Higher vitamin D intake is needed to achieve serum 25(OH)D levels greater than 50?nmol/l in Québec youth at high risk of obesity.
Eur J Clin Nutr. 2011 Mar 2.
Mark S, Lambert M, Delvin EE, O'Loughlin J, Tremblay A, Gray-Donald K.
School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, Canada.
Background/Objectives:Vitamin D levels are often observed to be low in Canadian youth, despite the mandatory fortification of fluid milk. We identified modifiable correlates of plasma vitamin D concentrations to inform public health efforts to remediate low-vitamin D status.
Subjects/Methods:We recruited 159 children aged 8-11 years, who were at at high risk of obesity, non-systematically during different seasons. Vitamin D status was assessed by measuring plasma 25-hydroxyvitamin D (25(OH)D) using a radioimmunoassay. Dietary intake, including vitamin supplements, was measured using three dietitian-administered 24?h diet recalls. Fat mass was measured by dual energy X-ray absorptiometry. Accelerometers were worn for 7 days to estimate physical activity. Independent correlates of plasma 25(OH)D concentrations were identified using multiple regression in an analysis controlling for season of measurement.
Results:Approximately, 7% of youth had hypovitaminosis D (25(OH)D 37.5?nmol/l) during winter and spring when vitamin D levels are at their nadir. Only 55% of participants had vitamin D levels, which the Institute of Medicine considers optimal (25(OH)D >50?nmol/l). The mean dietary vitamin D intake, 6.6?mcg, was well below current recommendations set at 15?mcg. A serving increase in milk consumption and a s.d. increase in physical activity were associated with only a 2.9 and 2.1?nmol/l increase in plasma 25(OH)D, respectively. There was no association between 25(OH)D and adiposity.
Conclusions:Our results indicate the challenges of obtaining adequate vitamin D intake from the current food supply to support a level of 25(OD)D >50?nmol/l.
European Journal of Clinical Nutrition advance online publication, 2 March 2011; doi:10.1038/ejcn.2011.5. PMID: 21364606
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- 55% > 20 ng
- 7% < 15 ng
- Extra milk add 1.1 ng
- Extra movement add 0.84 ng