.
The name "vitamin K" refers to a group of chemically similar fat-soluble compounds called naphthoquinones. Vitamin K1 (phytonadione) is the natural form of vitamin K, which is found in plants and provides the primary source of vitamin K to humans through dietary consumption. Vitamin K2 compounds (menaquinones) are made by bacteria in the human gut and provide a smaller amount of the human vitamin K requirement. Vitamin K1 is commercially manufactured for medicinal use under several brand names (Phylloquinone®, Phytonadione®, AquaMEPHYTON®, Mephyton® and Konakion®).
Vitamin K is necessary for normal clotting of blood in humans. Specifically, vitamin K is required for the liver to make factors that are necessary for blood to coagulate (properly clot), including factor II (prothrombin), factor VII (proconvertin), factor IX (thromboplastin component) and factor X (Stuart factor). Other clotting factors that depend on vitamin K are protein C, protein S and protein Z. Deficiency of vitamin K or disturbances of liver function (for example, severe liver failure) may lead to deficiencies of clotting factors and excess bleeding.
In a new study, researchers set out to determine if dairy products enriched with calcium, vitamin D3, vitamin K1 and vitamin K2 may help improve bone metabolism in postmenopausal women. The team divided subjects into three intervention groups and one placebo group. All of the intervention groups consumed dairy products fortified with 800 milligrams of calcium and 10 micrograms of vitamin D3. Two of the intervention groups received additional supplementation with vitamin K. The treatment period lasted 12 months.
Although the scientists observed benefits in all intervention groups, they saw the most significant benefits in the women who received vitamin K. These participants experienced increases in lumbar spine bone mineral density.
The findings suggested that foods fortified with vitamin K may significantly improve measures of bone health. However, more evidence is needed to better understand these results.
For more information about vitamin K, please visit Natural Standard's Foods, Herbs & Supplements Database.