[摘要] ：

目的：通过人体实验研究中国人的“钙平衡”，估算国人的适宜钙摄入量，探讨钙剂治疗骨质疏松的根据。

方法：在不同“钙摄入量”下（碳酸钙干预为主），对11 名志愿者（7男、4女含两名孕妇，年龄12～80岁）进行了853 天“平衡”实验。 用 EDTA 滴定法检测食物钙、粪钙、尿钙含量。用SPSS 统计、分析数据。

结果：12岁少年摄入钙600 mg达到正平衡，每天获得钙85 mg；80岁老妪摄入钙650 mg，每天丢失钙216 mg；44岁女性摄入钙2900 mg，每天获得钙37 mg。摄入钙增至4900 mg，每天获得钙734 mg ；62岁男性摄入钙993 mg，每天丢失钙197 mg。摄入钙增至5680 mg，每天仅丢失钙28 mg；在低钙摄入下（每天≤ 700 mg ），80岁女性和62岁男性的钙吸收率仅为12岁少年的1/7和1/4。三代人的钙代谢特点是：少年高吸收、低尿钙、正平衡；青年高吸收、高尿钙、负平衡；老年低吸收、高尿钙、负平衡。

结论：国人的“钙摄入量”决定了“钙吸收和钙平衡”。尽管随年龄增长人体 “钙吸收能力”明显降低，但是只要将钙摄入量提高至每天3000～5000 mg，成年受试人便可以达到或接近正钙平衡。这是用“钙剂”治疗骨质疏松的理论根据。本研究证明，提高“钙摄入量”可以矫正钙平衡，治疗骨质疏松。

关键词 ：人体钙平衡实验；  钙摄入量；  钙吸收

A study on calcium intake in Chinese

       Zhaozeng Mi   Yongjian Luo

[Abstract]  Objective: To determine the optimal daily intake of calcium for Chinese people through a calcium balance study in Chinese subjects. This study will explore the use of calcium supplements to overcome the problem of osteoporosis. Methods: A trial was carried out on eleven volunteers (7 males, 4 females including 2 pregnant women) with an age range of 12 to 80 years old, over 853 days. Various doses of calcium supplement (the majority in a form of calcium carbonate) was administered to the volunteers. The content of calcium in their daily diet, faeces and urine were determined by EDTA titration. Analysis of the data was carried out using SPSS.  Results: A daily intake of 600mg of calcium resulted in a positive balance in the 12 years old subjects with the body retaining an average of 85mg of calcium. Intake of 650mg resulted in a negative balance in the 80 year old female with a loss of 216mg of calcium. Intake of 2900mg resulted in a 37mg calcium balance gain and increasing intake to 4900mg resulted in 734mg of positive balance in the 44 years old women. In the 62 years old male the intake of 993mg of calcium led to a loss of 197mg. By increasing the calcium intake to 5680mg the loss was reduced to only 28mg. At low level of calcium intake (DI £ 700mg), the absorption efficiency of the 80 year old female and 62 year old male are only 1/7 and ¼ compared to the 12 year old respectively. The characteristics of the calcium metabolism are as follows: high absorption of calcium with low calcium in the urine in the teenage, resulting in a positive balance; high absorption of calcium but accompanying with high calcium in urine, negative balance in youth; low absorption and high calcium in the urine leading to a negative balance in the advanced aged. Conclusions: the capability of calcium absorption of human body declines in the aged resulting in a negative calcium balance. However, the calcium balance can be restored to neutral or a positive level by increasing the calcium daily intake to the range 3000mg to 5000mg. Our study provides evidence that high dose calcium supplements may reduce the decline in calcium balance levels and be useful against osteoporosis and slow down the aging process.

Key Words: human calcium balance study, calcium dose, calcium adsorption

1.    前言

氧、碳、氢、氮、钙，是构成人体的五大“宏量元素”，其中“钙元素”名列第五。人体含“钙”超过1 kg，足见“钙”对人体之重要。近50年来，医学取得了长足的进步，唯独人体“钙代谢”研究进展迟缓 [1]。当前的“钙理论”存在诸多原则错误，原因是人体钙代谢实验不能大量、准确地测定“粪钙”。不掌握“粪钙数据”就无法确定“钙代谢”的平衡点，更无法确定人的“最佳钙摄入量”。美国的钙参考摄入量（DRIs = 800～1500 mg ）订低了，它不能维持本实验成年受试人的“钙平衡”[2]。

本实验对11名中国志愿者进行了853次“钙平衡”测定，结果表明“钙摄入量”是钙吸收和钙平衡的决定因素，提高钙摄入量是增加钙吸收和钙平衡的关键。成年人，每天摄入钙3000～5000 mg（不是800～1500 mg），才能接近或达到钙平衡。鉴于老年人的“钙吸收”能力随年龄而降低，60岁以上的人欲达到不丢钙，摄入量应当超过5000 mg/d，这是抵制骨钙丢失，预防、治疗骨质疏松的有效方案。本研究还发现：维生素D提升血钙是以“降低食物钙吸收，增加骨钙溶出”为代价的，所以VD与甲状旁腺素（PTH）同是骨质疏松的“加速剂”（另文发表）。只要各有关实验室能认真地开展人体实验，积累钙代谢的基础数据，一个正确的“钙理论”便会脱颖而出。

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