Fish Oil for Kidneys

Chronic kidney disease can be a long and depressing haul, which is why James V. Donadio's 1999 paper on the benefits of fish oil raised the hopes of the kidney community. Donadio's research showed that long-term supplementation with fish oil slowed the progression of IgA nephropathy, a chronic kidney disorder that can end in renal failure.

Limitations

As of March 2011, there have been no meta-studies on the effect of fish oil on kidney disease. While the research is mildly encouraging, it focuses on many different areas such as patients on dialysis, post-transplant patients, lipid profiles of patients and animal studies. Donadio's original long-term study has not been replicated.

Active Ingredients

Fish oil is a rich source of the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid, abbreviated EPA and DHA, respectively. Donadio's research subjects took enough fish oil to provide 1.9 g of EPA and 1.4 g of DHA per day. While different preparations of fish oil have different amounts of EPA and DHA, for many patients, this means taking 12 capsules of fish oil per day.

Speculation

Research suggests that fish oil minimizes inflammation. While inflammation is not the only factor underlying the progression of IgA nephropathy, it does play a significant role, which is why fish oil might slow the progression of this and other chronic kidney diseases. In a 2002 paper, P.C. Calder at the University of Southampton noted that studies in humans and animals show that fish oil blunts the inflammatory response so effectively that it may be useful in treating rheumatoid arthritis.

General Applicability

While Donadio's research was focused only on patients with IgA nephropathy, patients with other chronic kidney diseases such as MPGN and FSGS began asking their nephrologists if it would be safe to take fish oil supplements, along with their conventional treatment. To date, there is no published data on how fish oil affects the course of these diseases. Part of the reason for the lack of data is that these diseases affect small populations of patients. Moreover, it is difficult to distinguish the effects of conventional treatments vs. fish oil.

Warning

Kidney patients should not take fish oil without consulting their nephrologists. While fish oil is generally harmless, it might interact with aspirin and other common over-the-counter drugs. This might be problematic if you are taking daily aspirin to reduce the risk of heart attack or stroke. Moreover, fish oil may inhibit the immune system, which might be an issue for patients who are already taking immunosuppressants.