title: Vitamin K status in healthy volunteers.
abstract: Vitamin K's recommended dietary allowance (RDA) is based on the hepatic requirement for clotting factor synthesis, but substantial concentrations of undercarboxylated extra-hepatic Gla-proteins are found in the circulation of non-supplemented individuals. This suggests that vitamin K intake above the RDA is required for an optimal extra-hepatic vitamin K status. Circulating uncarboxylated osteocalcin (ucOC) and desphospho-uncarboxylated matrix Gla-protein (dp-ucMGP) are considered markers of the vitamin K status in bone and the vasculature, respectively. We measured these markers in 896 samples of healthy volunteers and defined target groups for vitamin K supplementation based on increased levels indicative of tissue-specific vitamin K deficiency. We studied the response to vitamin K supplements at different states of vitamin K deficiency by measuring the circulating dp-ucMGP level in samples from two short-term trials on menaquinone-7 (MK-7, vitamin K2) supplementation in 42 children and 68 adults. Children had high ucOC levels (3.4-96.9 ng ml(-1)); other age groups had values in the range of 1.5-5.0 ng ml(-1). From the age of 40 years, dp-ucMGP levels gradually increased. Children and adults with more pronounced vitamin K deficiency gave the highest responses to MK-7 supplementation. Children and adults above 40 years showed the largest tissue-specific vitamin deficiency and accordingly may benefit from MK-7 supplementation to improve their extra-hepatic vitamin K status.
authors.affiliation: VitaK, Maastricht University, Oxfordlaan 70, 6229 EV Maastricht, The Netherlands. e.theuwissen@vitak.com.
authors.forename: E
authors.initials: E
authors.lastname: Theuwissen
authors.forename: E J
authors.initials: EJ
authors.lastname: Magdeleyns
authors.forename: L A J L M
authors.initials: LA
authors.lastname: Braam
authors.forename: K J
authors.initials: KJ
authors.lastname: Teunissen
authors.forename: M H
authors.initials: MH
authors.lastname: Knapen
authors.forename: I A G
authors.initials: IA
authors.lastname: Binnekamp
authors.forename: M J H
authors.initials: MJ
authors.lastname: van Summeren
authors.forename: C
authors.initials: C
authors.lastname: Vermeer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002135:Calcium-Binding Proteins / Q000097:blood; D002648:Child; D002675:Child, Preschool; D019587:Dietary Supplements / Q000032:analysis; D016326:Extracellular Matrix Proteins / Q000097:blood; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D014812:Vitamin K / Q000008:administration & dosage* / Q000097:blood*; D014813:Vitamin K Deficiency / Q000097:blood / Q000188:drug therapy*; D055815:Young Adult; D000097568:Matrix Gla Protein
chemical_list: D015415:Biomarkers; D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D015675:Osteocalcin; D014812:Vitamin K; D000097568:Matrix Gla Protein