calcium supplementsCalcium supplements may increase the risk of kidney stone recurrence, according to a study that will be presented at ASN Kidney Week 2015 November 3¬–8.Patients who took calcium supplements had lower total calcium and oxalate (which are components of kidney stones) in their urine while blood levels were unaffected. However, these patients also had a faster rate of kidney stone growth suggesting that the mechanism of calcium supplementation on stone formation may not be straightforward. Vitamin D supplementation also decreased urinary calcium excretion as well as stone growth, suggesting that it may help prevent the risk of stone formation.
“While taking supplemental calcium has associated positive effects, these results suggest that supplemental, as compared with dietary, calcium may worsen stone disease for patients who are known to form kidney stones,” said Loftus.

Source Newsroom: American Society of Nephrology (ASN)
Studies: “Effects of Calcium and Vitamin D Supplementation on Known Stone Formers”