= Full article available- Farming makes salmon cheap, plentiful—but at what cost?
- High levels of PCBs in farmed salmon
- Farmed salmon a threat to health?
Salmon is high in the omega-3 fatty acids that scientists say are good for the heart and may even help protect against rheumatoid arthritis and other illnesses. And farm-raised salmon is easier to get than wild. It’s $4 to $5 cheaper per pound and available year-round in all parts of the country. But headlines such as the ones above are making consumers wonder whether farm-raised salmon—which is just about all of the salmon you see in supermarkets—is such a great catch after all.
The headlines appeared recently when the Environmental Working Group, a Washington, DC-based not-for-profit environmental research organization, released a report after purchasing farm-raised salmon fillets at supermarkets across the US and testing them for certain contaminants. The group found the fish tainted with chemicals called polychlorinated biphenyls, or PCBs. Widely used in the 1950s and 60s in electrical and heating equipment, paints, plastics, rubbers, dyes, and many other substances, PCBs were banned in 1977 because of concern over their threat to health. The Environmental Protection Agency calls them a “probable human carcinogen.” But they do not break down quickly or easily. An industrial by-product, they linger in water supplies (and air, soil, and food) long after they’re used. According to the Environmental Working Group report, 70 percent of the salmon they looked at “were contaminated with PCBs at levels that raise health concerns.”
The average level of PCBs in the salmon was 27 parts per billion, which actually is well below the Food and Drug Administration limit for seafood of 2,000 parts per billion. But the Environmental Protection Agency has much stricter guidelines, which say that fish containing levels of PCBs between 24 and 48 parts per billion should be limited to 8 ounces a month.
Which guideline is right for you?
The reason the Food and Drug Administration limits are so much more lenient than the limits set by the Environmental Protection Agency is that the FDA monitors commercially sold fish that appears in the supermarket, while the EPA issues its guidelines for recreationally caught fish and subsistence fishing in freshwater lakes and rivers. The assumption is that PCB levels tend to be much higher in fish from “contained” waters where family fishermen fish. Also, it is assumed that people who eat fish they catch for themselves are more likely than others to eat a lot of one specific species rather than a variety of seafoods, and eating fish from a single source increases exposure to any one particular contaminant.
The Environmental Working Group doesn’t buy those arguments, maintaining that the gap between the two sets of guidelines comes from the fact that the FDA isn’t keeping up with current science. The FDA limit was established in 1984, while the EPA threshold was set in 1999.
Admittedly, the FDA itself says it plans on reviewing and updating its guidelines for fish consumption by next year. But before you decide to limit yourself to 8 ounces of salmon a month, consider this. The study from the Environmental Working Group included only 10 salmon fillets—too small a sample to draw definitive conclusions about the average amounts of PCBs in farm-raised fish, according to Charles Santerre, PhD, a food toxicologist and associate professor in the Department of Foods and Nutrition at Purdue University. He also says the study was “biased” because, unlike studies that appear in peer-reviewed scientific journals, independent scientists did not review the findings.
Mark Woodin, PhD, an epidemiologist at Tufts who specializes in occupational hazards, adds that while “farm-raised salmon probably does have higher levels of PCBs than wild” and while those chemicals certainly do present a problem, it’s very difficult to say just how toxic they are. Scientists cannot expose study volunteers to a substance that is suspected of causing harm, he explains, so most studies are limited to workers exposed to PCBs before they were thought to be dangerous. Workers were oftentimes “wearing no protection and sloshing around in the stuff,” he remarks. That diminishes a study’s usability for the public at large. Then, too, because there is so much variation among the people studied—how much they were exposed to and for how long—scientists are left with imprecise data from which it’s hard to draw firm conclusions.
Even if the strict EPA guidelines were known to be the right ones, they are based on the amount of PCBs that are thought to be capable of causing one additional cancer case in 100,000 people over a 70-year lifetime. Compare that, Dr. Woodin says, to “very good, consistent data that show a couple of coldwater fish meals a week can lower your risk of heart disease, which is the biggest killer in developed nations.” Dr. Santerre agrees and, in fact, is concerned that the new report will cause consumers to reduce their fish consumption when it could be so beneficial to their cardiovascular systems.
Alice Lichtenstein, DSc, who heads the Cardiovascular Nutrition Laboratory at Tufts, certainly is still eating fish, including farm-raised salmon, which she says “contains the same amount of omega-3 fatty acids as wild fish.”
Our view: You should be, too. Eight ounces of salmon a month comes to almost three 3-ounce servings, and few people are eating even that much. Indeed, last year Americans averaged only 4.1 pounds each of fillets and steaks from all fish species, salmon included. That comes to an average of only 5 ounces a month—less than the EPA’s red-flag limit.
The American Heart Association’s advice is to eat two fish meals a week. Vary the type of fish, and you shouldn’t be putting yourself in any danger zone.
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