Water from stone: Self-prevention of kidney stones

This study investigated the effects of daily fluid intake on the formation of kidney stones.

Authors concluded that increasing daily water intake has the potential to prevent kidney stone formation.

Increased daily fluid intake has been shown to protect against the formation of urinary stones. However, the precise association between the amount of fluid and kidney stone risk are not entirely clear. The effect of specific types of fluids on such risk are unclear as well.

This review assessed the association between fluid intake and kidney stone risk. 15 studies, including a total of 351,081 participants and 9601 kidney stone cases, were analyzed.

Analysis found that each 500 mL increase in daily water intake was associated with a 7% reduced risk of kidney stone formation. Drinking more than 2000 mL of water per day was found to reduce the risk of first kidney stone formation by at least 8% compared to 1500 mL daily intake. Drinking more than 3100 mL per day was associated with a 26% reduction of kidney stone risk compared to 1500mL per day.

Less pronounced associations were also found for increased tea intake. Increased alcohol intake was also noted to reduce the risk of kidney stone formation (although this should not be understood as a recommendation to increase alcohol consumption). A trend towards reduced risk of kidney stone formation was also noted with increased coffee intake. The risk of kidney stones was not related to juice, soda or milk intake. 

This analysis concluded that increased water intake is associated with a reduced risk of kidney stones.

The studies included in this analysis were small, failed to account for various additional factors related to kidney stone risk and fluid intake, and were of overall low quality. Results therefore should be interpreted with care.