In a study related to health risk or benefit analysis it has been found that unless heart disease is a risk factor wild salmon is better than farmed salmon .
The reasoning put forth is that although farmed salmon is richer in omega 3 fatty acids it also has a large amount of chemical contaminants.
These chemicals are known to be a cause of cancer, memory impairment and neurobehavioral changes in children.
The study is credited to Barbara Knuth, Cornell professor of natural resources and Steven Schwager, Cornell associate professor of biological statistics and computational biology.
In the words of Dr. Knuth and Dr. Steven, "For a middle-aged guy who has had a coronary and doesn't want to have another one, the risks from pollutants are minor ones, and the omega-3 benefits him in a way that far outstrips the relatively minor risks of the pollutants. But for people who are young -- and they're at risk of lifetime accumulation of pollutants that are carcinogenic -- or pregnant women -- with the risks of birth defects and IQ diminution and other kinds of damage to the fetus -- those risks are great enough that they outweigh the benefits.
Because we found regional differences in contaminants in farmed salmon, with Chilean salmon showing the lowest levels and European (particularly Scottish) farmed salmon showing the highest levels, careful consumers with a history of heart disease could choose farmed salmon from Chile for their high omega-3 content and relatively lower level of contaminants."
Also in the study the researchers revealed that the levels of chlorinated pesticides, dioxins, PCBs and other contaminants are up to 10 times greater in farm-raised salmon than in wild Pacific salmon, and that salmon farmed in Europe are more contaminated than salmon from South and North American farms.
So they advocate intake of wild salmon over farmed ones.