Effect of carbohydrate-electrolyte sports beverages on urinary stone risk factors.

Purpose: We evaluated the effects of consuming carbohydrate-electrolyte sports beverages (Gatorade (R)) on urinary stone risk factors. Materials and Methods: Twelve normal subjects (5 men, 7 women) and 12 hyper-calciuric stone formers (2 men, 10 women) participated in a 4-week prospective, crossover study consisting of 3 study phases. In phase 1 subjects were placed on a monitored stone prevention diet that was continued throughout the study. In phase 2 subjects ingested 2 l Gatorade daily followed by a 7-day washout period. In phase 3 subjects ingested 2 l water daily. On the final day of phases 1, 2 and 3 a 24-hour urine collection and blood sample were analyzed for stone risk factors. Effects of group and phase were tested using repeated measures ANOVA and paired t tests. Results: Changes in urinary risk factors after Gatorade consumption revealed no statistically significant difference between normal subjects and stone formers. However, intrasubject variation occurred in both groups. Gatorade consumption in both groups increased urinary pH (p = 0.006), urinary chloride (p = 0.044) and urinary sodium (p = 0.008), and decreased urinary potassium (p = 0.035) and urinary uric acid (p = 0.019) in a statistically significant manner. In response to Gatorade consumption urinary volume, calcium and citrate were unchanged compared to water consumption and baseline. Conclusions: Gatorade increased mean urinary sodium and chloride levels compared to water and baseline. However, the results were within normal urinary parameters. The change did not appear to be clinically significant as urinary calcium was unchanged. Overall consumption of Gatorade does not increase or decrease urinary stone risk factors.