12～17岁少年钙代谢实验研究

目的通过钙代谢平衡实验探讨中国青春期少年的钙参考摄入量。方法从320名参与1年补钙实验4组12～17岁的少年中,每组随机抽取男、女生各10人,共80人。采用钙代谢平衡实验的方法。实验期共10d,膳食适应3d后,开始7d的代谢试验。收集研究对象试验期内摄入的食品、排出的粪便和尿液样品,用电感耦合等离子体发射光谱法测定样品中的钙含量。结果不同水平钙摄入组间的钙吸收量、粪钙排出量、钙储留量存在差异。钙表观吸收率女生平均为46.4%,男生68.7%。进行曲线拟合后,男生钙吸收率最高时的钙摄入量为665mg/d,女生钙吸收率达到平台时的钙摄入量为650mg。为了达到每日最大储留量,男生钙摄入量要达到545mg/d,女生要达到1055mg/d。结论中国12～17岁男生和女生的钙适宜摄入量有很大差别,男生钙适宜摄入量约为600～700mg/d,女生为1000～1100mg/d。

STUDY ON CALCIUM METABLISM AMONG 12-17 YEARS OLD ADOLESCENTS

Objective: To provide information for calcium DRI (dietary reference intakes) of Chinese adolescents by using calcium balance study. Method: Eighty students (12-17 years old) were selected randomly from 320 subjects who had calcium supplementation for 1 year. Ten boys and ten girls were randomly selected from each calcium supplement group to take part in the 10 d balance study. Subjects were given the representative diets during 3 d adaptation period and 7 d metabolism period. Samples of foods, feces and urine were collected. Calcium in samples was measured with ICP. Results: The apparent absorption rate of calcium in girls and boys were 46.4% and 68.7% respectively. There were significant differences between 4 groups on calcium in feces, calcium absorption and calcium retention. There was no plateau for boys and girls with curve estimation. The calcium absorption rate was the highest in boys when their calcium intakes were 665 mg/d . The calcium absorption rate plateau approached 45% in girls when their calcium intakes were 650 mg/d. To meet the need of deposition of mineral, calcium intake of boys should be 545 mg/d, and girls 1055 mg/d. Conclusion: There was significant differentce of calcium metabolism trend between boys and girls aged 12-17 y. The adequate calcium intake was 600-700 mg/d for Chinese boys,and 1000-1100 mg/d for girls.