Oxalate, not calcium, may be culprit in forming kidney stones.
People who consumed the most dietary calcium from food had a 20 percent lower chance of developing kidney stones than those who consumed the least calcium, says a study reported in the Journal of Urology.
This seems contrary because most kidney stones are made from calcium oxalate. Researchers suspect that oxalate, not calcium, is the real culprit. They theorize that oxalate binds with calcium. Therefore, more calcium means more oxalate is removed — before it is absorbed in the bloodstream and causes problematic stones.
Dr. Eric Taylor, a kidney specialist at Maine Medical Center in Portland, was the lead author of the study. Taylor and colleagues analyzed data from three studies.
Source: https://www.jurology.com/article/S0022-5347%2813%2903862-7/abstract