A nurse is reinforcing teaching with a client who has received treatment for kidney stones. The nurse should remind the client to increase intake of which of the following?

A. Tea is incorrect because certain teas, especially black tea, contain oxalates, which can contribute to the formation of calcium oxalate kidney stones. Increasing tea intake could actually increase the risk of recurrence. B. Protein is incorrect because excessive intake of animal protein can increase calcium and uric acid excretion, raising the risk for kidney stone formation. Clients are generally advised to consume moderate amounts of protein rather than increase it. C. Sodium is incorrect because high sodium intake increases calcium excretion in the urine, which can promote the formation of calcium-based kidney stones. Clients are usually advised to limit sodium consumption. D. Water is correct because increasing fluid intake helps dilute the urine, decreasing the concentration of stone-forming substances such as calcium, oxalate, and uric acid. Adequate hydration is one of the most important strategies for preventing recurrence of kidney stones. Clients are typically advised to aim for at least 2–3 liters of fluid per day unless contraindicated by other health conditions.