Do vitamin D supplements protect bones? A large meta-analysis

What does the research say?

In adults who were not deficient, vitamin D supplements on their own did not prevent fractures or falls, or meaningfully improve bone density. That doesn’t mean vitamin D is unimportant: it suggests extra supplements add little once levels are adequate.

The science

The review pooled randomised trials testing vitamin D (mostly without calcium) on fractures, falls and bone mineral density in adults.

Vitamin D did not reduce total fractures, hip fractures or falls, and differences in bone density were too small to matter clinically, whether high or low doses were used.

Key findings

• No reduction in total or hip fractures.
• No reduction in falls.
• No clinically meaningful change in bone density.

Limitations

• Most participants were not vitamin D deficient.
• Many trials tested vitamin D without calcium.
• It does not change UK advice: everyone should consider 10 µg (400 IU) a day in autumn and winter, and people at risk of deficiency year-round.

References

1. Bolland MJ, Grey A, Avenell A. Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. Lancet Diabetes Endocrinol. 2018;6(11):847–858. doi.org/10.1016/S2213-8587(18)30265-1