The Effect of Lemonade and Diet Lemonade Upon Urinary Parameters Affecting Calcium Urinary Stone Formation

Purpose: To determine the effects of regular and diet lemonade upon urinary parameters affecting kidney stone formation. Methods: In this prospective blinded crossover study, 12 healthy participants consumed either 2L of regular or diet lemonade daily while on a standardized low sodium moderate calcium diet. Twenty four-hour urine collections were obtained at baseline on the controlled diet only and on days 4 and 5 of each treatment phase. There was a 1-week washout period between regular and diet lemonade treatments. Primary outcomes were urine citrate, pH, and volume determined by 24-hour urine collections. Secondary outcomes included the supersaturation of calcium oxalate, calcium phosphate, and uric acid. Results: Urine volume was significantly higher with both regular and diet lemonade consumption compared with baseline values. Urinary citrate significantly increased from baseline with diet lemonade only. Urine pH was unchanged with both beverages. The supersaturation of calcium oxalate significantly decreased with diet lemonade only, whereas supersaturation of calcium phosphate decreased with both beverages. Daily consumption of 2L of regular and diet lemonade resulted in an intake of 168.4 and 170.2mEq of citrate but a total alkali intake of 12.2 and 16.0mEq, respectively. Compared with diet lemonade, regular lemonade provided subjects with 805 additional calories and 225g of sugar per day. Conclusions: Diet lemonade may provide a low-calorie sugar-free cost-effective option for decreasing the risk of recurrent calcium nephrolithiasis through a significant increase in urine volume, increase in urinary citrate, and reduction in supersaturation of calcium oxalate and calcium phosphate.