What to eat and avoid if you have kidney stones?

Vegetables are rich in fiber, vitamins, and minerals, but some, especially those containing oxalate, can combine with calcium to form urinary tract stones—most commonly calcium oxalate stones.

According to Dr. Nguyen Anh Duy Tung of Nutrihome Nutrition Center, eating oxalate-rich foods does not necessarily cause kidney stones. However, those who have had stones or are at high risk should monitor their oxalate intake to lower the chance of recurrence.

High-oxalate vegetables do not need to be completely avoided, but patients should eat a variety of produce, maintain a balanced diet, choose appropriate cooking methods to preserve nutrients, and drink 2–2.5 liters of water daily. Adequate hydration helps dilute minerals in urine, reducing stone formation.

A woman washing celery. Illustration photo by Pexels

Dr. Tung recommends pairing vegetables with foods naturally rich in calcium, such as milk, cheese, small fish eaten with bones, or tofu. Consumed together, calcium binds with oxalate in the digestive tract, reducing its absorption and allowing it to be excreted as an insoluble compound. Conversely, a low-calcium diet may increase oxalate absorption and the risk of stones. Patients should also limit salt, reduce excessive animal protein, and avoid high-dose vitamin C supplements, as excess vitamin C can convert to oxalate.

Those at risk should avoid holding in urine, drinking too little water, taking unverified supplements, or overusing diuretics, as these can raise mineral concentrations in urine and promote stone formation.

For prevention, Dr. Tung advises maintaining a healthy weight and exercising regularly. People with a history of kidney stones should follow their treatment plan, undergo regular nutrition check-ups, assess body composition using the InBody 770 machine, and check micronutrient levels via high-performance liquid chromatography (UPLC). These tests help identify nutrient deficiencies or excesses so doctors can recommend tailored dietary adjustments and appropriate vitamin and mineral supplementation.