Journal of Bone and Mineral Metabolism

, Volume 17, Issue 1, pp 23–29

Effect of vitamin K2 (menaquinone-7) in fermented soybean (natto) on bone loss in ovariectomized rats

Authors

  • Masayoshi Yamaguchi
    • Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
  • Hideaki Taguchi
    • Nakano Central Research Institute, Nakano Vinegar Co., Ltd., 2-6 Nakamura-cho, Handa, Aichi 475-8585, Japan
  • Ying Hua Gao
    • Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
  • Aki Igarashi
    • Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
  • Yoshinori Tsukamoto
    • Nakano Central Research Institute, Nakano Vinegar Co., Ltd., 2-6 Nakamura-cho, Handa, Aichi 475-8585, Japan

DOI: 10.1007/s007740050059

Cite this article as:
Yamaguchi, M., Taguchi, H., Gao, Y. et al. J Bone Miner Metab (1999) 17: 23. doi:10.1007/s007740050059

Abstract:

The effect of dietary vitamin K2 (menaquinone-7) on bone loss in ovariectomized (OVX) rats was investigated. OVX rats were freely given experimental diets containing menaquinone-4 (MK-4; 12 mg/100 g diet) or menaquinone-7 (MK-7; 18.1 mg/100 g diet) for 24 days; MK-4 and MK-7 were equal in molar concentrations. This feeding caused a remarkable increase of MK-4 and MK-7 concentrations in the serum and femur of OVX rats. OVX-induced decrease in the femoral dry weight and femoral calcium content was prevented by the feeding of dietary MK-4 or NK-7. In separate experiments, OVX rats were freely given experimental diets containing the fermented soybean (natto; including 9.4 μg MK-7/100 g diet) without or with added MK-7 (37.6 μg/100 g diet) for 77 days. Feeding produced a significant elevation of MK-4 and MK-7 concentrations in the serum of OVX rats. In this case, a significant increase in the femoral MK-4 content was observed but MK-7 was not detected in the femoral tissues. OVX-induced decreases in the femoral dry weight and femoral calcium content were significantly prevented by the feeding of diets containing natto with MK-7 added (37.6 μg/100 g diets). This study demonstrates that the intake of dietary MK-7 has a preventive effect on bone loss caused by OVX. This effect may be partly caused by MK-4, which is formed by degradation of MK-7.

Key words: Vitamin K2menaquinone-4menaquinone-7bone metabolismovariectomyosteoporosis
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© Springer-Verlag Tokyo 1999