PARMA, ITALY. Kidney stones, in at least 70 per cent of all cases, consist of calcium oxalate crystals, often mixed with calcium phosphate or sodium urate. The prevailing medical practice is to prescribe a low- calcium diet in order to prevent recurrence of stones. Italian researchers now question this approach. Their randomized clinical trial included 120 men with a history of kidney stones (idiopathic hypercalciuria). Sixty of the men were assigned to a low-calcium diet (avoidance of milk, yogurt and cheese) while the other sixty were assigned to a normal calcium diet that was low in animal protein (52 grams/day max.) and salt.
After five years 23 of the men in the low-calcium diet group had experienced a recurrence of kidney stones
as compared to only 12 men in the normal calcium diet group. Thus the men in the low-calcium group had
twice the risk of recurrence than did the men in the normal calcium, low protein and low salt group. Says Dr.
David Bushinsky of the University of Rochester, "Physicians should no longer prescribe a low-calcium diet to
prevent recurrent nephrolithiasis in patients with idiopathic hypercalciuria".