but not increased fractional calcium absorption, in 4–8-y-old children: a double-blind randomized controlled trial 1,2,3,4
Am J Clin Nutr January 2013 vol. 97 no. 1 217-223
Steven A Abrams, Keli M Hawthorne, and Zhensheng Chen
1 From the USDA/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX.
↵2 The contents of this publication do not necessarily reflect the views or policies of the USDA, nor does mention of trade names, commercial products, or organizations imply endorsement by the US government.
↵3 Supported in part by the USDA/ARS under Cooperative Agreement no. 58-6250-6-001, NCRR General Clinical Research for Children Grant no. RR00188, NIH AR43740.
↵4 Address correspondence to SA Abrams, USDA/ARS Children's Nutrition Research Center, 1100 Bates Street, Houston, TX 77030. E-mail: sabrams at bcm.edu.
Background: The effects of vitamin D supplementation in healthy prepubertal children on physiologic outcomes have not been investigated.
Objective: The objective was to evaluate the effects of supplementation with 1000 IU vitamin D3/d on calcium absorption.
Design: In a double-blind, placebo-controlled trial, we randomly assigned 64 children to 1000 IU vitamin D3/d (n = 32) or placebo (n = 32) for 8 wk. Stable isotopes were used to assess calcium absorption. The main outcome measure was calcium absorption before and after supplementation.
Results: All of the data are shown as means ± SDs. At baseline, vitamin D intake was 221 ± 79 IU/d and calcium intake was 830 ± 197 mg/d. Baseline serum 25-hydroxyvitamin D [25(OH)D] was not significantly correlated with fractional or total calcium absorption. After 8 wk, with baseline values used as a covariate, no differences were seen in fractional or total calcium absorption based on supplementation group (P = 0.75 and 0.36, respectively).
Supplemented children had a significant increase in 25(OH)D concentrations (from 27.7 ± 7.4 to 36.0 ± 10.3 ng/mL; P < 0.0001) and a decrease in parathyroid hormone (from 21.4 ± 10.4 to 12.9 ± 7.1 pg/mL; P < 0.001); no significant changes in the placebo group were observed. No adverse side effects were noted in either group.
Conclusions: Vitamin D3 supplementation at 1000 IU/d increases 25(OH)D and decreases parathyroid hormone in children with average vitamin D intakes below the dietary recommendations of the Institute of Medicine. However, no significant effects of this change on calcium absorption occurred. This trial was registered at clinicaltrials.gov as NCT 00868738.