Weighing the Benefits and Risks of Eating Farmed Salmon

Farmed salmon is getting yet another grilling this summer. Reports in an environmental journal once again suggest that contamination with "chemicals" (this time including fire-retardant chemicals) makes salmon a less than healthy food.

There are many, however, who beg to differ.

Earlier this year, Science magazine published a piece raising concerns about trace levels of chemicals like PCBs in farmed salmon and going so far as to suggest that consumption of this food be limited to avoid risk. Science just recently published three letters from scientists responding to the charges and recommendations. In summary, all three letters express skepticism about the claims that farmed salmon poses a human health risk -- and emphasize that if any hypothetical risks do exist, they are far outweighed by the known health benefits of eating salmon.

Specifically, Christopher Rembold from the University of Virginia wrote that the original Science report "may have unintended negative consequences on human health," since by not eating salmon people would be denied the benefits of omega-3 fatty acids (also see the FactsAndFears piece on how the anti-fish hype clashes with new Dietary Guidelines).

Rembold went on to point out that the EPA guidelines for contaminants, on which the report relied, "are estimates from nonhuman toxicity...[T]here is no clinical trial showing that these toxins, when given to humans, causes cancer."

In another letter (signed by a number of scientists from Norway), the correspondents noted that wild salmon is not generally available in Norway -- and thus Norwegian citizens eat a significant amount of farmed salmon. They note that data from the Cancer Registry of Norway indicates "the relative risk for cancer was not increased among women having a higher self-reported consumption than among those with less than the recommended intake. We found no indication of a dose response."

The bottom line: these scientists strongly urge you not to give up eating farmed salmon. It is a healthy, nutritious part of a balanced diet. Beware advocates and their statistics when they inflate hypothetical risks and ignore health benefits.

Dr. Elizabeth M. Whelan, Sc.D., M.P.H., is president of the American Council on Science and Health. Also see articles by Gousse and Kava on the latest omega-3 fatty acids study and the role of fish in new Dietary Guidelines, respectively.

A RESPONSE (to see more reader responses, if any, or to add one, sign in at the right margin):

At the last minute before going out the door, I read Beth's article on farmed salmon this morning. I am on my way to Costco to buy more of that delicious farmed salmon from the East Coast. We eat it all of the time and it's often a centerpiece for when we have dinner guests. Stop by sometime and join in!!

BTW, the list of natural occurring pesticides (organo halides) maintained by Dr. Gordon Gribble, is now over 3000. Many of these are found in the sea, including seaweeds. Thus, when discussing "pollution" and "pesticides" in our food, it's essential to discuss the background levels from natural sources.

Second, thanks to the technological advances in detection of these materials it's routine to measure constituents "pollutants" in samples at the parts per trillion levels. Thus, the mere detection of such substances doesn't imply harm to the organism, such as us humans.

Third, in order to claim harm from a "pollutant" a considerable amount of toxicology needs to be performed. Dose response curves and other tools of toxicology are invaluable when they are available. They usually aren't, which makes the scare stories a series of assertions, typically wrong. Keep up the good work.

--Mike Fox