Examining Changes in Persistent Organochlorine Pollutants Following High Consumption of Farmed Atlantic Salmon: Results from an 8-Week Dietary Intervention Study

Abstract

Background: In 2004 a publication in Science by Hites et al. reported a 10 to 100-fold higher concentrations of persistent organochlorine pollutants (POPs) in farmed Atlantic salmon compared to wild Pacific salmon. These findings generated intense debate on the health-risk-benefits of farmed Atlantic Salmon.Objective: To examine the short-term effect of high consumption of farmed Atlantic salmon on serum POP concentrations.Methods: A 4-arm randomized controlled trial in overweight or obese subjects (BMI: 27.5-32.5 kg/m2) assigned to energy-restricted seafood diet over an 8-week period (SEAFOOD-plus, 2004-2005, n=324). Controls were assigned to a fish free diet and one arm was assigned to three meals per week of farmed Atlantic salmon (24 meals), matched for energy. Of these participants 20 male cases (Salmon) and 20 male controls were selected who experienced modest weight loss and concentrations of pp-DDE, HCB and PCBs (congeners no. 118, 138, 153, 170, 180) were measured at baseline and endpoint.Results: Median baseline concentrations for sum of PCBs, pp-DDE and HCB were 1.41, 0.78 and 0.16 ng/mL, respectively. Mean weight loss at endpoint was 4.8kg and 4.5kg in the salmon and control group (p=0.68), respectively. Concentrations of EPA and DHA were significantly increased at endpoint by ~32% in the Salmon group but reduced by ~14% in controls, suggesting compliance to the intervention. At endpoint the mean sum of PCBs was increased by 0.36ng/mL in the salmon group (p=0.22). Lack of significance is unlikely to be explained by weight loss during the intervention as only a minor change of -0.06ng/mL (p=0.84) in PCB concentrations were observed among controls. Individual PCB congeners, pp-DDE and HCB were non-significantly but systematically increased by 6 to 41% of mean levels in the salmon group compared to controls.Conclusion: Our study suggests that high consumption of farmed Atlantic Salmon over a short period does not substantially affect circulating POP levels.