Lately I’m seeing more patients taking high-dose vitamin D supplements (usually D3, aka cholecalciferol) rather than traditional 400–800 IU/day.
From a recent study:
This randomized trial compares the effects of 400 vs 4000 vs 10 000 IU of vitamin D on total volumetric bone mineral density and bone strength of the radius and tibia.
Among healthy adults, treatment with vitamin D for 3 years at a dose of 4000 IU per day or 10 000 IU per day, compared with 400 IU per day, resulted in statistically significant lower radial BMD; tibial BMD was significantly lower only with the 10 000 IU per day dose. There were no significant differences in bone strength at either the radius or tibia. These findings do not support a benefit of high-dose vitamin D supplementation for bone health; further research would be needed to determine whether it is harmful.
Steve Parker, M.D.