Merck
CN

Vitamin K intake and status are low in hemodialysis patients.

Kidney international (2012-06-01)
Ellen C M Cranenburg, Leon J Schurgers, Herma H Uiterwijk, Joline W J Beulens, Gerdien W Dalmeijer, Ralf Westerhuis, Elke J Magdeleyns, Marjolein Herfs, Cees Vermeer, Gozewijn D Laverman
ABSTRACT

Vitamin K is essential for the activity of γ-carboxyglutamate (Gla)-proteins including matrix Gla28 protein and osteocalcin; an inhibitor of vascular calcification and a bone matrix protein, respectively. Insufficient vitamin K intake leads to the production of non-carboxylated, inactive proteins and this could contribute to the high risk of vascular calcification in hemodialysis patients. To help resolve this, we measured vitamin K(1) and K(2) intake (4-day food record), and the vitamin K status in 40 hemodialysis patients. The intake was low in these patients (median 140 μg/day), especially on days of dialysis and the weekend as compared to intakes reported in a reference population of healthy adults (mean K(1) and K(2) intake 200 μg/day and 31 μg/day, respectively). Non-carboxylated bone and coagulation proteins were found to be elevated in 33 hemodialysis patients, indicating subclinical hepatic vitamin K deficiency. Additionally, very high non-carboxylated matrix Gla28 protein levels, endemic to all patients, suggest vascular vitamin K deficiency. Thus, compared to healthy individuals, hemodialysis patients have a poor overall vitamin K status due to low intake. A randomized controlled trial is needed to test whether vitamin K supplementation reduces the risk of arterial calcification and mortality in hemodialysis patients.

MATERIALS
Product Number
Brand
Product Description

Supelco
Phylloquinone (K1), analytical standard
Sigma-Aldrich
Vitamin K1, BioXtra, ≥99.0% (sum of isomers, HPLC), mixture of isomers
Sigma-Aldrich
Vitamin K1, viscous liquid
Phytomenadione, European Pharmacopoeia (EP) Reference Standard
Supelco
Phytonadione, Pharmaceutical Secondary Standard; Certified Reference Material