Ever since James Donadio, MD, published his 1999 paper about the benefits of fish oil for patients with IgA nephropathy, patients with all types of chronic kidney disease have sought more information. Donadio's paper suggested that fish oil retarded the progression of IgA nephropathy, a disease that can end in renal failure. Writing from the Mayo Clinic, Donadio's work had a blush of credibility that other claims lack. While the jury is still out, many nephrologists suggest that patients with chronic immunologically mediated kidney diseases take fish oil.
Never confuse fish oil with cod liver oil. While fish oil may be beneficial, cod liver oil can be toxic because it contains high concentrations of vitamin A. This is particularly problematic for patients with kidney damage. Packages of fish oil and cod liver oil are labeled very differently. Fish oil containers never include the phrase "cod liver oil." Kidney patients should steer clear of cod liver oil until they consult their nephrologists.
After Donadio's paper appeared, studies in everything from rats to transplant patients examined the possible benefit of supplementation with fish oil. While many of these results look promising, studies are often small and the results are not conclusive. However, many nephrologists believe that supplementation with fish oil has no dangers, so they recommend fish oil to their patients.
Omega-3 Fatty Acids
Fish oil contains a mixture of omega-3 fatty acids. With respect to kidney disease, the important omega-3s are eicosapentanoic acid and docosahexanoic acid, which are abbreviated EPA and DHA, respectively. Although standard dosages of fish oil have never been established, many people look to the Donadio paper for guidance. Donadio's 1994 Mayo Clinic trial report involves dosing patients with 1.8 g of EPA and 1.4 g of DHA. While the EPA and DHA content of different fish oil brands varies, many patients find that 6 g of fish oil twice a day had the necessary amounts of these fatty acids.
The Foundation for IgA Nephropathy notes that fish oil can increase the anti-platelet activity of aspirin, ibuprofen and other non-steroid anti-inflammatory drugs. While you should always discuss taking any drug or supplement with your nephrologist, this is doubly important if you take aspirin regularly. Your nephrologist may be able to adjust doses so that you get the maximum possible benefit with the least possible risk.