Eicosapentaenoic acid (EPA), which is purified from fish oil, attenuates inflammatory responses by decreasing eicosanoid and cytokine production. EPA reportedly improves renal survival in patients with immunoglobulin (Ig)A nephropathy; however, this is unconfirmed.

We studied the effects of EPA on IgA nephropathy patients. Eighteen biopsy-confirmed IgA nephropathy patients (aged 31 +/- 3 years) were enrolled. The prognoses based on glomerular findings were good (N = 5), relatively poor (N = 12), and poor (N = 1). EPA was administered at 1.8 g/day for 12 months. Five biopsy-confirmed IgA nephropathy patients were enrolled as control subjects. Administration of other drugs used to treat IgA nephropathy was not changed. The estimated creatinine clearance (eCCr), serum creatinine (Cr) concentration, urinary protein creatinine ratio (U/P), and other clinical parameters were checked. In the EPA group, the Cr went from 0.8 +/- 0.2 mg/dL to 0.7 +/- 0.2 mg/dL after 12 months of EPA treatment, and the U/P went from 550 +/- 580 mg/g Cr to 330 +/- 920 mg/g Cr.

The values did not differ significantly; however, Cr and U/P tended to improve, with no adverse effects from the EPA. The eCCr improved significantly (99 +/- 7-110 +/- 8 mL/min, P = 0.001) in the EPA group, but not in the control group (126 +/- 12-120 +/- 13, P > 0.05). The effect of EPA in patients with IgA nephropathy is not pronounced, but these results suggest that EPA is a safe and worthwhile supplement to the drugs used to treat this disease.