Potassium Citrate (kcit) has long been utilized by physicians to combat stone formation in patients with hypocitraturia or aciduria. The most common obstacle to patient compliance with this medication has historically been dosing frequency, pill size, dyspepsia, and its familiar unpleasant taste. However, rampant increases in drug pricing by pharmaceutical companies, that have achieved market control of the drug supply, are triggering non-compliance in the subset of stone patients who depend on potassium citrate therapy to prevent stone recurrence.

Previous research has shown that certain commercially available beverages contain alkali citrate, of which orange juice (OJ) has the highest reported concentrations of potassium citrate based on ion chromatography. Unfortunately, the high sugar content of orange juice excludes its potential use as a dietary alternative to prescription potassium citrate. Recently, major beverage companies (Pepsi, Coca Cola) have release low calorie beverages with equivalent citrate content but with 50% less sugar. In early 2018 the investigaotrs performed ion-chromatography on various consumer beverages and validated that low calorie orange juice provided equivalent alkali citrate and malate to standard orange juice. The ion-chromatography also showed that the total amount of alkali/liter was greater in low calorie orange juice compared to crystal light lemon flavored. Currently, crystal light lemon is recommended as the next best option to water for recurrent stone formers with low urine volume production and hypocitraturia or aciduria (https://kidneystones.uchicago.edu/price-of-potassium-citrate/). However, there is a concern that the citrate within lemon based beverages is predominantly in an acidic form and thus has less potential to provide clinically affective levels of alkali despite a favorable alkali profile on ion chromatography.

Since low calorie orange juice was identified as a potential sources for citrate and alkali, the investigators wanted to show that consumption of the beverages resulted in desirable changes in urinary pH and citrate levels without negatively affecting patient well-being. Ten (10) volunteers drank standardized quantities of water, crystal light lemon juice, and two low calorie orange juices. After 7 days of beverage consumption the participants performed a 24 hour urine collection which was performed by an independent laboratory. The participants also maintained a diary of dietary (both food and drink) intake in addition to the trial beverages. The data from the study is very promising with desired changes in urinary pH and citrate levels with consumption of the low calorie orange juice. Minimal side effects were noted from consuming the low calorie orange juice except with Tropicana50 based on journals. It was determined that the artificial sweetener in TRP50 was the causative agent for GI symptoms and headaches. The preferred brand based on volunteer diaries was a generic brand by Kroger® low calorie orange beverage.

Our data suggests that low calorie orange juice has the potential to improve compliance rates with alkali therapy amongst recurrent stone formers. Stone prevention is key to reducing long-term sequelae of repeat surgical intervention such as iatrogenic genitourinary strictures, infections, and end organ damage. Additionally, there is a large cost savings potential with stone prevention by reducing hospital stays, surgical procedures, and missed work days due to stone disease. While daily low calorie orange juice may not completely supplant prescription potassium citrate therapy, it may be a favorable adjunct to reduce cost associated with potassium citrate and increase compliance rates by reducing the dose required to clinically relevant alkalization of the urine. Our hypothesis, is that patients with nephrolithiasis and evidence of hypocitraturia or aciduria who would otherwise be started on potassium citrate, can achieve similar urine alkalization with 500-1000 mL of daily low calorie orange juice consumption.