[Biological effects of vitamin K and concentration of vitamin K in Norwegian food].
BACKGROUND
Vitamin K has several biological effects and dietary intake seems to be more important than previously believed because of low bioavailability of the vitamins from the colon.


METHODS
Data from the literature were identified on PubMed, and data from NORKOST II (a dietary study from 1997 based on a nation-wide sample of respondents) were used to calculate dietary intake of vitamin K.


RESULTS
The dietary intake of vitamin K in Norway seems to be < 50% of what is recommended. The stores of vitamin K are small and T/2 in the body is approximately 1-1.5 day. Vitamin K executes its effects by carboxylation of proteins and as ligand (vitamin K2) for a nuclear transcription factor. Biological effects beyond coagulation include bone formation, neural functioning and blood vessel calcification. Anticoagulation with warfarin inhibits vitamin K-dependent reactions and may have detrimental effects on bone formation.


CONCLUSIONS
It is possible that the high incidence of osteoporosis in Norway may be due to the low dietary intake of vitamin K, hence it is suggested that the intake of vitamin K should be increased and vitamin K antagonists be replaced with specific thrombin inhibitors. New technology allows measurements of plasma concentration of vitamin K in relation to malabsorption, insufficient diet, and osteoporosis.
Drevon
Christian A
CA
Avdeling for ernaeringsvitenskap, Institutt for medisinske basalfag, Universitetet i Oslo, Postboks 1046 Blindern, 0316 Oslo. c.a.drevon@basalmed.uio.no
Henriksen
Hege Berg
HB
Sanderud
Marianne
M
Gundersen
Thomas E
TE
Blomhoff
Rune
R
D000328:Adult; D001777:Blood Coagulation / Q000187:drug effects / Q000502:physiology; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D002114:Calcinosis / Q000517:prevention & control; D002648:Child; D005260:Female; D005504:Food Analysis; D006801:Humans; D008297:Male; D009410:Nerve Degeneration; D009664:Norway; D009751:Nutritional Requirements; D010024:Osteoporosis / Q000209:etiology / Q000517:prevention & control; D014812:Vitamin K / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism / Q000502:physiology*
D014812:Vitamin K