Effects of vitamin K on bone mass and bone metabolism.
Vitamin K is involved in blood coagulation and in bone metabolism via the carboxylation of glutamate residues in (hepatic) blood coagulation factors and (osteoblastic) bone proteins. The bioavailability of nutritional vitamin K depends on the type of food, the dietary fat content, the length of the aliphatic side chain in the K-vitamer and probably also the genetically determined polymorphism of apolipoprotein E. Although undercarboxylation of blood coagulation factors is very rare, undercarboxylated osteocalcin (bone Gla-protein) is frequently found in postmenopausal women. Supplementation of these women with extra vitamin K causes the markers for bone formation to increase. In parallel, a decrease of the markers for bone resorption is frequently seen. Insufficient data are available to conclude that the regular administration of vitamin K concentrates will reduce the loss of bone mass in white women at risk for developing postmenopausal osteoporosis.
Vermeer
C
C
Department of Biochemistry and Cardiovascular Research Institute Maastricht, University of Limburg, The Netherlands.
Gijsbers
B L
BL
Crāciun
A M
AM
Groenen-van Dooren
M M
MM
Knapen
M H
MH
D000818:Animals; D001682:Biological Availability; D001842:Bone and Bones / Q000378:metabolism*; D005260:Female; D006801:Humans; D015675:Osteocalcin / Q000097:blood; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control; D014812:Vitamin K / Q000494:pharmacology*
D015675:Osteocalcin; D014812:Vitamin K