In all cases, more fluid is needed after exertion and during times of stress. If fluid intake is sufficient, the urine should be pale and almost watery, not dark and yellow. Although water is best, even water may vary in its effects. On the other hand mineral water containing both calcium and magnesium may reduce several risk factors for both calcium and uric acid stone formation. Cola beverages can severely reduce citrate in the urine and should be avoided.
Many soft drinks contain phosphoric acid, which increase the risk for stones.
A number of studies have found a risk for stones from drinking grapefruit juice. Fruit juices, particularly apple and cranberry juice, contain oxalates, although it is unclear whether oxalate-containing foods pose a risk for calcium oxalate stones. It should be noted, in fact, that cranberry juice helps prevent urinary tract infections and so may be helpful for reducing the risk for struvite stones. A 1999 study conducted in Finland suggests that the risk of developing stones decreases with beer consumption. This study found no effects from coffee, tea, or wine, but other research has reported a lower risk with these beverages.