Orange Juice Fends Off Renal Calculi Bay Better than Lemonade

DALLAS, Sept. 1 -- For those with renal calculi who are intolerant of Urocit-K (potassium citrate), orange juice may outdo lemonade, according to small, crossover study.

Both have high a citrate content, but only orange juice reduced urinary markers of stone-formation risk consistently better than water alone, reported Clarita V. Odvina, M.D., of the University of Texas Southwestern Medical Center here, in the Oct. 26 issue of the Clinical Journal of the American Society of Nephrology.

Orange juice provided an alkali load, promoted elevated urinary citrate levels, and reduced the crystallization potential of calcium oxalate and uric acid whereas lemonade did not, she said.

As reported in May at the American Urological Association meeting, lemonade and other juices containing dietary citrate may be an option for patients who cannot tolerate Urocit-K) because of GI side effects or other reasons.

"Foods that are high in citrate content generally are assumed to deliver alkali load when consumed irrespective of the accompanying cation [bound to the citrate]," Dr. Odvina wrote.

However, her National Institutes of Health-sponsored study found that orange juice with its potassium cation provided a better alkaline load, which helps reduce the acidity of urine and aggregation of crystals that would form kidney stones, compared with lemonade with its proton cation.

She found that:

• Orange juice improved urine alkalinity with a 0.6 higher pH compared with both lemonade and water.
• Orange juice increased net gastrointestinal alkali absorption to 52.7 mEq/day versus 7.6 mEq/day with lemonade and 11.1 mEq/day with water (P

Dr. Odvina said the difference could be due to study design differences, particularly with respect to diet.

However, she acknowledged the study was limited by its short observation period and indirect measures of stone formation rather than looking at symptomatic stone incidence as done in long-term studies. The researcher cautioned that additional, particularly long-term studies will be needed to confirm these results.

Based on the findings, "orange juice but not lemonade potentially could play an important role in the management of recurrent nephrolithiasis and may be considered an option in patients who are intolerant of potassium citrate," Dr. Odvina wrote.