The Selection and Prevalence of Natural and Fortified Calcium Food Sources in the Diets of Adolescent Girls

Objective: To assess the impact of calcium-fortified food and dairy food on selected nutrient intakes in the diets of adolescent girls. Design: Randomized controlled trial, secondary analysis. Setting and Participants: Adolescent girls (n = 149) from a midwestern metropolitan area participated in randomized controlled trials of bone physiology from 1997 to 2008. Intervention: Subjects randomly assigned to a high-calcium (HC) diet supplying 1,500 mg calcium/d, or their usual diet (UC). Main Outcome Measures: Dietary intake was assessed from 3-day food records and calcium intakes categorized by food source. Food group composites, representing calcium-fortified and dairy food categories, were examined for their relative nutrient contributions. Student t tests were used to evaluate differences in selected nutrient intakes between the 2 study groups. Results: Dairy food contributed 68% of the total mean 1,494 mg calcium/d in the HC group, and calcium-fortified food contributed 304 mg calcium. In the UC group, dairy food contributed 69% of the total mean 765 mg calcium/d and calcium-fortified food contributed 50 mg calcium. Nutrient profiles of the dairy composites differed significantly from the calcium-fortified composites (P < .05). Conclusions and Implications: Dairy food was the primary source of calcium selected by these adolescent girls; calcium-fortified food augmented calcium intakes.