High-dose vitamin D may harm bone health

Doses at or above 4000 IU/day lowered volumetric bone density: study
Reuters Health
Bone density

Higher doses of vitamin D in healthy adults who aren’t vitamin D deficient don’t improve bone health and may actually be harmful, according to a Canadian trial.

The randomised controlled trial in JAMA assessed the effect of vitamin D supplementation on volumetric bone mineral density and strength in 311 healthy adults (53 men; mean age 62) without osteoporosis.