What is the optimal diet and food regimen to prevent nephrolithiasis (kidney stones)?

From the Guidelines

To prevent kidney stones, the optimal diet and food regimen should prioritize staying well-hydrated, limiting sodium and animal protein intake, and maintaining a moderate calcium intake from food sources. The American College of Physicians recommends management with increased fluid intake spread throughout the day to achieve at least 2 L of urine per day to prevent recurrent nephrolithiasis 1. Key dietary modifications include:

• Drinking 2-3 liters of water daily to dilute urine and reduce crystal formation
• Limiting sodium to less than 2,300 mg per day to reduce calcium in urine
• Reducing animal protein consumption to 6 ounces daily to minimize uric acid production and maintain urinary citrate levels
• Maintaining moderate calcium intake of 1,000-1,200 mg daily from food sources like dairy products, fortified plant milks, and leafy greens, while avoiding calcium supplements unless prescribed by a doctor
• Increasing citrus fruits like lemons, oranges, and grapefruits to inhibit stone formation through their citrate content
• Limiting oxalate-rich foods such as spinach, rhubarb, beets, chocolate, and nuts for those prone to calcium oxalate stones
• Reducing added sugar and sweetened beverages, particularly those with high fructose corn syrup These dietary changes aim to alter urine composition, creating less favorable conditions for crystal formation and aggregation, and addressing the underlying chemical imbalances that lead to kidney stones 1. For specific stone types, additional dietary modifications or pharmacologic therapies like potassium citrate supplements or allopurinol may be necessary, as recommended by the American College of Physicians 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 optimal diet and food regimen to prevent nephrolithiasis (kidney stones) includes:

• Sodium restriction: 100 mEq/day
• Oxalate reduction: limited intake of nuts, dark roughage, chocolate, and tea
• Moderate calcium restriction: 400-800 mg/day for patients with hypercalciuria 2

From the Research

Dietary Recommendations for Preventing Nephrolithiasis

• Adequate fluid intake is essential for preventing kidney stones, with a reduction in risk of 13% for every 200 mL of water consumed 3
• A balanced consumption of dairy products can reduce oxalate intestinal absorption and urinary excretion, being protective for stone disease 3
• Moderate calcium intake, typically not exceeding 1.2 g/day, is recommended 3
• Low dietary sodium is advised, as high sodium intake is associated with hypertension, heart disease, and stone risk 4, 3
• Limited animal protein intake is recommended, as it is associated with increased risk for stone formation, whereas vegetable and dairy proteins are not 4, 3
• A diet rich in fruits and vegetables is strongly recommended for stone formers, as it increases anti-lithogenic solutes and has an alkalizing effect 3

Specific Dietary Components

• Oxalate restriction is only advisable in patients with known elevated consumption, as the amount of oxalate contained in different foods is difficult to estimate and its intestinal absorption is influenced by external factors such as calcium intake 3
• High intake of animal proteins, particularly meat, is associated with increased purine metabolism and acid load, favoring uric acid nephrolithiasis 3
• Soft drinks are associated with a greater risk of stone events, whereas caffeine and citrus fruits juice are not 3

Comparison of Diets

• Vegetarian and Mediterranean diets are considered protective and useful for stone formers, due to their high content of fruits and vegetables, low animal protein, and balanced dairy product consumption 3
• Western diet is considered at risk for stone formation due to its high animal protein and sodium content 3
• Plant-based milk alternatives such as oat, macadamia, rice, and soy milk have similar parameters to dairy milk and may be suitable for patients with kidney stones, whereas almond and cashew milk have more potential stone risk factors 5