Vitamin K and bone health.
In the past decade it has become evident that vitamin K has a significant role to play in human health that is beyond its well-established function in blood clotting. There is a consistent line of evidence in human epidemiologic and intervention studies that clearly demonstrates that vitamin K can improve bone health. The human intervention studies have demonstrated that vitamin K can not only increase bone mineral density in osteoporotic people but also actually reduce fracture rates. Further, there is evidence in human intervention studies that vitamins K and D, a classic in bone metabolism, works synergistically on bone density. Most of these studies employed vitamin K(2) at rather high doses, a fact that has been criticized as a shortcoming of these studies. However, there is emerging evidence in human intervention studies that vitamin K(1) at a much lower dose may also benefit bone health, in particular when coadministered with vitamin D. Several mechanisms are suggested by which vitamin K can modulate bone metabolism. Besides the gamma-carboxylation of osteocalcin, a protein believed to be involved in bone mineralization, there is increasing evidence that vitamin K also positively affects calcium balance, a key mineral in bone metabolism. The Institute of Medicine recently has increased the dietary reference intakes of vitamin K to 90 microg/d for females and 120 microg/d for males, which is an increase of approximately 50% from previous recommendations.
Weber
P
P
Vitamins and Fine Chemicals Division, Human Nutrition & Health, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland. peter.weber@roche.com
D015519:Bone Density / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism*; D004357:Drug Synergism; D005260:Female; D050723:Fractures, Bone / Q000517:prevention & control*; D006801:Humans; D008297:Male; D009751:Nutritional Requirements; D015675:Osteocalcin / Q000097:blood / Q000378:metabolism; D010024:Osteoporosis / Q000517:prevention & control*; D014807:Vitamin D / Q000494:pharmacology / Q000627:therapeutic use; D014812:Vitamin K / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000627:therapeutic use
D015675:Osteocalcin; D014812:Vitamin K; D014807:Vitamin D