Salmon has become a staple of the American diet in the last 10 years thanks to farm-raised salmon, which is cheap, plentiful and available year-round, but a new study cautions that the farm-raised fish contain considerably higher levels of cancer-causing PCBs and other pollutants than salmon caught in the wild.
In the study, which was published in Science magazine, the authors said people might want to curtail their consumption of farm-raised salmon.
The researchers concluded that, "Although the risk/benefit computation is complicated, consumption of farmed Atlantic salmon may pose risks that detract from the beneficial effects of fish consumption."
A Health Quandary
Health experts recommend eating at least two servings of baked or grilled fish each week. Salmon is popular because it is rich in heart-healthy omega-3 fatty acids.
The study follows on the heels of a similar report released last summer by the Environmental Working Group that recommended that consumers eat an 8-ounce portion of farmed salmon no more than once a month.
PCBs or Polychlorinated Biphenyls are a family of chemicals that once had hundreds of industrial uses, such as the manufacturing of paint, plastic and rubber products. Congress banned PCBs in the late 1970's due to concern over their toxicity and persistence in the environment.
The PCB levels in farm-raised salmon measured in the study did not exceed federal limits and experts said Americans should not be quick to cut the fish out of their diets.
Officials at the Food and Drug Administration said they had looked at all the data and their advice to consumers was not to alter their consumption of farmed or wild salmon.
Preventing the Problem
Alex Trent, executive director of Salmon of the Americas, a trade group representing salmon farmers in Chile, Canada and the United States, said the critical reaction spoke louder than anything his organization could say.
"Unfortunately, even these authorities can't prevent detrimental effects the negative publicity may have on consumption of farmed salmonone of the most nutritious foods available," he said.
Trent also noted that the samples in the study were obtained two years ago and in that time PCB levels in farmed salmon had decreased significantly because of continuing industry efforts.
PCBs are in the fishmeal and oil fed to farm-raised salmon and the industry is trying to reduce the amount of toxins by substituting vegetable feed.
Should you Choose Farm-raised or Wild?
Science aside, how can you tell which salmon is farmed and which salmon is wild when you're standing at the fish counter? Farm-raised salmon is usually tagged "Atlantic" or "Icelandic," while wild salmon is labeled as such or called "Alaskan." When in doubt, ask your fishmonger
Unless it's frozen, wild salmon is only available from mid-May through late September when the fish spawn. Prices vary for wild and may either be comparable to farmed, or substantially more expensive.
If you're buying farm-raised salmon, ask your fishmonger where it comes from. The study found that chemical concentrations were highest in farmed salmon from Scotland and the nearby Faroe Islands and lowest in farmed salmon from Chile and Washington State. But even the least contaminated salmon contained a lot more PCBs and other pollutants than wild salmon. The report called for labeling salmon as farmed and listing the country of origin.
PCBs accumulate in the skin and the fat of salmon, so experts recommend trimming your fish before cooking. Also, broil, bake or grill your salmon instead of using other methods because these are the surest ways to cook off any remaining fat.