Oral Potassium Citrate May Help Prevent Kidney Stones in Children on the Ketogenic Diet

Laurie Barclay, MD

July 27, 2009 — Oral potassium citrate supplementation may help prevent kidney stones in children who receive the ketogenic diet, according to the results of a study reported online July 13 in Pediatrics.

"Kidney stones occur in 6% of children who receive the KD," write Melanie A. McNally, BS, from the School of Medicine, Johns Hopkins University in Baltimore, Maryland, and colleagues. "Potassium citrate (Polycitra K [Cypress Pharmaceuticals]) is a daily oral supplement that alkalinizes the urine and solubilizes urine calcium, theoretically reducing the risk for kidney stones."

The study sample consisted of 313 children who started the ketogenic diet from 2000 to 2008 at Johns Hopkins Hospital and who had at least 1 month of follow-up. Indications for use of daily potassium citrate, 2 mEq/kg/day, were only in the setting of identified hypercalciuria for children receiving the ketogenic diet from 2000 to 2005. Since 2006, daily potassium citrate was administered empirically to all children receiving the ketogenic diet.

Kidney stones developed in 4 (2.0%) of 198 children who received potassium citrate preventatively and in 11 (10.5%) of 105 children who did not receive potassium citrate (P = .003). Since 2006, 2 children refused supplementation with potassium citrate; of these 2, a kidney stone developed in 1 child. Incidence of kidney-stones was 0.9% (1/106) in those receiving successful empiric administration of potassium citrate at onset of the ketogenic diet vs 6.7% (13/195) in those given potassium citrate only because of hypercalciuria (P = .02).

Although children who received potassium citrate had less acidic urine (mean pH, 6.8 vs 6.2; P = .002), serum acidosis was not reduced in this group. Potassium citrate was well tolerated with no apparent adverse effects.

"Oral potassium citrate is an effective preventive supplement against kidney stones in children who receive the KD [ketogenic diet], achieving its goal of urine alkalinization," the study authors write. "Universal supplementation is warranted."

Limitations of this study include lack of randomization.

"We advise initial education about the importance of regular Polycitra K use at the time of KD onset and subsequent reinforcement at each follow-up clinic," the study authors conclude. "Additional studies may help to determine whether higher dosages of Polycitra K would be completely preventive or could perhaps be combined with other supplements such as multivitamins to aid compliance."

The Pediatric Clinical Research Unit, National Institutes of Health/National Center for Research Resources and the Carson Harris Foundation supported this study. The study authors have disclosed no relevant financial relationships.

译文：

口服柠檬酸钾可以帮助生酮饮食儿童防止肾结石

作者：Laurie Barclay医师 

根据一项于2009年7月13日在线发表于小儿科医学期刊的研究结果，口服柠檬酸钾可能协助预防接受生酮饮食的儿童发生肾结石 

柠檬酸钾（polycitra k，cypress药厂）是一种每天使用、可以碱化尿液且使尿中钙溶出的口服补充液，理论上可以降低肾结石风险。

最近马里兰巴尔的摩约翰霍普金斯（Johns hopkins）医学院的melanie a. mcnally博士研究指出，在接受生酮饮食的儿童中，约有6%发生肾结石。

这项研究样本包括313位符合每天使用柠檬酸钾适应症的儿童，于2000年至2008年间开始于约翰霍普金斯医院食用生酮饮食，每位儿童至少接受一月以上的后续追踪。

2000年至2005年间，接受生酮饮食发生高尿钙的儿童，这些儿童接受每天每公斤2 meq的剂量柠檬酸钾。从2006年后，所有接受生酮饮食的儿童都经验性地使用柠檬酸钾。198位使用柠檬酸钾预防的儿童中有4位（2.0%），105位没有使用柠檬酸钾的儿童有11位（10.5%）发生肾结石（p=0.003）。从2006年开始，2位儿童拒绝补充柠檬酸钾；这2位儿童中有1位患上肾结石。

在开始使用生酮饮食时，成功接受预防性柠檬酸钾的儿童，肾结石的发生率0.9%（1/106），因为高尿钙才接受柠檬酸钾的儿童则是6.7%（13/195）。

虽然接受柠檬酸钾的儿童尿液比较偏碱性（平均ph值为6.8相较于6.2；p=0.002），但这一组的血液酸碱值并未下降。柠檬酸钾的耐受性良好，且无显著副作用。

研究作者们写到，口服柠檬酸钾对接受生酮饮食的儿童而言，是个有效预防肾结石的补充品，可以达到碱化尿液的目标，值得全面补充。

但是这项研究的缺乏随机分组。

研究作者们的结论是，我们建议开始使用生酮饮食时，教育有关于常规补充柠檬酸钾的重要性，之后要在每次就诊时强调其重要性。这项研究将有助于确认高剂量柠檬酸钾是否可以完全地预防或是可以与其它补充品合并使用，例如复方维他命，来增加顺应性。

在国内生酮饮食患者中，许多家长也会在生酮饮食期间为患儿补充枸橼酸钾（柠檬酸钾）来预防肾结石。生酮饮食期间也要主要补充膳食纤维来预防小孩便秘的问题。而且钙磷的吸收也对孩子的身体发育有着重要的作用。所以家长在孩子进行生酮饮食期间，不仅要注意食物的比例问题，还需要对孩子的发育，预防副作用等方面考虑。生酮饮食虽然比较繁琐，但同时也是家长学习的一个机会。现在孩子生活条件比以前都要好，但许多家长缺乏对孩子营养方面的知识，导致孩子过肥、过瘦、营养不良等问题。孩子在饮食方面没有选择性，父母对孩子食物的选择影响到孩子营养吸收和发育。没有好的饮食习惯，只会导致孩子容易偏食，营养缺乏等问题。所以不仅生酮饮食患者的父母需要控制小孩的饮食营养，所有家长都需要懂得控制自己和小孩饮食，保持均衡的饮食习惯，才是人生幸福之道。

 了解更多：生酮饮食