Food and Function., 2014, Advance Article, DOI: 10.1039/C3FO60464K
E. Theuwissen,*a E. J. Magdeleyns,a L. A. J. L. M. Braam,a K. J. Teunissen,a M. H. Knapen,a I. A. G. Binnekamp,b M. J. H. van Summeren b and C. Vermeer a
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.