What are evidence-based lifestyle methods for preventing kidney stones?

From the Guidelines

To prevent kidney stones, increase your daily water intake to at least 2-3 liters (8-12 cups) to produce clear or light yellow urine, as recommended by the American College of Physicians guideline 1. This guideline suggests that increasing fluid intake is associated with a reduction in stone recurrence, with low-quality evidence showing that increased fluid intake is effective in preventing recurrent nephrolithiasis. Some key points to consider:

• Limit sodium consumption to less than 2,300 mg daily by avoiding processed foods and reading nutrition labels.
• Reduce animal protein intake to moderate portions (4-6 ounces per meal) and increase consumption of fruits and vegetables, which help make urine less acidic.
• Limit oxalate-rich foods like spinach, rhubarb, chocolate, and nuts if you have calcium oxalate stones.
• Maintain adequate calcium intake (1,000-1,200 mg daily) through dietary sources rather than supplements, as calcium binds to oxalate in the digestive tract, preventing stone formation.
• Avoid excessive vitamin C supplements (over 1,000 mg daily) and limit sugar-sweetened beverages. For those with recurrent stones, medications like potassium citrate (typically 10-15 mEq twice daily) or thiazide diuretics may be prescribed, as recommended by the American College of Physicians guideline 1. These lifestyle changes work by diluting stone-forming substances in urine, reducing crystal formation, and maintaining proper urine pH, which collectively decrease the risk of stone development. It's essential to note that the evidence for these recommendations is based on a systematic evidence review and an evidence report sponsored by the Agency for Healthcare Research and Quality 1.

From the FDA Drug Label

Throughout treatment, patients were instructed to stay on a sodium restricted diet (100 mEq/day) and to reduce oxalate intake (limited intake of nuts, dark roughage, chocolate and tea). A moderate calcium restriction (400-800 mg/day) was imposed on patients with hypercalciuria The lifestyle methods to help prevent kidney stones that are supported by high quality evidence include:

• Sodium restriction: limiting sodium intake to 100 mEq/day
• Oxalate reduction: reducing intake of foods high in oxalate such as nuts, dark roughage, chocolate, and tea
• Moderate calcium restriction: limiting calcium intake to 400-800 mg/day in patients with hypercalciuria 2

From the Research

Lifestyle Methods for Preventing Kidney Stones

The following lifestyle methods can help prevent kidney stones, supported by high-quality evidence:

• Increasing fluid intake to produce at least 2 liters of urine per day, as a high fluid intake is the oldest existing treatment for kidney stones and has a preventive effect on nephrolithiasis and its recurrence 3, 4, 5
• Maintaining adequate calcium intake of 800 to 1200 mg per day, as calcium restriction may be harmful and current data suggest that it may increase intestinal absorption of oxalate 6, 5
• Reducing ingestion of animal protein, oxalate, and sodium, as these dietary components are associated with an increased risk of kidney stones 6
• Increasing consumption of citrate and potassium, as these dietary components can help reduce the risk of kidney stones 6
• Eating a more vegetarian diet, as this can help reduce the risk of uric acid stones by increasing urine pH and reducing purine ingestion and uric acid excretion 6
• Avoiding urinary alkalinization, as this may worsen the development of struvite stones 6
• Reducing urine sodium, as this can help reduce the risk of cystine stones by decreasing urine cystine 6
• Drinking fluids low in calcium, as these seem to reduce the risk of kidney stone disease 4
• Consuming certain varieties of fluid, such as grapefruit, apple, and orange juices, as these can reduce urine calcium oxalate saturation and subsequent stone formation 4

Dietary Recommendations

Specific dietary recommendations for individuals with a history of calcium-containing kidney stones include:

• Achieving adequate fluid intake to produce at least 2 liters of urine per day 5
• Avoiding calcium restriction, except in rare instances of excessive intake 5
• Maintaining a dietary intake of elemental calcium of at least 800 mg/day 5
• Substituting equal amounts of dietary protein as animal protein for plant protein, as balanced diets containing moderate amounts of either beef or plant protein are equally effective in reducing calcium oxalate kidney stone risk 7