Fish Oil Contaminated with Persistent Organic Pollutants Reduces Antioxidant Capacity and Induces Oxidative Stress without Affecting Its Capacity to Lower Lipid Concentrations and Systemic Inflammation in Rats

Background: Numerous studies have investigated the benefits of fish, fish oil, and omega-3 (n-3) polyunsaturated fatty acids against cardiovascular diseases. However, concern surrounding contamination with persistent organic pollutants (POPs) prompts caution in the recommendation to consume fish and fish oil. Objective: The present study compared the effects of fish oil contaminated with polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) on serum lipid profiles, inflammation, and oxidative stress. Methods: Twenty eight-day-old male Sprague-Dawley rats (n = 30) consumed diets of unmodified fish oil (FO) consisting of 15% fat by weight, persistent organic pollutant-contaminated fish oil (POP FO) (PCBs at 2.40 mu g/g; OCs at 3.80 mu g/g FO), or corn oil (control; CO) for 9 wk. Lipid profiles and C-reactive protein concentrations were assessed. Hepatic gene expression related to lipid metabolism was determined by real time quantitative polymerase chain reaction analysis. Results: After 9 wk of feeding, accumulation of PCBs and OCs in the fat tissue of the POP FO group compared with the other 2 groups was confirmed (P < 0.01). Both fish oil groups showed greater HDL cholesterol (FO 53 +/- 5.3 and POP FO 55 +/- 7.7 vs. CO 34 +/- 2.3 mg/dL), but lower triglycerides (24 +/- 2.8 and 22 +/- 3.0 vs. 43 +/- 5.6 mg/dL), LDL cholesterol (38 +/- 14 and 34 +/- 9.2 vs. 67 +/- 4.4 mg/dL), and C-reactive protein (113 +/- 20 and 120 +/- 26 vs. 189 +/- 22 mu g/dL) compared with the CO group (P< 0.05). Gene expression of fatty acid synthase in both fish oil groups was also less than in the CO group (P< 0.05). However, the POP FO group showed greater lipid peroxidation (5.1 +/- 0.7 vs. 2.9 +/- 0.9 and 2.6 +/- 0.6 mu M) and less antioxidant capacity (0.08 +/- 0.06 vs. 0.5 +/- 0.1 and 0.4 +/- 0.1 mM) than the CO and FO groups (P < 0.05). Conclusions: These findings indicate that, despite exhibiting benefits on serum lipid concentrations and inflammation, contamination with PCBs and OCs showed significant negative effects on oxidative stress and antioxidant capacity in rats. Future studies should investigate the effects of different contaminant doses and the possibility of a dose-dependent response, a lengthened feeding time, and interactions between contaminant mixtures and oils of varying composition to advise on dietary consumption of fish and fish oil.