Daily calcium plus vitamin D supplements may increase the risk of kidney stones

Dietary supplements of calcium and vitamin D may increase the risk of developing urinary tract stones, according to a new US study.

In the randomized controlled trial, data from 36,282 postmenopausal women receiving either 400 IU of vitamin D and 1,000 milligrams of calcium carbonate per day or a placebo for an average of seven years were analyzed (1). At the end of the study period, the researchers reported that calcium plus vitamin D supplements were associated with a 17 percent increase in the incidence of urinary tract stones, compared with the placebo.

However, experts commented that the public health benefit of preventing bone fractures by supplementing vitamin D plus calcium would outweigh the potential risk of developing kidney stones.

1. Wallace R. B. et al. Urinary tract stone occurrence in the Women's Health Initiative (WHI) randomized clinical trial of calcium and vitamin D supplements. American Journal of Clinical Nutrition. 2011; 94(1):
   270–277.