Meeting adequate intake for dietary calcium without dairy foods in adolescents aged 9 to 18 years (National Health and Nutrition Examination Survey 2001-2002)

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.