A urinary detergent and urolithiasis

Does fish oil benefit stone formers?

The possibility that dietary fish oil supplementation may benefit patients with hypercalciuric urolithiasis by decreasing calcium excretion and enhancing protective mechanisms has been studied in rats and humans. In experiments on rats in metabolic cages, fish oil inhibited experimental nephrocalcinosis induced by intraperitoneal calcium gluconate. There were no significant changes in urinary biochemistry. In a clinical study on 18 hypercalciuric recurrent stone patients fish oil significantly decreased urinary calcium excretion. This effect was accompanied by decreases in the excretion of magnesium and citrate. Oxalate excretion and urinary fibrinolytic activity were unchanged. Overall, fish oil had a limited impact on the risk profile for recurrent urolithiasis.

Do stone formers have lower urinary fibrinolytic activity than controls?

A comparison of urinary fibrinolytic activity between 31 stone formers and 50 controls failed to demonstrate any significant difference and so failed to confirm an earlier independent observation. This may be due to methodological and design differences between the 2 studies, but does suggest reservations about the significance of lowered urinary fibrinolytic activity as a risk factor for renal stone disease. Dietary information from those taking part in the study suggests that a reduction of meat intake by stone formers might be associated with increased urinary fibrinolytic activity. This might account for the discrepancy between the 2 studies, in which case this observation could be of significance.