What dietary modification can reduce recurrence risk for calcium oxalate stones?

• A. Low-sodium diet
• B. Adequate hydration and limiting high-oxalate foods
• C. High-oxalate diet to desensitize
• D. Calcium restriction

Answer: (B)

The idea is that calcium oxalate stones form when urine becomes supersaturated with calcium and oxalate. Increasing fluid intake pours more water through the kidneys, diluting the urine and reducing the concentration of stone-forming minerals. This lowers the chance that calcium and oxalate will crystallize and stick together to form stones.

Limiting foods high in oxalate further reduces the amount of oxalate that reaches the urine, which also lowers supersaturation and the likelihood of stone formation. Good context: many common high-oxalate foods include spinach, rhubarb, beets, nuts, chocolate, tea, and some berries; moderating these helps, especially if fluid intake is kept high.

It’s also helpful to note that dietary calcium isn’t usually restricted; calcium in the gut can bind oxalate and reduce its absorption, which can actually help prevent stones. The focus here—hydration plus limiting high-oxalate foods—is the most effective dietary adjustment for reducing recurrence risk.