The effect of dietary vitamin K2 (menaquinone-7, MK-7) and cheonggukjang (CGJ) on the prevention of ovariectomy (OVX)-induced bone loss was studied in rats. Female Sprague-Dawley rats were divided into eight groups: sham-operated; OVX control; OVX treated with MK-7 at doses of 2, 4, and 8 μg/day; and OVX treated with CGJ at doses of 0.063, 0.125, and 0.250 g/day referenced to MK-7 levels at 2, 4, and 8 μg/day, respectively. After 8 weeks of treatment, the preventive effects of MK-7 and CGJ were evaluated by measuring body weights, serum levels of bone turnover markers, bone mineral content (BMC), bone mineral density (BMD), trabecular microarchitectural properties, and bone histological characteristics. Our results showed that rats treated with a high dose of MK-7 (8 μg/day) exhibited a minor inhibitory effect on OVX-induced bone loss, as indicated by a significant increase in trabecular number, as well as BMC and BMD (P<.01). Moreover, the preventive effects of MK-7 were augmented by administration of CGJ at the same MK-7 dose. In addition, the preventive effects of CGJ were shown to be dose dependent, with the highest dose (0.250 g/day) significantly (P<.01) increasing BMC and BMD by 31.8% and 47.6%, respectively. In summary, these results suggest that administration of CGJ containing abundant levels of MK-7 may be a promising approach for the treatment and prevention of osteoporosis.
