This is untrue. Since most (80%) kidney stones are made up of calcium oxalate or calcium phosphate there has been a false notion that calcium rich foods are either responsible for stone formation or increase the risk of existing stones. But calcium from foods isn’t responsible.
In fact you need to consume the recommended dietary allowance (RDA) of 1300 mg of calcium daily to reduce your risk (almost 34%) of developing kidney stones. Three servings of dairy products (milk, cheese, etc.) daily with a healthy mix of leafy green vegetables and bony fish like sardines and pilchards, helps fulfill this RDA requirement. So don’t skip the milk if you wish to keep your kidneys clear of problematic stones.
Calcium supplements and calcium oxalate rich foods like chocolate, spinach, nuts and rhubarb are best consumed in moderation to prevent the risk of kidney stone formation. Your GP or Urologist will advise you to stay off these foods when you develop calcium kidney stones. In case you take calcium supplements ensure that you reduce the other calcium rich foods to stay within the RDA limits.