Lemon juice is more than just a key ingredient in drinks and sauces. When used in combination with other diet and medication changes it can help prevent kidney stones. In the January 1983 issue of the journal "Urology," M.J. Nicar reports that more than half of patients with kidney stones have a low amount of a substance called citrate in their urine, and this puts them at risk for forming kidney stones. Lemon juice is a good source of citrate and can be used to increase the citrate concentration in the urine in order to prevent kidney stones.
Background
Kidney stones are a common medical problem, and unfortunately once a kidney stone develops there is increased risk that another one will develop. Therefore, after the initial episode resolves the focus turns to preventing further stone development. Kidney stones develop because certain substances in the urine reach a high enough concentration that they form a solid.
Risk Factors
Certain characteristics of urine make it more likely or less likely to produce stones. A 24-hour urine test is necessary to analyze these characteristics in order to determine what risk factors are present. A urine that is concentrated, contains too much calcium, oxalate, cysteine or uric acid, is infected with bacteria or either too acidic or too basic favors stone formation. Also, having a low concentration of citrate in the urine, less than 320 mg/day, increases the likelihood of stone formation. It is helpful to know the composition of the stone.
Role of Citrate
Citrate works in multiple ways to prevent stone formation. First, it binds to calcium in the urine, and this prevents the calcium from being able to bind to other calcium in the urine, forming a stone. Second, if a stone has formed, citrate actually prevents more stones from forming. In the December 1993 issue of the "Journal of Urology," P. Barcelo, et al., report that citrate supplementation raised the urinary citrate concentration in those studied and is associated with a lower risk of recurrent stones in those with low urinary citrate before the start of treatment.
Using Lemon Juice
Citrate is available in several different prescription forms, but it is also found in certain foods, in particular lemons. The prescription forms of citrate are more effective than lemon juice at increasing the citrate concentration in the urine. However, these medications are not always tolerated, and lemon juice is an appropriate alternative. In the September 1996 issue of the "Journal of Urology," M.A. Seltzer, et al., report that consuming 120 ml of lemon concentrate mixed in 2 l of water per day worked well. The dilution not only helps with palatability but also increases the urine volume. Remember that concentrated urine favors kidney stone formation.
Conclusion
Lemon juice may be recommended by physicians to prevent stone recurrence. It is important to remember that this is used in combination with other diet changes and medications, based upon the kind of kidney stone and the risk profile determined by a 24-hour urine test.
References
- "Comprehensive Clinical Nephrology"; John Feehally, Jurgen Floege and Richard J. Johnson; 2007
- "Urology"; Low urinary citrate excretion in nephrolithiasis; MJ Nicar; January 1983
- "Journal of Urology"; A Prospective Study of Recurrence Rate and Risk Factors for Recurrence after a First Renal Stone; A Trinchieri, F Ostini, R Nespoli, F Rovera, E Montanari, G Zanetti; July 1999
- "Reviews in Urology"; Hypocitraturia: Pathophysiology and Medical Management; JM Zuckerman, DG Assimos; Summer 2009
- "Journal of Urology"; Dietary manipulation and lemonade to treat hypocitraturic calcium nephrolithiasis; MA Seltzer, RK Low, M McDonald, GS Shami and ML Stoller; September 1996
- "Journal of Urology"; Randomized double-blind study of potassium citrate in idiopathic hypocitraturic calcium nephrolithiasis; P Barcello, O Wuhl, E Servitge, A Rousaud, CY Pak; December 1993
