Calcium requirements during adolescence to maximize bone health

The calcium requirements of boys and girls during adolescence have largely been based on balance studies, including more recently the use of stable nu clides. Bone measurements by dual energy X-ray absorptiometry (DXA) and sim ilar instruments have provided an end-point by which to assess skeletal dev elopment, either of the entire skeleton or of specific bones, in relation t o the consumption of calcium and other nutrients and to physical activity. Several cross-sectional studies, using measurements of bone mineral density (BMD) and bone mineral content (BMC), suggest that optimal calcium intakes for female adolescents may be somewhat lower than published as the Adequat e Intakes (AIs) by the Institute of Medicine in 1997, but they may be somew hat higher for adolescent males. These results suggest that gander should b e considered in establishing recommendations for calcium. In addition, othe r studies have provided evidence that prepubertal and postpubertal skeletal growth of males and females is enhanced by regular physical activities and that the optimal attainment of BMC and BMD by females by late adolescence may not be dependent on such a high calcium intake as previously thought, a lthough males may need at least the recommended amount. Therefore, physical activity should also be considered in establishing recommendations for cal cium. In summary, two lines of evidence suggest that more extensive informa tion on diet and lifestyle should be considered in the future for making mo re specific recommendations on calcium intakes for optimal skeletal develop ment for prepubertal and postpubertal boys and girls.