2000 IU vitamin D not enough to get most Chinese to 20 ng level – RCT Feb 2015

But 800 IU was enough to get most to 12 ng

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

Eur J Nutr. 2015 Feb 19. [Epub ahead of print]
Yao P1, Lu L, Hu Y, Liu G, Chen X, Sun L, Ye X, Zheng H, Chen Y, Hu FB, Li H, Lin X.

PURPOSE:
To determine the dose-response of vitamin D3 supplementation on serum 25-hydroxyvitamin D [25(OH)D] among Chinese adults.

METHODS:
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.

RESULTS:
The mean (SD) serum 25(OH)D at baseline was 31.6 (8.7) nmol/L, and the dose-response relationship was curvilinear with a plateau around 6 weeks for all doses. At week 16, 25(OH)D was increased by 6.0 (6.5), 21.7 (15.8), 26.3 (12.6), 32.0 (12.8) and 36.3 (26.0) nmol/L for 0, 400, 800, 1200 and 2000 IU/d (all P ≤ 0.002), corresponding to approximately 19, 53, 67, 77 and 80 % of reversion of vitamin D deficiency, respectively.
Daily intake of 800 IU vitamin D3 reached a targeted 25(OH)D ≥ 30 nmol/L in at least 97.5 % of Chinese, but not a targeted 25(OH)D ≥ 50 nmol/L even with 2000 IU/d. Change of 25(OH)D was inversely associated with change of PTH concentration (r = -0.39, P < 0.001) after controlling for age and sex. No between-group differences were observed in terms of the change in serum calcium, alanine transaminase, aspartate aminotransferase, gamma-glutamyltransferase and creatinine (P ≥ 0.22).

CONCLUSIONS:
Supplementation with 400, 800, 1200 or 2000 IU/d vitamin D could improve the vitamin D deficiency with various degrees. Whether 2000 IU/d vitamin D3 would generate a better result without side effect requires more studies with larger samples in future.

PMID: 25694350 DOI: 10.1007/s00394-015-0859-4 publisher wants $40 for the PDF

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