Matsumoto Edward D, Heller Howard J, Adams-Huet Beverley, Brinkley Linda J, Pak Charles Y C, Pearle Margaret S
Department of Urology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
J Urol. 2006 Jul;176(1):132-6. doi: 10.1016/S0022-5347(06)00565-9.
Recent studies suggest that a high calcium diet protects against calcium oxalate stone formation. We compared the effect of high and low calcium diets on urinary saturation of calcium oxalate during liberal oxalate intake.
A total of 10 healthy subjects (5 male, 5 female) participated in a 2-phase, randomized, crossover study comparing high (1,000 mg daily) and low (400 mg daily) calcium intake on a liberal oxalate diet (200 mg daily). During each phase subjects adhered to an instructed diet for 3 days followed by a controlled, metabolic diet for 4 days. Blood and 24-hour urine specimens collected on the last 2 days of each phase were analyzed for serum biochemistry studies and stone risk factors, respectively.
Urinary calcium was higher (mean +/- SD 171 +/- 64 vs 124 +/- 49 mg daily, p = 0.002) and oxalate was lower (25 +/- 4.8 vs 27 +/- 4 mg daily, p = 0.02) on the high vs low calcium diet. Overall, the urinary relative saturation ratio of calcium oxalate was higher on the high compared with the low calcium diet (3.3 vs 2.5, p <0.0001) even after adjusting for confounding variables.
In normal subjects urinary saturation of calcium oxalate was higher on a high calcium diet than a low calcium diet during liberal oxalate intake because the decrease in urinary oxalate did not overcome the effect of increased calcium. A high calcium diet during liberal oxalate intake may pose an increased risk of calcium oxalate stone formation.
近期研究表明，高钙饮食可预防草酸钙结石形成。我们比较了高钙饮食和低钙饮食在自由摄入草酸盐期间对草酸钙尿饱和度的影响。
共有10名健康受试者（5名男性，5名女性）参与了一项两阶段、随机、交叉研究，比较高钙（每日1000毫克）和低钙（每日400毫克）摄入对自由草酸盐饮食（每日200毫克）的影响。在每个阶段，受试者遵循指示饮食3天，然后进行4天的控制代谢饮食。分别分析每个阶段最后2天采集的血液和24小时尿液样本，进行血清生化研究和结石风险因素分析。
高钙饮食组的尿钙较高（平均±标准差：每日171±64 vs 124±49毫克，p = 0.002），草酸盐较低（每日25±4.8 vs 27±4毫克，p = 0.02）。总体而言，即使在调整混杂变量后，高钙饮食组草酸钙的尿相对饱和度仍高于低钙饮食组（3.3 vs 2.5，p <0.0001）。
在正常受试者中，自由摄入草酸盐期间，高钙饮食组草酸钙的尿饱和度高于低钙饮食组，因为尿草酸盐的降低并未抵消钙增加的影响。自由摄入草酸盐期间的高钙饮食可能会增加草酸钙结石形成的风险。
