Effects of eicosapentaenoic acid on urinary calcium excretion in calcium stone formers

The low incidence of atherosclerosis and other degenerative disease, including urolithiasis, in the Greenland Eskimo has been attributed to their high consumption of oily fish with its high concentration of eicosapentaenoic acid (EPA). With a westernized diet, the oxygenated products of renal prostaglandin synthesis are metabolites of the n-6 series and these are known to play important roles in several pathophysiological processes involved in calcium stone formation. Buck's group presented a hypothesis that the initiating factor for lithiasis triggers prostaglandin synthesis, and showed that this influenced by EPA treatment.

In order to ascertain the effects of EPA on plasma lipids and urinary parameters, we undertook a clinical study whereby a highly purified preparation was administrated (1,800 mg/day) to 88 patients with urinary stones for 3 months (short term) and 18 months (long term).

Hyperlipemia improved the affected individuals and urinary calcium was significantly reduced in the hypercalciuric but not in the normocalciuric group.

The results suggest that EPA by reducing urinary calcium might favorably affect urine composition in a way that possibly reduces the risk of calcium stone formation.