Urine flows continuously through the urinary tract like running water in a river. It is not purely clear liquid as it dissolves numerous metabolic wastes and inorganic salts. Urolithiasis develops when solutes including calcium, oxalic acid and uric acid become overly concentrated or urine volume drops, causing discomfort and pain. Adjusting daily eating habits provides a simple and effective way of prevention.

Drink plenty of fluids

A daily fluid intake of over 3 liters is recommended to produce more than 2.5 liters of urine daily. Ample water and frequent urination reduce supersaturation of stone-forming substances and prevent renal calculi. Plain boiled water, orange juice and lemonade are preferred; limit excessive coffee, black tea and cola drinks.

Consume adequate dairy products

Eat more dairy foods such as milk and cheese, as well as tofu and small fish to maintain moderate to slightly high dietary calcium levels. Adults need 1–1.2 grams of calcium per day. Insufficient dietary calcium boosts intestinal absorption of oxalic acid and raises oxalate excretion in urine. Calcium oxalate crystals act like tiny gravel that clump together to form stones.

Limit spinach intake

Patients with a history of calcium oxalate stones should avoid large servings of high-oxalate foods. Spinach contains the highest oxalic acid content; other high-oxalate items include kale, almonds, peanuts, beetroot and black tea.

Avoid excessive vitamin C supplements

Vitamin C metabolizes into oxalic acid. High vitamin C intake drastically increases urinary oxalate and elevates the risk of calcium oxalate stones. Those with prior calcium oxalate stones should limit daily vitamin C intake to less than 1 gram.

Reduce meat consumption

Cut down on excessive animal protein. High-protein diets raise urinary calcium and oxalate excretion, lower urinary citrate levels and acidify urine, all of which facilitate calcium-based urinary stones.

Animal offal (liver, kidneys), sardines and anchovies are high in purines, which break down into uric acid. Uric acid accelerates the precipitation of urinary oxalates and stone formation. Daily purine intake should be kept below 500 milligrams.

Supplementary tip

Increase vegetable and fruit intake to maintain a balanced diet. Healthy dietary habits serve as the best measure to ward off urolithiasis and its adverse impacts.