Can dietary calcium affect stone formation?
About 70 percent of stones are calcium-based. We used to recommend that everyone who had calcium-based stones decrease their calcium intake. We no longer recommend lowering the calcium intake, however, because calcium is important for the operation of muscles and for bone strength, and because some calcium in the diet is even good for preventing kidney stone formation. Calcium and a chemical called oxalate, which is found in fruits and vegetables, bind very tightly together, and form some of the hardest kidney stones. And oxalate is a much stronger promoter of stone growth and formation than calcium. If you don’t eat enough calcium, the oxalate in your intestinal tract will not be bound up by calcium, so more of this oxalate will be available for absorption. As a result, if you decrease your calcium intake, you end up raising your risk of stones by increasing the amount of oxalate that is absorbed. Are some calcium supplements better for people with a history of kidney stones than othe
