The results point to a new dietary approach to manage kidney stones, according to Dr. Loris Borghi from the University of Parma in Italy and colleagues. Reducing calcium intake has not been shown to reduce the risk of recurrent stones over the long term and may cause calcium deficiency, which can weaken the bones. Restricted intake of animal protein and salt, combined with a normal calcium intake, provides greater protection than the traditional low-calcium diet.
A diet that restricts animal protein and salt is thought to reduce the urinary excretion of oxalate, a compound that combines with calcium and other compounds to form the deposits commonly known as kidney stones, the researchers explain. Low-calcium diets, on the other hand, may reduce urinary excretion of calcium but they also cause levels of oxalate in urine to rise.