A composition and method of treating patients diagnosed with NAFLD is disclosed. The composition contains n-3 polyunsaturated fatty acids (PUFAs) for treatment of NAFLD patients, wherein the amount of PCB 153 in the composition has been minimized. The composition is administered to a patient in a sufficient amount and for a sufficient time to increase the level of n-3 PUFAs or to correct a deficiency of n-3 PUFAs in the patient's blood. The method increases the level of n-3 PUFAs without contributing to the body burden of PCB 153.