Menaquinone-7 lowers undercarboxylated osteocalcin, ups adiponectin in postmenopausal women

In healthy postmenopausal women, treatment with menaquinone-7 (MK-7) for 12 months leads to the reduction of undercarboxylated osteocalcin (ucOC) and the elevation of adiponectin, a recent study has found. In contrast, MK-7 exerts no notable effect on insulin resistance.

Researchers conducted a randomized, placebo-controlled trial including 148 healthy postmenopausal women who were given either 375 µg of MKL-7 daily (n=71) or placebo (n=71), as an add-on to 800-g calcium and 38-µg vitamin D. Intervention lasted for 12 months. Outcomes included serum ucOC, insulin resistance (via the homeostasis model assessment of insulin resistance [HOMA-IR]), and plasma adiponectin and leptin.

At the 12-month follow-up, women in the MK-7 arm showed a significant reduction in median serum ucOC (–70.3 percent; p<0.01). No such change was reported in placebo comparators (median, –7.2 percent; p=0.12). The resulting between-group difference was significant (p<0.001).

Similarly, OC and the ratio ucOC/OC were significantly reduced in the MK-7 arm at 12 months (p<0.05 for both), while placebo participants showed no changes. Differences between groups were likewise significant (p<0.001 for both).

Along with the reduction in ucOC, the researchers recorded a significant increase in mean plasma adiponectin at 12 months in the MK-7 (6.1±20.1 percent; p=0.01), but not in the placebo group (–0.7±15.5 percent; p=0.49; between-group difference p=0.03).

In contrast, HOMA-IR, serum insulin, plasma leptin, glycated haemoglobin, and markers of inflammation did not differ between groups.

“We found no effect of MK-7 on insulin resistance but suggest that the effects of MK-7 on glucose metabolism should be further investigated in populations more prone to diabetes,” the researchers said.