Fish Oil May Contain Flame Retardants

Flame retardants have been showing up in some surprising places, from human breast milk to peregrine falcon eggs. Now this growing list can be expanded to include dietary supplements based on cod liver oil, according to a new study.

European scientists have found that flame retardant levels have increased significantly during the past four years in products containing cod liver oil, a common component of dietary supplements.

Fish and vegetable oils are in high demand as dietary supplements because they contain omega 3 fatty acids, which have been linked to various health benefits, including reduced risk of heart disease.

In recent years, however, scientists have shown that fish oils are prone to contamination by organic chemicals. For example, researchers have found that farm-raised salmon contain more contaminants than wild salmon, which they attribute partly to the fish oils used to supplement salmon feed.

"We analyzed 21 commercially available fish and vegetable oil dietary supplements for selected contaminants," says Miriam Jacobs, Ph.D., who lectures in food safety and toxicology at the University of Surrey in Guildford, U.K, and was one of the authors of the latest study involving cod liver oil. The supplements, purchased from retailers in the U.K., contained four classes of oils: pure vegetable oils, fish and vegetable oil formulations, cod liver oil and whole body fish oil.

Jacobs and her coworkers measured levels of persistent organic pollutants in the supplements, including pesticides, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), which are used widely as flame retardants. They then compared the values with levels measured in the same brands purchased eight years ago from the same retailers, and with fish oils used to supplement salmon aquaculture feeds obtained four years ago. In earlier work, Jacobs had found a relationship between pollutants in these feeds and in farmed European salmon.

Supplements based on vegetable oil and whole body fish oil showed little or no contamination throughout the current and previous studies. "The cod liver oils have similar levels of PCBs and pesticides compared to samples obtained from the same outlets," Jacobs says. "But the levels of flame retardants are higher."

Flame retardant levels in cod liver oils from the new study ranged from about 15-34 nanograms per gram of fat, while the range was 0-13 only four years ago. "This is a relatively large increase," Jacobs says. "The extensive use of these chemicals in recent years means that they can get into places where they shouldn't be, such as the marine environment."

The findings add to a growing number of studies that have found flame retardants in unexpected places, from human breast milk in the United States to peregrine falcon eggs in Sweden.

For more information on flame retardants

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