Vitamin K Impacts Bone, Body Composition

TOKYOAccording to results of a recent animal trial, long-term supplementation with either vitamin K1 (phylloquinone) or vitamin K2 (menaquinone-4) can improve certain parameters associated with bone strength, as well as improve body composition by decreasing fat accumulation. Researchers from Komazawa Women's University and Japan Women's University, both in Tokyo, published their findings Feb. 1, online ahead of print in the journal Bone.

In the study, 23 female Sprague-Dawley strain rats (six weeks old) were given either a basic control diet group, a vitamin K1-rich diet (600mg/kg diet) or vitamin K2-rich diet (600mg/kg diet) for three months and monitored for bone mineral density (BMD), bone strength, body composition and serum parameters. After three months, rats in the K1 group showed significantly increased femur BMD, compared to the control die. While K2 supplementation showed no such effect on BMD compared to controls, the vitamin did improve two bone strength parameters, minimum cross-sectional moment of inertia and the polar moment of inertia, compared to controls. Further, compared to controls, rats in the K2 group also showed significantly increased femoral bone parameters, including width, dry weight and ash weight, and cortical, cancellous, trabecular, and total bone mineral contents. Scientists noted the addition of both K1 and K2 to the control diet led to significantly decreased fat accumulation; also,  serum triglycerides were decreased by 48 percent in the K1 group and by 29 percent in the K2 group, compared to controls. There were no significant differences in the levels of serum calcium, phosphorus, alkaline phosphatase, growth hormone, insulin-like growth hormone-1, insulin-like growth hormone binding protein-3, and cross-linked N-teleopeptide of type I collagen among the three groups.

The researchers noted, Tthis is the first study to demonstrate the effect of the long-term addition of K1 or K2 to the control diet on body composition and serum parameters in an in vivo system using rats. They suggested additional studies on the mechanism of vitamin K supplementation in the regulation of bone metabolism would provide valuable data on the prevention of lifestyle-related disorders, including osteoporosis.