High-dose vitamin D may harm bone health
Doses at or above 4000 IU/day lowered volumetric bone density: study
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.
They had baseline 25-hydroxyvitamin D levels of 30-125nmol/L. For three years, participants took daily doses of vitamin D3 of 400 IU, 4000 IU or 10,000 IU.
Calcium supplements were provided to those with dietary intake of less than 1200mg/day.
