Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2017 May-Aug;14(2):200-206.
doi: 10.11138/ccmbm/2017.14.1.200. Epub 2017 Oct 25.

Vitamin K and bone

Maria Fusaro  1   2 , Maria Cristina Mereu  3 , Andrea Aghi  4 , Giorgio Iervasi  1 , Maurizio Gallieni  5
Affiliations
Review

Vitamin K and bone

Maria Fusaro et al. Clin Cases Miner Bone Metab. 2017 May-Aug.

Abstract

Vitamin K is mainly known as an agent involved in blood coagulation, maintaining the activity of coagulation factors in the liver. In addition, epidemiological studies suggested that a lack of vitamin K is associated with several diseases, including osteoporosis and vascular calcification. There are two main kinds of vitamin K: Phylloquinone (or PK) and Menaquinones (MKn), both act as co-enzyme of y-glutamyl carboxylase (GGCX) transforming under-carboxylated in carboxylated vitamin K dependent proteins, such as Bone Gla Protein (or Osteocalcin) and Matrix Gla Protein. Recently, Vitamin K was also identified as a ligand of the nuclear steroid and xenobiotic receptor (SXR) (in murine species Pregnane X Receptor: PXR), expressed in osteoblasts. The purpose of this literature review is to evaluate the protective role of Vitamin K in bone and vascular health.

Keywords: bone; fractures; vitamin D; vitamin K.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Biochemical structure of the main vitamin K vitamers.
Figure 2
Figure 2
Storage sites of vitamin K compounds. Vitamin K1 and MK-4 have different tissue distribution. Vitamin K1 is mainly present in the liver, heart and pancreas, while MK-4 is better represented in the kidneys, brain and pancreas. In the liver are also present long form K2: MK7 to MK13.
Figure 3
Figure 3
The vitamin K cycle. Vitamin K acts as a coenzyme. The enzyme involved in this reaction is Gamma-Glutamyl-CarboXylase (GGCX) (a). The catalyzed reaction is the carboxylation of glutamic acid residues (Glu) which are transformed into gamma-carboxyglutamic acid (Gla). Warfarin acts as a vitamin K antagonist by blocking two important reactions: vitamin K quinone reductase (b1) and Vitamin K epoxide reductase (VKOR) (b2), resulting in a consequent functional vitamin K deficiency. NADPH dependent quinone reductase (c) is relatively insensitive to the inhibiting action of warfarin and represent an escape pathway for the transformation of vitamin K quinone into vitamin K hydroquinone. MGP: Matrix Gla Protein, Gas6: Growth arrest-specific 6, GRC: Gla-rich protein, BGP: Bone Gla Protein.
See this image and copyright information in PMC

References

    1. Shearer MJ, Newman P. Metabolism and cell biology of vitamin K. Thromb Haemost. 2008;100:530e47. - PubMed
    1. Booth SL, Martini L, Peterson JW, Saltzman E, Dallal GE, Wood RJ. Dietary phylloquinone depletion and repletion in older women. J Nutr. 2003;133:2565–2569. - PubMed
    1. Schurgers LJ, Teunissen KJ, Hamulyak K, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007;109:3279–3283. - PubMed
    1. Conly JM, Stein K. The production of menaquinones (vitamin K2) by intestinal bacteria and their role in maintaining coagulation homeostasis. Prog Food Nutr Sci. 1992;16:307–343. - PubMed
    1. Walther B, Karl JP, Booth SL, Boyaval P. Menaquinones, bacteria, and the food supply: the relevance of dairy and fermented food products to vitamin K requirements. Adv Nutr. 2013;4:463–473. - PMC - PubMed

LinkOut - more resources