July 31, 2003 -- Farmed salmon are dangerous, a small study suggests. But the FDA says you shouldn't change your eating habits just yet.
A public service organization, the Environmental Working Group (EWG), says farm-bred salmon are contaminated with high levels of PCBs, a kind of dioxin. PCBs have been banned in the U.S. since 1976 because -- in very small concentrations -- they are thought to cause cancer and birth defects. Despite the ban, PCBs linger in the environment.
The watchdog group bought 10 salmon filets in grocery stores in Washington, D.C.; Portland, Ore.; and San Francisco. Lab analysis showed "high" PCB levels in seven of the 10 samples. All but one came from North American fish farms; the seventh and most polluted filet came from a Scottish farm.
Would it be dangerous to eat the fish? That depends on whom you ask. Environmental Working Group Senior Scientist Kristina Thayer, PhD, notes that these PCB levels are 4.5 times higher than the limits set by the Environmental Protection Agency for weekly wild fish consumption. The EPA says a person shouldn't eat wild fish with such high PCB levels more than once a month.
Bought vs. Caught
But the farm-raised fish were bought, not caught. That means they aren't regulated by the EPA, but by the Food and Drug Administration. And the FDA's standards are 500 times less protective than the EPA guidelines. So PCB levels in farmed salmon are actually well within legal limits.
Does this mean they're safe? Again, that depends on whom you ask.
"It is troubling," Thayer tells WebMD. "The recommendations from the EPA come from concerns about cancer. I buy wild salmon when I can. Why take the chance? They developed those recommendations for a reason. I would rather stack the deck in my favor."
But the FDA sticks by its standards.
"Salmon is a healthy food and should be part of a healthy diet," an FDA spokesperson tells WebMD. "We recommend salmon consumption not be altered."
Meanwhile, the spokesperson says, the FDA will consider the study and other scientific reports as its dioxin-monitoring program continues.
Bill Demmond is vice president of Atlanta-based Inland Seafood, a large-scale wholesale food distributor.
"More and more farmed fish are coming in the future -- it's not going to be just salmon," Demmond tells WebMD. "Contaminants are a big issue. But the benefit you get from eating the seafood far outweighs the concerns. I would eat farmed salmon more than once a month and feed it to my wife and my children."
Alex Trent is spokesman for Salmon of The Americas, a newly formed trade group representing 80 salmon farms in the U.S., Canada, and Chile. He says that he's glad the EWG study showed that farmed salmon are well below FDA guidelines. And he argues that the stricter EPA guidelines aren't meant for consumers, but for populations such as Native American tribes that get most of their protein from fish caught in polluted waters.
"According to EPA guidelines a person could only drink one six ounce glass of milk every other day, if you hold milk to the salmon standard," Trent tells WebMD. "The EWG is right when they say that farmed salmon has more PCBs than beef. But if you compare per capita beef and salmon consumption, even a heavy salmon consumer gets half the PCBs from salmon he gets from beef."
Where Salmon Get Their PCBs
Farmed salmon eat fish meal. It's a special food made from small fish. These small fish often are caught in polluted waters. And since farmed salmon are deliberately fattened with a diet rich in fish oil, they store PCBs in their fat at 20 to 30 times the concentration found in fish meal.
Three independent tests of 37 samples of fish meal from six different countries found PCBs almost every time.
Farmed salmon have 52% more fat than wild salmon, the EWG notes. Per ounce of fat, they have fewer of the healthy omega-3 fats than their wild cousins. A small Canadian study found that farmed salmon have five times higher PCB levels than wild salmon.
Trent says the salmon-farming industry is actively working to lower PCB levels in fish meal. He says -- and the FDA agrees -- that PCB levels in farmed salmon have actually gone down over the past few years.
Thayer says that science is only now beginning to realize how dangerous PCBs can be. She warns consumers not to be fooled into thinking very small amounts of these chemicals pose no threat.
"Look at the hormones in our body -- biologically active levels are measured at the parts-per-trillion level," she says. "Small amounts of chemicals with hormone-like function -- PCBs -- can be active in the body. And PCBs are something that we can't easily eliminate from our bodies."
What to Do
Thayer says it's not necessary to stop eating farm-raised salmon. Here are the EWG's recommendations for consumers:
- When possible, choose wild salmon over farmed salmon.
- Eat an 8 oz. portion of farmed salmon no more than once a month.
- Trim fat from farm-raised salmon before cooking.
- Cook farm-raised salmon in ways that let the fat run off. Grill, broil, or bake. Don't fry or sauté.