The wisdom of that advice was confirmed by a new analysis from the Women’s Health Initiative (WHI), involving more than 78,000 women over 50. It used to be thought that calcium increased the risk because most stones contain the mineral, but research has shown that dietary sources are actually protective.
In contrast, calcium supplements (especially when taken without food) may increase the risk slightly, according to previous WHI data and some other research.
Thus, women who tend to form stones and take calcium should talk to their doctors about stopping the pills. Animal protein, once thought to also increase the risk, was not associated with kidney stones.