The importance of water and other fluids in the prevention of stone recurrence

The natural history of nephrolithiasis is characterized by a high recurrence rate making pharmacological and non-pharmacological secondary prevention measures necessary. Among these, dietary manipulations are of primary importance. Water therapy is one of the oldest therapeutic tools available: the increase in urinary flow reduces the concentration of urinary factors that promote stone formation without altering the effect of the inhibitors; it renders the urinary microenvironment less suitable for the formation and aggregation of crystals-and hence kidney stones-and prevents recurrences. Notwithstanding the widespread application and efficacy of this therapy, only one randomized controlled trial actually exists in literature. Except during acute episodes of renal colic, all patients suffering from stone disease should be prescribed a sufficient intake of water and other fluids to produce a urine volume of at least 2 L/24 h. Oligomineral water with a low NaCl content is preferable, associated to a diet with a high fruit and vegetable content, a low salt and protein intake, and a controlled calcium, fat, and carbohydrate intake.