The Bone-Vasculature Axis: Calcium Supplementation and the Role of Vitamin K

Area of Science:

• Biochemistry
• Nephrology
• Endocrinology

Background:

• Calcium supplements are widely used for osteoporosis, often with vitamin D.
• The efficacy of calcium in reducing fracture risk remains uncertain.
• High-dose calcium intake poses cardiovascular risks, particularly for post-menopausal women and CKD patients.

Purpose of the Study:

• To review current literature on calcium supplementation in post-menopausal women and CKD patients.
• To discuss molecular mechanisms of vascular calcification.
• To explore the potential of vitamin K2 in mitigating adverse effects of calcium supplementation.

Main Methods:

• Literature review of studies on calcium supplementation, osteoporosis, CKD, and vascular calcification.
• Analysis of molecular mechanisms involving vitamin K-dependent proteins in calcium homeostasis.
• Discussion of therapeutic strategies involving vitamin K2.

Main Results:

• Calcium supplementation's role in fracture reduction is unclear.
• High calcium doses are linked to increased cardiovascular morbidity and mortality.
• CKD patients and calcium-based phosphate binders exacerbate vascular calcification risk.

Conclusions:

• Vitamin K-dependent pathways are crucial for calcium homeostasis.
• Vitamin K2 supplementation may prevent or slow vascular calcification caused by excessive calcium intake.
• Further research is needed to establish vitamin K2 as a therapeutic strategy.