Effect of menatetrenone (vitamin K2) treatment on bone loss in patients with anorexia nervosa.

Osteoporosis is a common complication of anorexia nervosa (AN). Although weight recovery and resumption of menses are important goals in AN treatment, they are often achieved only after a prolonged period of recovery. Therefore, it becomes important to find therapies with the potential to prevent further decreases in bone mineral density (BMD). We conducted a non-randomized study of the effects of menatetrenone (vitamin K2) on bone loss in patients with AN. Lumbar BMD was longitudinally measured by Dual Energy X-ray Absorptiometry (DXA) in 10 patients with AN who chose to receive menatetrenone treatment (MED+ group) and 11 patients who did not (MED- group). During the mean 0.9-year follow-up period, the BMD of the lumbar vertebrae of the MED+ group decreased significantly less than that of the MED- group (-2.8% and -6.9%, respectively). Among bone metabolism markers, gamma-carboxyglutamic acid osteocalcin significantly increased (128.6% and 28.3%, respectively) and urine deoxypyridinoline significantly decreased (-44.5% and -13.7%, respectively) more in the MED+ group than in the MED- group. These differences in BMD and bone metabolism markers may be attributable to menatetrenone treatment. The results suggest that menatetrenone may be beneficial in the prevention of bone loss in patients with AN. Randomized placebo-controlled studies are needed to confirm these findings.