Some preliminary evidence suggests that omega-3 fatty acids could reduce the risk of kidney stones or at least reduce oxalate levels in the body, which when elevated can increase the risk of a kidney stone. A total of 15 healthy individuals (7 women, 8 men) with an average age of 28 years were included in the study. Participants who had no history of stones or other medical conditions were followed for 30 days of testing. They ingested fish oil supplements with a total omega-3 content of 1500 mg (combination of 900 mg EPA and 600 mg DHA) per day. Upon completion of the 30-day fish oil supplementation, the study participants showed a significant reduction in oxalate levels. Presumably, the risk of calcium binding with oxalate in their bodies and forming a kidney stone was therefore reduced as well. Urinary calcium excretion and other urinary variables did not change significantly with use of the dietary supplement.
The study suggests that calcium oxalate kidney stone formers could benefit from ingesting more omega-3 fatty acids. Fish oil supplements are some of the best selling supplements in both the United States and Canada because they actually have some positive overall health data, but perhaps also because they have received a good deal of media hype and are misunderstood. Fish oil probably has a positive role for those at a higher risk of heart disease and to reduce triglycerides (this use is FDA approved). Routinely, it is a positive sign when a supplement has both a pharmaceutical and over-the-counter option available and fish oil is a classic example. However, prescription fish oil is expensive and the over-the-counter options are dropping in price quite rapidly, perhaps making that a better option for some patients.
One other indicator of fish oil’s positive role in reducing kidney stones—recent results from the US DASH diet study showed that an intervention to promote heart health through multiple dietary changes also resulted in a large reduction in kidney stone risk. Participants in that study were encouraged to increase their consumption of fatty, oily fish (not fried). This may indicate that dietary fish oil, as well as fish oil supplements, shows promise in reducing kidney stone formation. Possibly one more good reason to increase your consumption of salmon, tuna, herring, anchovies, or sardines! Talk to your doctor to see if eating more fish or fish oil supplements make sense for you.
The Bottom Line
New research suggests that even 1 to 2 fish oil pills per day could reduce the risk of developing a kidney stone. Talk to your doctor, particularly if you are at higher risk of having a kidney stone.
Siener R, Jansen B, Watzer B, Hesse A. Effect of n-3 fatty acid supplementation on urinary risk factors for calcium oxalate stone formation. J Urol 2011, 185:719–724.
Yasui T, Suzuki S, Itoh Y, et al. Eicosapentaenoic acid has a preventive effect on the recurrence of nephrolithiasis. Urol Int 2008, 81:135–138.
Mark A. Moyad, MD, MPH, is the primary author of over a hundred medical articles and numerous books. He maintains a consulting practice on complementary medicine at the University of Michigan Medical Center, Department of Urology.