Effects of dietary calcium, magnesium and phosphorus on the formation of struvite stones in the urinary tract of rats.

After feeding various diets we studied the effects of dietary calcium, magnesium and phosphorus on the formation of struvite stones in rats with urinary tract infections, and also studied the effects of the administration of vitamin D3 and aluminium gel on stone formation. A low-magnesium diet decreased urinary magnesium and prevented stone formation, but a medium-calcium diet did not significantly decrease stone weight. A high-calcium diet decreased urinary phosphorus and inhibited stone formation. A high-calcium and high-phosphorus diet decreased urinary excretion of magnesium and inhibited stone formation. Although the administration of vitamin D3 did not inhibit stone formation, aluminium gel decreased the urinary level of phosphorus and prevented stone formation. A marked decrease in urinary magnesium and/or phosphorus may prevent struvite stone formation in rats with urinary tract infections.