Osteocalcin undercarboxylated

Supplementation with high doses of vitamin K1 (1 mg/day for 14 days) or MK-4 (45 mg/day) resulted in decreased levels of undercarboxylated osteocalcin and increase of bone formation markers and in a significant reduction in bone loss, respectively. Using such high doses, any kind of effects besides vitamin K can not yet be ruled out and have to be further elucidated by long term studies. An overview can be found in a review by Palacios [4]. 

Undercarboxylated osteocalcine is probably a result of the lack of vitamin K, and it can be its indicator (S10). On the contrary, decrease in affinity of the undercarboxylated osteocalcine to apatite can explain the ability to predict bone fractures (V5). 

In deficiency, there is also undercarboxylated osteocalcin in the circulation, and this provides a more sensitive index of marginal status it is detectable, and responds to supplements of vitamin K, in subjects with normal clotting time and no circulating preprothrombin (Sokoll and Sadowski, 1996 Binkley et al., 2000). 

Most reference intakes are based on 0.5 to 1 /xg phylloquinone per kg of body weight (see Table 5.1). However, the U.S./Canadian Adequate Intake (Institute of Medicine, 2001) is 120 /xg for men and 90 /xg for women, based on observed intakes. There is some evidence that average intakes may, in fact, be inadequate to permit full carboxylation of osteocalcin Binkley and coworkers (2000) showed that giving supplements to normal healthy subjects reduced the circulating concentration of undercarboxylated osteocalcin. 

Sokoll LJ, O Brien ME, Camilo ME, Sadowski JA. Undercarboxylated osteocalcin and development of a method to determine vitamin K status. Clin Chem 1995 41 1121-8. 

BMD, bone mineral density ucOC, undercarboxylated osteocalcin. Data from Weber P (2001) Vitamin K and bone health. Nutrition 17 880-887, and S. Karger AG, Basel. 

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