[Vitamin D, K and bone mineral density].

Both vitamin D and vitamin K are essential nutrients for bone health. It is believed that vitamin D deficiency is responsible for rickets in infants and osteomalacia in adults, and chronic vitamin D insufficiency induces hyperparathyroidism and reduces bone mineral density, resulting in an increased risk of osteoporosis. Vitamin K deficiency is thought to cause impaired activation of bone matrix protein osteocalcin, and reduction of osteoblast function, resulting in impaired bone formation. Recently, we reported that a high prevalence of low vitamin D status (low serum 25-hydroxyvitamin D concentration) . low bone mineral density, and a high prevalence of low vitamin K status (high serum undercarboxylated osteocalcin concentration) . high frequency of bone fracture in elderly women in Japan. However, no correlation between low vitamin K status and low bone mineral density was observed in this subjects.