Change of 24-hour Urinary Citrate Level after Dietary Manipulation with Lemon Juice in Urolithiasis Patients

Park, Nam Jong; Kim, Tae Kyu

Abstract

PURPOSE: Citrate is a well recognized inhibitor of the formation of calcium oxalate and calcium phosphate stones. Hypocitraturia is a common etiology of recurrent calcium nephrolithiasis, with an incidence of 19 to 63%. Potassium citrate therapy can be a useful therapeutic approach for the management of calcium nephrolithiasis. But pharmacological treatment of hypocitraturic calcium nephrolithiasis requires taking too many tablets, or numerous crystal package or liquid supplements throughout the day. This cumbersome regimen often decreases patient compliance. We administered dietary citrate via lemon juice to stone former and evaluated the change of citrate levels.
MATERIALS AND METHODS
The prospective study included 7 women and 8 men with documented recurrent or multiple urinary stone disease. None of the subjects suffered from renal impairment, urinary tract infection and other metabolic disorder. Controls comprised 6 voluntary men. They had no previous stone history and no evidence of stone. Patients ingested total 1 liter of lemon juice(containing 4.0gm/L.citrate) divided at 6 hours interval without strict diet restriction. Urine specimens were obtained for urinary citrate levels after 2-3days of lemon juice therapy and compared to pre-lemon juice baseline values.
RESULTS
All 15 patient showed increased urinary citrate levels during lemon juice therapy. Average urinary citrate levels increased from 146+/-109mg/day at baseline to 453+/-226mg/day during treatment(p<0.05). Urinary citrate levels during treatment increased up to those of control group(351+/-265mg/day) and did not show significant difference (p>0.05). Urinary pH increased from 5.9+/-0.4 at baseline to 6.8+/-0.6 during treatment(p<0.05). No patient complained of gastrointestinal discomforts.
CONCLUSIONS
Citrate supplementation with lemon juice increased urinary citrate levels and urinary pH. Lemon juice is well tolerated dietary source of citrate and would be beneficial in the control of calcium urolithiasis.