Effect of Vitamin K(2) Alone or in Combination on Various Bone Turnover Markers Amongst Postmenopausal Females

BACKGROUND: Osteoporosis is common in postmenopausal women. Some studies have demonstrated the usefulness of vitamin K through the action of bone-specific proteins and osteoblast and osteoclast activities. However, no systematic review had explored this aspect in postmenopausal women. Hence, this systematic review aimed to explore the effect of vitamin K(2) alone or in combination with other agents (vitamin D(3) or calcium) on various bone turnover markers (BTMs) and bone mineral density (BMD) in postmenopausal women. METHODS: MEDLINE, ScienceDirect, PubMed, and Google Scholar were searched to identify relevant studies using specific inclusion criteria. Data extraction and quality assessment were carried out using standardized tests, and the results were narratively synthesized and presented in the form of tables. RESULTS: Vitamin K(2) was beneficial in inducing an improvement or preventing deterioration, as evidenced by the BMD and osteocalcin (OC), undercarboxylated OC (ucOC), carboxylated OC (cOC), and γ-carboxylated OC levels. However, its effect was not conclusive when procollagen type 1 N-terminal propeptide, carboxyterminal propeptide of type I procollagen, C-terminal telopeptide of type I collagen, bone alkaline phosphatase, deoxypyridinoline, and N-terminal telopeptide levels (NTX) and ucOC:cOC or cOC:ucOC, and NTX:creatinine ratios were examined. CONCLUSIONS: Vitamin K(2) supplementation combined with vitamin D and calcium was found to be advantageous. However, vitamin K(2) supplementation cannot replace the existing treatment options. In addition, vitamin K(2) should be used with caution, considering its interactions with food and other drugs.