TREATMENT OF IGA NEPHROPATHY WITH OMEGA-3-POLYUNSATURATED FATTY-ACIDS - A PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED STUDY

In several studies diets supplemented with fish oil containing a high proportion of omega-3-polyunsaturated fatty acids (w-3-PUFA) have been shown to produce beneficial effects, such as a reduction in blood pressure, lipid levels and inflammation, all of which may affect the course of IgA nephropathy. However, the results of hitherto published studies concerning IgA nephropathy have been inconclusive. We therefore carried out a prospective, randomized, placebo-controlled six-month study with a higher daily dose of w-3-PUFA than used in previous studies. Thirty-two adult patients with biopsy-proven IgA nephropathy and proteinuria completed the study: 15 were assigned to a fish-oil product with a high percentage of w-3-PUFA (K 85, with 55% eicosapentenoic and 30% docosahexenoic acid) and 17 to corn oil, 6g daily of either oil. At the start, no significant differences were found between the two groups (K85: 3 females/12 males, mean age 39 years (range 22-64), corn oil: 4 females/13 males, age 42 years (range 26-68). By six months, supplements of K85 resulted in a slight but significant reduction in glomerular filtration rate (GFR) compared to the start: Cr-51-EDTA: 63 +/- 22 to 59 +/- 21 ml/min/1.73m(2) (p <0.05), creatinine clearance: 91 +/- 31 to 79 +/- 25 ml/min (p <0.01), s-creatinine: 131 +/- 39 to 139 +/- 39 mu mol/l, whereas no change in GFR was observed in the corn oil group. The urinary total protein and red blood cell excretions were not affected in any of the groups. At the start, most of the patients had mildly- to moderately elevated plasma total and LDL cholesterol (C) levels, about half of them having elevated levels of triglycerides (TG). K 85 supplements led to a significant (p < 0.05) fall of TG (-18%), increase of LDL-C (+11%) and increase of ApoB (+8%). Corn oil supplements led to a significant (p <0.01) increase in HDL-C (+22%). We conclude from the results of this study that patients with IgA nephropathy with proteinuria and moderately reduced GFR do not benefit from treatment with high doses of w-3-PUFA regarding protein excretion and progression of renal failure.