[Prevention of osteoporosis by foods and dietary supplements. "Kinnotsubu honegenki": a fermented soybean (natto) with reinforced vitamin K2 (menaquinone-7)].

In recent years, it has been proven that vitamin K(2) has important roles not only in blood coagulation but also in bone metabolism. We developed a Bacillus subtilis (natto) strain with high productivity of vitamin K(2) (Menaquinone-7), and commercialized a natto with reinforced vitamin K(2) by use of the strain. The natto, named "Kinnotsubu honegenki", was granted a health claim based on our clinical studies which demonstrated that intake of the natto stimulated gamma-carboxylation of osteocalcin.