A diet rich in calcium reduces the risk of kidney stones.
"Because the majority of stones contain calcium and because hypercalciuria (too much calcium) has been associated with the formation of stones, calcium restriction has been routinely recommended for patients who have kidney stones. However, we are unaware of any data that demonstrate that restriction of calcium intake reduces the recurrence of kidney stones," say the researchers.
The calcium rich foods offering the best protection against kidney stones are skim or low fat milk, and cottage or ricotta cheese. Calcium supplements were not found to have the same effect. "Nondairy sources of calcium such as oranges and broccoli also appeared to be protective," says the researchers. They found that a high intake of animal protein was "directly associated" with the risk of kidney stones.