A dose–response study of vitamin D3 supplementation in healthy Chinese: a 5-arm randomized, placebo-controlled trial

To determine the dose–response of vitamin D3 supplementation on serum 25-hydroxyvitamin D [25(OH)D] among Chinese adults. In this 5-arm, randomized, double-blinded controlled trial, 76 healthy participants were assigned to orally administrate 0, 400, 800, 1200 or 2000 IU/d of vitamin D3 for 16 weeks. Serum 25(OH)D, parathyroid hormone, calcium, biomarkers of liver and renal function were measured at multiple time points. The mean (SD) serum...