Hiatt R A, Ettinger B, Caan B, Quesenberry C P, Duncan D, Citron J T
Division of Research, Kaiser Permanente Medical Care Program, Oakland, CA 94611-5714, USA.
Am J Epidemiol. 1996 Jul 1;144(1):25-33. doi: 10.1093/oxfordjournals.aje.a008851.
Low protein diets are commonly prescribed for patients with idiopathic calcium nephrolithiasis, who account for > 80% of new diagnoses of kidney stones. This dietary advice is supported by metabolic studies and epidemiologic observational studies but has not been evaluated in a controlled trial. Using 1983-1985 data from three Northern California Kaiser Permanente Medical Centers, the authors randomly assigned 99 persons who had calcium oxalate stones for the first time to a low animal protein, high fiber diet that contained approximately 56-64 g daily of protein, 75 mg daily of purine (primarily from animal protein and legumes), one-fourth cup of wheat bran supplement, and fruits and vegetables. Intervention subjects were also instructed to drink six to eight glasses of liquid daily and to maintain adequate calcium intake from dairy products or calcium supplements. Control subjects were instructed only on fluid intake and adequate calcium intake. Both groups were followed regularly for up to 4.5 years with food frequency questionnaires, serum and urine chemistry analysis, and abdominal radiography; and they were urged to comply with dietary instructions. In the intervention group of 50 subjects, stones recurred in 12 (7.1 per 100 person-years) compared with two (1.2 per 100 person-years) in the control group; both groups received a mean of 3.4 person-years of follow-up (p = 0.006). After adjustment for possible confounding effects of age, sex, education, and baseline protein and fluid intake, the relative risk of a recurrent stone in the intervention group was 5.6 (95% confidence interval 1.2-26.1) compared with the control group. The authors conclude that advice to follow a low animal protein, high fiber, high fluid diet has no advantage over advice to increase fluid intake alone.
低蛋白饮食通常被开给特发性草酸钙肾结石患者，这类患者占新诊断肾结石病例的80%以上。这种饮食建议得到了代谢研究和流行病学观察性研究的支持，但尚未在对照试验中进行评估。作者利用来自北加利福尼亚州三个凯撒医疗中心1983 - 1985年的数据，将99名首次患有草酸钙结石的患者随机分为两组，一组采用低动物蛋白、高纤维饮食，每天摄入约56 - 64克蛋白质、75毫克嘌呤（主要来自动物蛋白和豆类）、四分之一杯麦麸补充剂以及水果和蔬菜。干预组的受试者还被要求每天饮用六至八杯水，并通过乳制品或钙补充剂保持充足的钙摄入量。对照组受试者仅被告知要保证液体摄入量和充足的钙摄入量。两组均通过食物频率问卷、血清和尿液化学分析以及腹部X光检查进行长达4.5年的定期随访；并督促他们遵守饮食指导。在50名受试者的干预组中，有12人复发结石（每100人年7.1例），而对照组为2人（每100人年1.2例）；两组平均随访3.4人年（p = 0.006）。在对年龄、性别、教育程度以及基线蛋白质和液体摄入量可能的混杂效应进行调整后，干预组复发结石的相对风险为5.6（95%置信区间1.2 - 26.1），而对照组为1。作者得出结论，遵循低动物蛋白、高纤维、高液体饮食的建议并不比仅增加液体摄入量的建议更具优势。
