Eighty percent of kidney stones contain calcium oxalate, calcium phosphate, or both. Other stones consist of struvite, uric acid, or cystine. Surprisingly, a review of 36 studies shows that stone recurrence is not prevented by assessing the chemical type of stone or doing blood and urine chemistries other than calcium levels. Here are the current recommendations for preventing kidney stones:
• Drink enough water to make you urinate at least eight cups of urine per day. Strong evidence shows that this is the most effective step in preventing kidney stones. Do not waste your money on expensive low-mineral waters; they offer no advantage over ordinary tap water.
• Restrict foods high in oxalates, such as chocolate, beets, nuts, rhubarb, spinach, strawberries, tea, and wheat bran. Oxalates can bind to calcium to form calcium oxalate stones.
• People who have had more than one attack of painful kidney stones may want to consider taking thiazide diuretics, citrate or allopurinol. Taking all three drugs has not been shown to be more beneficial than taking just one. No data exist to show that one thiazide diuretic is better than any other. Thiazide diuretics can cause dizziness, belly cramps, fatigue, and muscle cramps. Citrates can cause belly cramps, and allopurinol can cause a low white blood cell count.
• Magnesium pills have not been shown to prevent kidney stones.
• We have no data to show that a high-fiber diet prevents kidney stones, although it may.
• Check blood and urine levels of calcium. Having high blood and urine calcium can cause kidney stones.