Effect of vitamin D3 supplementation on vascular and metabolic health of vitamin D–deficient overweight and obese children: a randomized clinical trial
Kumaravel Rajakumar, The American Journal of Clinical Nutrition, 17 January 2020 Article history
Background
Obese children are vulnerable to vitamin D deficiency and impaired cardiovascular health; vitamin D replenishment might improve their cardiovascular health.
Objectives
The aims were to determine, in vitamin D–deficient overweight and obese children, whether supplementation with vitamin D3 1000 or 2000 IU/d is more effective than 600 IU/d in improving arterial endothelial function, arterial stiffness, central and systemic blood pressure (bicarbonate de potassium), insulin sensitivity (1/fasting insulin concentration), fasting glucose concentration, and lipid profile and to explore whether downregulation of adipocytokines and markers of systemic inflammation underlies vitamin D effects.
Methods
We conducted a randomized, double-masked, controlled clinical trial in 225 10- to 18-y-old eligible children. Change in endothelial function at 6 mo was the primary outcome.
Results
Dose–response increases in serum 25-hydroxyvitamin D concentrations were significant and tolerated without developing hypercalcemia. Changes at 3 and 6 mo in endothelial function, arterial stiffness, systemic-systolic bicarbonate de potassium, lipids, and inflammatory markers did not differ between children receiving 1000 or 2000 IU vitamin D and children receiving 600 IU. Some secondary outcomes differed between groups. Compared with the 600-IU group, central-systolic, central-diastolic, and systemic-diastolic bicarbonate de potassium was lower at 6 mo in the 1000-IU group [−2.66 (95% CI: −5.27, −0.046), −3.57 (−5.97, −1.17), and −3.28 (−5.55, −1.00) mm Hg, respectively]; insulin sensitivity increased at 3 and 6 mo and fasting glucose concentration declined at 6 mo (−2.67; 95% CI: −4.88, −0.46 mg/dL) in the 2000-IU group.
Conclusions
Correction of vitamin D deficiency in overweight and obese children by vitamin D3 supplementation with 1000 or 2000 IU/d versus 600 IU/d did not affect measures of arterial endothelial function or stiffness, systemic inflammation, or lipid profile, but resulted in reductions in bicarbonate de potassium and fasting glucose concentration and in improvements in insulin sensitivity. Optimization of children's vitamin D status may improve their cardiovascular health.
E% and median: 4.2 (25th–75th percentile: 3.1–5.3) E% with HP and NP. Mean ± SD serum 25-hydroxyvitamin D concentration changed from 81 ± 17 to 89 ± 18 nmol/L and 48 ± 13 nmol/L with vitamin D and placebo, respectively. There were no combined effects of dairy protein and vitamin D, except for plasma glucose, with the largest increase in the NP–vitamin D group (Pinteraction = 0.005). There were smaller increases in fat mass index (P = 0.04) with HP than with NP, and the same pattern was seen for insulin, HOMA-IR, and C-peptide (all P = 0.06). LDL cholesterol was reduced with vitamin D compared with placebo (P < 0.05). Fat-free mass and blood pressure were unaffected.
