Dietary protein, calcium metabolism, and skeletal homeostasis revisited
Dietary protein, calcium metabolism, and skeletal homeostasis revisited
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DOI：
10.1093/ajcn/78.3.584s
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发表时间：
2003-09-01
影响因子：
7.1
通讯作者：
Insogna, KL
中科院分区：
文献类型：
--
作者：
Kerstetter, JE;O'Brien, KO;Insogna, KL
高蛋白质摄入量会增加尿钙排泄，如果持续摄入，会导致持续的高钙尿症。迄今为止，大多数人体钙平衡研究尚未发现膳食蛋白质对肠道钙吸收或血清甲状旁腺激素的影响。因此，通常得出结论，过量尿钙的来源是骨吸收增加。我们实验室最近的研究表明，膳食蛋白质的改变实际上会深刻影响肠道钙的吸收。在健康成年人的短期饮食试验中，我们将钙摄入量固定在20 mmol/d，而膳食蛋白质从0.7 g/kg增加到2.1 g/kg。20名妇女增加饮食蛋白质导致高钙尿[从低蛋白饮食期间的3.4 +/- 0.3（（x）/bar +/- SE）到高蛋白饮食期间的5.4 +/- 0.4 mmol/d]。膳食蛋白质的增加伴随着肠道钙吸收的显著增加，从18.4 +/- 1.3%增加到26.3 +/- 1.5%（通过双稳定同位素方法测定）。膳食蛋白质摄入量在0.8 g/kg及以下可能与肠道钙吸收减少相关，足以引起继发性甲状旁腺功能亢进。这些低蛋白饮食引起的矿物质代谢变化的长期后果尚不清楚，但饮食可能对骨骼健康有害。值得关注的是最近的几项流行病学研究，这些研究表明，习惯性食用低蛋白饮食的个体骨密度降低，骨丢失率增加。需要研究来确定低蛋白质摄入是否直接影响骨吸收率，骨形成，或两者兼而有之。
High dietary protein intakes are known to increase urinary calcium excretion and, if maintained, will result in sustained hypercalciuria. To date, the majority of calcium balance studies in humans have not detected an effect of dietary protein on intestinal calcium absorption or serum parathyroid hormone. Therefore, it is commonly concluded that the source of the excess urinary calcium is increased bone resorption. Recent studies from our laboratory indicate that alterations in dietary protein can, in fact, profoundly affect intestinal calcium absorption. In short-term dietary trials in healthy adults, we fixed calcium intake at 20 mmol/d while dietary protein was increased from 0.7 to 2.1 g/kg. Increasing dietary protein induced hypercalciuria in 20 women [from 3.4 +/- 0.3 ((x) over bar +/- SE) during the low-protein to 5.4 +/- 0.4 mmol/d during the high-protein diet]. The increased dietary protein was accompanied by a significant increase in intestinal calcium absorption from 18.4 +/- 1.3% to 26.3 +/- 1.5% (as determined by dual stable isotopic methodology). Dietary protein intakes at and below 0.8 g/kg were associated with a probable reduction in intestinal calcium absorption sufficient to cause secondary hyperparathyroidism. The long-term consequences of these low-protein diet-induced changes in mineral metabolism are not known, but the diet could be detrimental to skeletal health. Of concern are several recent epidemiologic studies that demonstrate reduced bone density and increased rates of bone loss in individuals habitually consuming low-protein diets. Studies are needed to determine whether low protein intakes directly affect rates of bone resorption, bone formation, or both.