The effect of vitamin K supplementation on circulating osteocalcin (bone Gla protein) and urinary calcium excretion

Ann Intern Med. 1989 Dec 15;111(12):1001-5. doi: 10.7326/0003-4819-111-12-1001.


Study objective: To determine whether vitamin K administration affects urinary calcium excretion in postmenopausal women.

Design: Before- and after-trials with a 2-week treatment period.

Subjects: Healthy postmenopausal women (55 to 75 years old) were recruited from the convents in and around Maastricht. Controls (25 to 40 years old) were healthy premenopausal volunteers.

Intervention: Daily administration of 1 mg of vitamin K for 2 weeks.

Measurements: Serum immunoreactive osteocalcin: hydroxylapatite binding (HAB) capacity of serum immunoreactive osteocalcin; excretion of calcium, hydroxyproline, and creatinine in the urine during the last 2 h of a 16-h fasting period.

Results: In premenopausal women, no effect of vitamin K administration was seen. In the postmenopausal group, vitamin K induced increased serum immunoreactive osteocalcin concentration; normalization of the HAB capacity of serum immunoreactive osteocalcin (this marker was less than 50% that of the controls in the pretreatment samples); a decrease in urinary calcium excretion, notably in the "fast losers" of calcium; and a parallel decrease in urinary hydroxyproline excretion in the fast losers of calcium.

Conclusions: The serum immunoreactive osteocalcin level may vary with vitamin K status. This variance should be taken into consideration if osteocalcin is used as a marker for osteoblast activity. Vitamin K is one factor that may play a role in the loss of bone mass in postmenopausal osteoporosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Calcium / urine*
  • Data Interpretation, Statistical
  • Durapatite
  • Female
  • Humans
  • Hydroxyapatites
  • Hydroxyproline / urine
  • Menopause / blood
  • Menopause / urine
  • Middle Aged
  • Osteocalcin / blood
  • Osteocalcin / drug effects*
  • Protein Binding
  • Radioimmunoassay
  • Vitamin K / pharmacology*


  • Hydroxyapatites
  • Osteocalcin
  • Vitamin K
  • Durapatite
  • Hydroxyproline
  • Calcium