The study looked at how calcium supplements affect the absorption of zinc and iron in teenagers aged 12-17. They found that calcium intake varied among the groups, but iron and zinc intake did not. Boys and girls had different absorption rates for calcium, iron, and zinc. Iron absorption was linked to puberty stage. Higher calcium intake (600-800mg/day) seemed to increase absorption rates of calcium, iron, and zinc in boys. However, at a higher calcium intake (1400mg/day), there was no significant effect on iron and zinc absorption in Chinese adolescents aged 12-17.