A daily dose of fish oil slows the progression of kidney disease. A Mayo Clinic study, reported the Journal of the American Society of Nephrology, showed that people suffering from IgA nephropathy who took the fish oil had significantly better kidney function. The report shows that the benefits of fish oil continue over time. Researchers followed all 106 of the original study participants for an average of more than six years. Significantly fewer of the participants taking fish oil suffered advanced kidney failure than people who took a placebo. The group taking the fish oil also had better kidney function than the placebo group.