No, proteins do not promote decalcification of the bones. A bone is a tissue containing proteins on which calcium phospate crystals are bound. To maintain healthy bones, they need a supply of proteins, phosporus and calcium. These three nutrients are present in milk and milk products. The amount of calcium in bones depends on the amount of calcium absorbed in the intestine and the amount excreted in the urine. An increased intake of proteins (whether they are from animal or plant origin) may sometimes lead to a loss of calcium via urine. However, the body will compensate this effect by a higher absorption of calcium, i.e. the amount of calcium that stays in the body. On the other hand, several studies have shown that people with high intakes of proteins (especially dairy products) have a higher bone mass than consumers with lower intakes.