Lime juice as a dietary alternative to mist potassium citrate for urine alkalinisation: A prospective, cross-over clinical trial.

Introduction: Urinary citrate is a potent inhibitor of urinary crystallization that is freely filtered in the proximal tubule of the kidney. We aimed to investigate the effect of citrate supplementation with fresh lime juice on the urinary pH and calcium excretion level among healthy individuals compared with that of mist potassium citrate.

Method: In this prospective, cross-over single-centre study, 50 healthy medical student volunteers were randomly allocated to two treatment arms. One arm was prescribed with potassium citrate, while the other arm received citrate supplementation with a home preparation of fresh lime juice. The urinary pH and calcium-to-creatinine ratio (uCa/uCr) were measured at baseline and after 7 days of treatment. This was followed by a washout period of 2 weeks, after which each participant crossed over to the other treatment arm, and the urinary measurements were repeated.

Results: Potassium citrate significantly increased the urinary pH among all participants, while fresh lime juice did not. Both fresh lime juice and potassium citrate reduced the uCa/uCr, although this effect was not significant.

Conclusion: Fresh lime juice is not as effective as potassium citrate in improving the urinary pH and calcium excretion level of healthy individuals. Therefore, it should be used as an adjunct rather than an alternative to potassium citrate.