Evidence Level
Strong
Calcium supplementation has a large evidence base, primarily for bone health. The Women's Health Initiative (Jackson et al., 2006, n=36,282) demonstrated that calcium + vitamin D reduced hip fracture risk in adherent participants. However, a 2015 BMJ meta-analysis by Bolland et al. raised concerns about potential cardiovascular risks with calcium supplements exceeding 1,000mg/day, though this remains debated. Current consensus from the National Osteoporosis Foundation supports supplementation to reach 1,000-1,200mg total daily intake when dietary intake is insufficient, always paired with vitamin D.