Background: In the United States, >50% of dietary calcium is provided by milk and milk products. Calcium intakes in the United States are inadequate for many children, and a large proportion do not drink milk or consume dairy products. However, no studies have addressed whether dairy-free diets can provide adequate calcium while meeting other nutrient recommendations.
Objective: To determine the highest calcium intake for adolescents obtained from dairy-free diets, and to examine the relationship between intakes of calcium-fortified foods, using citrus juice as an example, and maximal calcium intakes.
Design: In the National Health and Nutrition Examination Survey 2001 to 2002, 65 females and 62 males, aged 9 to 18 years, reported no intake of dairy. We used linear programming to generate diets with maximal calcium intake, while meeting Dietary Reference Intakes for a set of nutrients, limiting energy and fat intakes, and not selecting food quantities exceeding amounts usually eaten in the population.
Results: With food use and energy and fat constraints, diets formulated by linear programming provided 1,150 and 1,411 mg/day of calcium for girls and boys, respectively. With the Dietary Reference Intakes constraints, these decreased to 869 and 1,160 mg/day. When we introduced 1.5 servings of fortified juice to the diets, the highest calcium intake increased to 1,302 mg/day for girls and to 1,640 mg/day for boys.
Conclusions: Adequate intake for calcium cannot be met with dairy-free diets while meeting other nutrient recommendations. To meet the adequate intake for calcium without large changes in dietary patterns, calcium-fortified foods are needed. In addition, greater physical activity and responsible sunlight exposure should be encouraged to promote vitamin D adequacy.