Bone Health - Importance of Vitamin K

By: Alere Staff

Most people think of calcium and vitamin D as being important nutrients for strong and healthy bones. Did you also know that vitamin K is equally important to long term bone health?

Vitamin K is a fat-soluble vitamin that helps with normal blood clotting. Warfarin (or brand of warfarin such as Coumadin®) prevents the normal effect of vitamin K on clotting.1 Vitamin K’s role in bone health is to assist cells in the bone to maintain normal bone density. It also helps to produce a protein which promotes calcium absorption by the bones instead of it being deposited in soft tissue such as the lining of our blood vessels.3

Vitamin K is not a single nutrient, but actually a group of vitamins. The two main groups of vitamin K are vitamin K1 (phylloquinone) and K2 (menaquinone). K1 is found in many green leafy vegetables.2 K2 is produced by bacteria and is found in foods such as meat, liver, butter, egg yolk, cheese, curd cheese and fermented soy products.3 The K2 form is the most biologically active form of Vitamin K.4

The National Academy of Sciences recommends a daily adequate intake of vitamin K at 90 mcg for adult women and 120 mcg for adult men. These levels are the minimum recommended amount.5

People taking warfarin are usually cautioned to be aware of how much vitamin K they consume in their daily diet. Patients taking warfarin should not completely eliminate vitamin K from their diet. A stable and consistent intake of vitamin K is important for bone health and to enable proper dosing of warfarin. When considering any increased vitamin K intake while taking warfarin, it should be discussed with your doctor. More frequent INR testing will be needed during this time to ensure proper dosing of your warfarin to keep it in the prescribed target range.

More frequent testing, typically performed by patient self-testing, is a valuable tool for detecting rises and falls in INR values and enable you to work with your doctor to make any adjustments to diet or medication dosing.6 Studies have shown that increasing testing frequency with weekly testing of INR improves patient safety and helps keep the drug in its therapeutic effective zone.6,7 Weekly testing was shown to be the most effective testing frequency.Go to the Getting Started page or call Alere at 1.800.504.4032 for more information about testing your INR at home.

  1. Weber, P. Vitamin K and bone health. Nutrition. 2001 Oct;17(10):880-7.
  2. Booth, S.L., Suttie, J.W. Dietary Intake and Adequacy of Vitamin K1. J. Nutr. May 1, 1998 vol. 128 no. 5 785-788.
  3. Better Bones. “Nutrition & bone health”.Dr. Susan E. Brown, PhD. Published 01/01/2009. Modified 07/10/2012. Accessed 6/04/2013.
  4. Schurgers L.J., Vermeer C. Determination of Phylloquinone and Menaquinones in Food. Haemostasis. 2000;30:298–307.
  5. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: The National Academies Press, 2001.
  6. Am J Manag Care. 2014;20(3):202-209.
  7. Heneghan C., et al. Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. 2006. Lancet, 367, 404-11.


COUMADIN® is a registered trademark of Bristol-Myers Squibb Pharma Company. Alere is not affiliated or associated with Bristol-Myers Squibb Pharma Company or the COUMADIN® trademark.