British Journal of Nutrition

Research Article

Effect of phylloquinone supplementation on biochemical markers of vitamin K status and bone turnover in postmenopausal women

Susanne Bügela1 c1, A. Dorthe Sørensena1, Ole Helsa1, Mette Kristensena1, Cees Vermeera2, Jette Jakobsena3, Albert Flynna4, Christian Mølgaarda1 and Kevin D. Cashmana4

a1 Department of Human Nutrition/Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark

a2 Department of Biochemistry, University of Maastricht, Maastricht, The Netherlands

a3 Danish Institute for Food and Veterinary Research, Søborg, Denmark

a4 Department of Food and Nutritional Sciences, University College Cork, Cork, Republic of Ireland

Abstract

While current intakes of phylloquinone (vitamin K1) in many populations are believed to be sufficient to maintain normal blood coagulation, these may be insufficient to cover the requirements for optimal bone metabolism. Therefore, the objective of the present study was to investigate the effect of increasing phylloquinone intakes above the usual dietary intake for 6 weeks on biochemical markers of vitamin K status and bone turnover in postmenopausal women. Thirty-one postmenopausal women completed this 3 × 6-week randomised cross-over study, in which volunteers were supplemented with 0 (placebo), 200, and 500 μg phylloquinone/d. In addition, the volunteers were given 10 μg vitamin D3/d throughout the study period. With increasing phylloquinone intake, the concentration of serum γ-carboxylated and under-γ-carboxylated osteocalcin was significantly increased and decreased, respectively, in a dose-dependent manner (P < 0·001). Mean serum phylloquinone concentration was significantly (P < 0·001) higher with daily supplementation with 500 μg phylloquinone/d compared with that during either of the placebo or 200 μg phylloquinone/d supplementation periods, which did not differ (P = 0·15). Serum total osteocalcin was significantly (P < 0·001) increased in response to daily supplementation with 500 (but not 200) μg phylloquinone compared with placebo. Serum bone-specific alkaline phosphatase as well as the urinary markers of bone resorption (N-telopeptide cross-links of collagen, pyridinoline and deoxypyridinoline) and urinary γ-carboxyglutamate were unaffected by phylloquinone supplementation. In conclusion, while daily supplementation with 200 and 500 μg phylloquinone/d for 6 weeks increased vitamin K status in postmenopausal women, it had no effect on bone turnover.

(Received December 13 2005)

(Revised April 11 2006)

(Accepted April 24 2006)

Footnotes

Abbreviations: BAP, bone-specific alkaline phosphatase; BMD, bone mineral density; cOC, γ-carboxylated osteocalcin; Dpyr, deoxypyridinoline; Gla, γ-carboxyglutamate; NTx, type I collagen cross-linked N-telopeptides; 25(OH)D, 25-hydroxyvitamin D; 1,25(OH)2D, 1,25-dihydroxyvitamin D; Pyr, pyridinoline; tOC, total osteocalcin; ucOC, under-γ-carboxylated osteocalcin

0Comments