Department of Clinical Sciences, University of Parma, Parma, Italy.
Am J Clin Nutr. 2010 Mar;91(3):565-70. doi: 10.3945/ajcn.2009.28614. Epub 2009 Dec 30.
A direct relation exists between sodium and calcium excretion, but randomized studies evaluating the sustained effect of a low-salt diet on idiopathic hypercalciuria, one of the main risk factors for calcium-oxalate stone formation, are still lacking.
Our goal was to evaluate the effect of a low-salt diet on urinary calcium excretion in patients affected by idiopathic calcium nephrolithiasis.
Patients affected by idiopathic calcium stone disease and hypercalciuria (>300 mg Ca/d in men and >250 mg Ca/d in women) were randomly assigned to receive either water therapy alone (control diet) or water therapy and a low-salt diet (low-sodium diet) for 3 mo. Twenty-four-hour urine samples were obtained twice from all patients: one sample at baseline on a free diet and one sample after 3 mo of treatment.
A total of 210 patients were randomly assigned to receive a control diet (n = 102) or a low-sodium diet (n = 108); 13 patients (2 on the control diet, 11 on the low-sodium diet) withdrew from the trial. At the follow-up visit, patients on the low-sodium diet had lower urinary sodium (mean +/- SD: 68 +/- 43 mmol/d at 3 mo compared with 228 +/- 57 mmol/d at baseline; P < 0.001). Concomitant with this change, they showed lower urinary calcium (271 +/- 86 mg/d at 3 mo compared with 361 +/- 129 mg/d on the control diet, P < 0.001) and lower oxalate excretion (28 +/- 8 mg/d at 3 mo compared with 32 +/- 10 mg/d on the control diet, P = 0.001). Urinary calcium was within the normal range in 61.9% of the patients on the low-salt diet and in 34.0% of those on the control diet (difference: +27.9%; 95% CI: +14.4%, +41.3%; P < 0.001).
A low-salt diet can reduce calcium excretion in hypercalciuric stone formers. This trial was registered at clinicaltrials.gov as NCT01005082.
钠和钙的排泄之间存在直接关系，但评估低钠饮食对特发性高钙尿症（草酸钙结石形成的主要危险因素之一）的持续影响的随机研究仍然缺乏。
我们的目标是评估低钠饮食对特发性钙肾结石患者尿钙排泄的影响。
患有特发性钙结石病和高钙尿症（男性>300mg Ca/d，女性>250mg Ca/d）的患者被随机分配接受单独水疗（对照饮食）或水疗和低钠饮食（低钠饮食）治疗 3 个月。所有患者均采集 24 小时尿液样本两次：一次在自由饮食时基线，一次在治疗 3 个月后。
共有 210 名患者被随机分配接受对照饮食（n=102）或低钠饮食（n=108）；13 名患者（对照组 2 名，低钠饮食组 11 名）退出试验。在随访时，低钠饮食组的尿钠较低（3 个月时平均+/-SD：68+/-43mmol/d，与基线时的 228+/-57mmol/d相比；P<0.001）。伴随着这种变化，他们的尿钙也较低（3 个月时 271+/-86mg/d，与对照组的 361+/-129mg/d相比，P<0.001），草酸盐排泄也较低（3 个月时 28+/-8mg/d，与对照组的 32+/-10mg/d相比，P=0.001）。低钠饮食组 61.9%的患者尿钙处于正常范围内，而对照组为 34.0%（差异：+27.9%；95%CI：+14.4%，+41.3%；P<0.001）。
低钠饮食可减少高钙尿结石患者的钙排泄。本试验在 clinicaltrials.gov 上注册为 NCT01005082。
