Kidney stones are solid masses formed from the crystallization of minerals and salts in urine, such as calcium, oxalate, uric acid, phosphate, or cystine. Doctor Vu Thi Thanh of Bach Mai Hospital explains that calcium-containing stones account for about 80% of cases, primarily calcium oxalate and calcium phosphate stones. The remaining 20% include uric acid stones, infection (struvite) stones, and cystine stones, which result from genetic metabolic disorders.

Stones form when urine becomes concentrated, leading to higher concentrations of minerals. Small crystals gradually bind together to create a stone nucleus, which then grows over time. This process is more likely to occur when the body lacks substances that inhibit crystallization, such as citrate or magnesium.

Kidney stones are among the most common urinary tract diseases today. The good news is that this condition is entirely preventable through simple changes in daily diet and lifestyle.

**Drink enough water daily:** Insufficient water intake is a common cause of kidney stones. When the body is not adequately hydrated, urine volume decreases and becomes concentrated. This increases the concentration of minerals in the urine, creating favorable conditions for crystallization and stone formation. Therefore, drinking enough water is the simplest yet most effective measure. Adults should drink 2,5-3 liters of water daily to maintain a minimum urine output of about 2 liters per day. Filtered water should be prioritized; fresh orange or lemon juice is also beneficial due to its citrate content, which helps inhibit the crystallization process that forms stones.

**Limit salt:** High sodium intake causes more calcium to be excreted through urine. When combined with oxalate or phosphate, calcium readily forms stones. Total daily sodium intake should be below 2.000mg, equivalent to about one teaspoon of salt. It is necessary to limit sauces, processed foods, canned goods, pickled vegetables, fermented shrimp paste, and instant noodles.

**Maintain adequate calcium intake:** Adults should consume about 800-1.200mg of calcium daily from natural foods such as milk, yogurt, cheese, or small fish eaten with bones. Dietary calcium combines with oxalate directly in the intestines, reducing oxalate absorption into the body and protecting the kidneys.

**Control animal protein intake:** High consumption of red meat, organ meats, and certain purine-rich seafood increases uric acid in urine and makes the urine environment more acidic. These conditions are conducive to uric acid stone formation and increase the risk of calcium oxalate stones. Red meat, organ meats, and purine-rich seafood should be limited. Partially replacing these with plant-based protein sources from beans and legumes can help balance the urine environment.

**Limit oxalate-rich foods:** Foods that require controlled consumption include spinach, asparagus, chocolate, strong tea, almonds, cashews, and peanuts. If consumed, they should be eaten with calcium-rich foods or blanched with the first water discarded to reduce oxalate content. Vegetables like cabbage, cauliflower, chayote, peas, and fruits like pears and plums are more suitable choices.

**Increase potassium and magnesium-rich foods:** Bananas, avocados, dragon fruit, and various green vegetables are good sources of potassium and magnesium. These minerals help reduce calcium excretion in urine and limit the crystallization process that forms stones.

**Do not self-administer high-dose vitamin C:** People should not self-administer high-dose vitamin C preparations for extended periods without a doctor's prescription. The reason is that prolonged use of high-dose vitamin C (over 1.0.00mg/day) can increase oxalate levels in urine. Meanwhile, excessive vitamin D supplementation can increase calcium absorption and indirectly raise the risk of stone formation.

Experts note that there is no single diet suitable for all kidney stone patients. Each type of stone has a different formation mechanism and requires specific dietary recommendations. Therefore, patients should bring 24-hour urine test results, stone composition analysis, and medical records when consulting a nutrition specialist to receive personalized dietary advice, helping to reduce recurrence risk and protect kidney function long-term.

Le Nga