Vitamin K status in healthy volunteers

Food Funct. 2014 Feb;5(2):229-34. doi: 10.1039/c3fo60464k.

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.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Calcium-Binding Proteins / blood
  • Child
  • Child, Preschool
  • Dietary Supplements / analysis
  • Extracellular Matrix Proteins / blood
  • Female
  • Healthy Volunteers
  • Humans
  • Male
  • Middle Aged
  • Osteocalcin / blood
  • Vitamin K / administration & dosage*
  • Vitamin K / blood*
  • Vitamin K Deficiency / blood
  • Vitamin K Deficiency / drug therapy*
  • Young Adult

Substances

  • Biomarkers
  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • matrix Gla protein
  • Osteocalcin
  • Vitamin K