From the Guidelines
The best diet for preventing kidney stones focuses on increased fluid intake, particularly water, to produce at least 2-2.5 liters of urine daily, as recommended by the American College of Physicians guideline 1.
Key Dietary Recommendations
- Limit sodium to less than 2,300 mg per day, as high sodium increases calcium in urine.
- Reduce animal protein consumption (meat, eggs, fish) to 0.8-1 gram per kilogram of body weight daily.
- For calcium stones, which are most common, maintain adequate calcium intake (1,000-1,200 mg daily) from food sources rather than supplements.
- Limit oxalate-rich foods like spinach, rhubarb, nuts, and chocolate if you form calcium oxalate stones.
- Increase citrate consumption through citrus fruits like lemons and oranges, as citrate inhibits stone formation.
- Moderate your intake of sugar-sweetened foods and drinks, especially those with high fructose corn syrup. These dietary changes work by altering urine composition to make it less favorable for crystal formation, as supported by studies 1.
Mechanism of Action
Dilute urine from increased fluid intake contains fewer stone-forming minerals, while reduced sodium and animal protein decrease calcium and uric acid excretion. Dietary calcium binds to oxalate in the gut, preventing its absorption and subsequent excretion in urine where it could form stones, as explained in the guideline 1.
Evidence Quality
The American College of Physicians guideline 1 provides moderate-quality evidence for these recommendations, based on a systematic evidence review and an evidence report sponsored by the Agency for Healthcare Research and Quality.
Clinical Implications
By following these dietary recommendations, individuals can reduce their risk of developing kidney stones, as supported by studies 1.
From the Research
Dietary Recommendations for Preventing Kidney Stones
The best diet for preventing kidney stones involves several key components:
- High fluid intake: aim for at least 6-8 glasses of liquid per day 2, 3, 4
- Balanced calcium intake: 1000-1200 mg per day from dairy products or calcium supplements 5, 4
- Moderate protein intake: restrict animal protein and increase plant-based protein sources 5, 6, 4
- Low sodium intake: restrict sodium to recommended values to reduce hypercalciuria 5, 4
- High intake of fruits and vegetables: alkalizing foods that increase anti-lithogenic solutes such as citrate, potassium, and magnesium 5, 4
Specific Dietary Patterns
Certain dietary patterns have been shown to be beneficial for preventing kidney stones:
- DASH-style diet: high in fruits and vegetables, moderate in low-fat dairy products, and low in animal proteins and salt 5
- Vegetarian diet: rich in fruits and vegetables, low in animal proteins, and high in plant-based protein sources 4
- Mediterranean diet: rich in fruits and vegetables, whole grains, and healthy fats, and low in animal proteins and salt 4
Foods to Limit or Avoid
Certain foods may increase the risk of kidney stone formation:
- Soft drinks: associated with a greater risk of stone events 4
- Animal proteins: increase the risk of stone formation, especially when consumed in excess 5, 6, 4
- High-oxalate foods: may be problematic for individuals with elevated oxalate consumption, but restriction is only advisable in these cases 4
- High-sodium foods: increase the risk of hypercalciuria and stone formation 5, 4