Vitamin D vs Calcium

for bone health

Stronger evidence: tie

Stronger effect: tie

Safety: Vitamin D carries a minor interaction; Calcium has none recorded.

For bone health, the two are evidence-matched; the difference is in effect and safety.

grade B moderate certainty

supports bone density and reduces fracture risk with calcium, mainly in deficiency

800–2000 IU/day, older / deficient adults

grade B moderate certainty

modestly reduces fracture risk when combined with vitamin D, mainly in deficient/institutionalized populations

1000–1200 mg/day (with vitamin D), older adults

sources: PMID:20000104 · PMID:10000011