Dr. Mohit Sharma MCh Urology AIIMS
Kidney stones affect over 1 in 10 people in their lifetime — and up to 75% will get another one within 20 years. The most common type is a calcium oxalate stone, which has led many patients to cut dairy and calcium. But science shows this is exactly backwards.
Why cutting calcium backfires: When you eat calcium with meals, it binds to oxalate in your gut — before both can reach your kidneys. Less dietary calcium means more oxalate gets absorbed, and more oxalate in your urine means more stones. A landmark clinical trial showed a low-calcium diet actually increased stone risk compared to a low-sodium, low-animal-protein diet.
What really drives stone formation:
• Too little water — the single biggest risk factor. Aim for at least 2 litres of urine output per day.
• Too much salt — raises calcium excretion in urine.
• Too much animal protein — increases urinary acid, calcium, and uric acid, all of which promote stones.
• High-oxalate foods in excess — spinach, rhubarb, Swiss chard, beet greens, cashews, and starfruit should be limited if you have a history of stones.
Bottom line :-
Eat adequate dairy or calcium-rich foods with meals. Drink water generously. Cut animal protein and salt. This combination — not calcium avoidance — is your best protection against recurrent kidney stones.