Wild vs. Farmed Salmon

Although farmed salmon tends to be higher in omega-3 fatty acids than wild salmon, it also has much higher levels of chemical contaminants that may cause cancer and neurobehavioral changes in children. Farm raised salmon also has about ¼ the amount of Vitamin D than wild salmon (3). For these reasons, many people choose wild over farmed salmon.

Researchers from the Midwest Centre for Environmental Science and Public Policy conducted a benefit-risk analysis of eating wild versus famed salmon. Overall, they found that wild Pacific salmon is safer than farmed Atlantic salmon in terms of chemical contaminants. They noted that if farmed salmon is chosen, Chilean salmon tends to have the lowest levels of pollutants, whereas Scottish farmed salmon has the highest levels. The benefit-risk analysis showed that farmed fish from Scotland, Norway, and Eastern Canada should be eaten a maximum of three times per year; farmed fish from Maine, Washington and Western Canada a maximum of three to six times per year; and Chilean farmed fish no more than six times per year. Wild salmon on the other hand can be consumed more often than farmed- about once a week for chum salmon, and twice per month for pink, Sockeye, and Coho (2).

Another study published in the Journal Environmental Health Perspectives reported that levels of PCBs, toxaphene, dioxins and other contaminants are found in much higher levels in farmed salmon than wild pacific salmon (1).

So, although it may be safe to eat farmed salmon occasionally, children and pregnant women should avoid eating farmed salmon. If available, wild salmon is a safer choice.

References

1. Foran et al. (2005). Risk-based consumption advice for farmed Atlantic and wild Pacific Salmon contaminated with dioxins and dioxin-like compounds. Environ Health Perspec.; 113(5): 552-6.
2. Foran et al. (2005). Qualitative analysis of the benefits and risks of consuming farmed and wild salmon. J Nutr.; 135(11): 2639-43.
3. Lu et al. (2007). An evaluation of the vitamin D3 content in fish: Is the vitamin D content adequate to satisfy the dietary requirement for vitamin D? J Steroid Biochem Mol Biol; 103(3-5): 642-4. Epub 2007 Jan 30.