Vitamin K nutrition and osteoporosis.
Although the abundance of vitamin K-dependent proteins in bone suggests an important function, the precise role of vitamin K in skeletal health remains to be determined. Serum concentrations of vitamin K are reportedly reduced in older individuals and persons with osteoporotic fracture. Whether this is causally related to vitamin K insufficiency or simply reflects inadequate nutritional status is unclear. Circulating levels of undercarboxylated osteocalcin may be a sensitive marker of vitamin K inadequacy and have been reported to be increased in both postmenopausal women and individuals who sustained hip fracture. It is also possible that vitamin K indirectly affects the skeleton via control of renal calcium excretion. The effect of vitamin K antagonists (oral anticoagulants) on both renal calcium excretion and bone density is controversial. Thus, many of the reports implicating a role for vitamin K insufficiency in the development of osteoporosis are conflicting. This review summarizes current knowledge regarding a possible role of vitamin K insufficiency in the pathogenesis of osteoporosis.
Binkley
N C
NC
Department of Medicine, Medical School, University of Wisconsin-Madison 53706, USA.
Suttie
J W
JW
D000368:Aged; D000595:Amino Acid Sequence; D002135:Calcium-Binding Proteins / Q000737:chemistry; D016326:Extracellular Matrix Proteins; D005260:Female; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D009747:Nutritional Physiological Phenomena; D015675:Osteocalcin / Q000737:chemistry; D010024:Osteoporosis / Q000209:etiology* / Q000503:physiopathology; D014812:Vitamin K / Q000502:physiology*; D014813:Vitamin K Deficiency / Q000503:physiopathology; D000097568:Matrix Gla Protein
D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D015675:Osteocalcin; D014812:Vitamin K; D000097568:Matrix Gla Protein