If you've ever suffered the painful effects of kidney stones, your doctor may have recommended that in addition to eating a healthy diet rich in whole grains, fruits and vegetables, you should avoid dairy products, especially milk, as well as foods rich in oxalate such as walnuts, spinach, rhubarb, parsley, and chocolate. That's because kidney stones are formed when uric acid and calcium crystallize in the kidneys, and eating too much calcium and oxalate encourages their formation. A new study from the New England Journal of Medicine found that avoiding calcium wasn't necessarily the most effective way to reduce the occurrence of kidney stones - staying away from salt and animal protein and eating a normal amount of calcium may protect a person from kidney stones more effectively.

The 5-year study evaluated 120 men with recurrent kidney stones. Half of the men ate a diet with a normal amount of calcium and reduced amounts of animal protein and salt, and half the men ate only a low-calcium, low-oxalate diet. After 5 years, only 12 of the 60 men who ate the low-animal protein, low-salt, normal-calcium diet had relapses of kidney stones. In contrast, 23 of the 60 men who ate only the low-calcium diet had kidney stone relapses. The men on the normal-calcium diet had less than half the risk of the men on the low-calcium diet.

The formation of kidney stones is related to diet and nutrition, so it's important to eat a diet that prevents stone formation or recurrence. Consume plenty of leafy greens, whole grains, fruits, and vegetables, and drink plenty of water. Talk to your doctor about the advisability of special diets such as a diet low in calcium or low in animal protein and salt. This study indicates that making dietary changes such as reducing salt and animal protein intake could prevent the recurrence of kidney stones.

Related information Nutrition Center - Calcium

Sources:  Borghi L, Schianchi T, Meschi T, Guerra A, Allegri F, Maggiore U, Novarini A. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. New England Journal of Medicine 2002 Jan 10;346(2):77-84.