Changes in urinary chemical composition in healthy volunteers after consuming roselle (Hibiscus sabdariffa Linn.) juice.

The objective of this study was to evaluate the changes of urine in normal subjects after consuming roselle juice in different concentrations and durations which may help the treatment and prevention of renal stone disease. Thirty-six healthy men participated in the study, in which urinalysis, urine electrolytes and indices for measurements of concentration of urine were determined before, during and after roselle juice consumption. The urine after consumption of roselle juice showed a decrease of creatinine, uric acid, citrate, tartrate, calcium, sodium, potassium and phosphate but not oxalate in urinary excretion. The CPR values of the majority of each individual increased and means PI values decreased in phase 1. Contrarily, the CPR values of the majority of volunteers decreased and means PI values increased in phase 2. In conclusion a low dose of roselle juice (16 g/day) caused more significant decrease in salt output in the urine than a high dose (24 g/day). The urinary changes were similar to the observations on villagers with and without stones in northeastern Thailand.