James V. Donadio's publication of a paper on the long-term outcome of IgA nephropathy patients treated with fish oil immediately caught the attention of the kidney community in August, 1999. Given Donadio's association with the prestigious Mayo Clinic, many patients believed this was credible evidence of a non-pharmacological way to slow the downward progression of kidney disease. While the jury is still out on the long-term benefits of high-dose fish oil, many nephrologists recommend fish oil supplements for patients with IgA nephropathy and similar kidney diseases.
Benefits
Based upon a mean follow up period of 6.4 years, Donadio showed that the eight year renal survival rate for research subjects taking fish oil was 85 percent. Subjects taking a placebo had only a 56 percent renal survival rate. This means that only 15 percent of Donadio's subjects taking fish oil reached end-stage renal disease, compared to 44 percent of the controls. Given this data, Donadio concluded that fish oil supplementation retards progression of IgA nephropathy.
Other Research
While Donadio's work has not been replicated, other researchers also studied the effect of fish oil in patients already on dialysis and who have been transplanted. Nephrologists are particularly interested in learning whether fish oil can minimize the toxicity of cyclosporine, an immunosuppressant used in transplant patients. Although large long-term studies have not been performed, the research is modestly encouraging.
Dosage
The active ingredients in fish oil are the omega-3 fatty acids docosahexanoic acid and eicosapentanoic acid. Donadio's research subjects received 1.9 g of eicosapentanoic acid and 1.4 g of docosahexanoic acid. The amount of these fatty acids in different brands of fish oil varies widely. However, for many brands, this means taking a total of 12 g of fish oil.
Warning
Never confuse fish oil with cod liver oil. Whereas fish oil is made from the bodies of whole fish, cod liver oil is made from the livers of codfish. Nutritionally, these supplements are very different. Cod liver oil so rich in vitamin A that it can easily cause vitamin A toxicity if taken in the high doses recommended for fish oil supplementation.
References
- "Journal of the American Society of Nephrology;" The Long-Term Outcome of Patients with IgA Nephropathy Treated with Fish Oil in a Controlled Trial; James V. Donadio; Aug. 1999
- "Transplantation: The Effects of Dietary Supplementation with Fish Oil on Renal Function in Cyclosporine-Treated Renal Transplant Recipients.
- "Transplantation;" The Effects of Dietary Supplementation with Fish Oil on Renal Function in Cyclosporine-Treated Renal Transplant Recipients.
- Foundation for IgA Nephropathy: Fish Oil
