200 Years. 200 Stories. Story 194: “A Fishy Supplement ”

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environmental chemist Linda Zaoudeh
Environmental chemist Linda Zaoudeh holds a fish oil supplement.

A Fishy Supplement

In 2006, Academy Research Associate and Philadelphia University chemistry professor Dr. Jeff Ashley shed new light on the contents of over-the-counter fish oils, revealing that the capsules contain more than just omega-3 fatty acids. Ashley tested samples of the popular nutritional supplements and found that they contained levels of polychlorinated biphenyls (PCBs), a “legacy” contaminant that was banned in the U.S. in the 1970s. When Ashley later looked at some of the fortified vitamins and food that his young son was eating and noticed that they also contained fish oils, he wanted to find out whether PCB levels were similarly high in products marketed towards children.

Using the facilities and resources of the Academy’s Patrick Center for Environmental Research and enlisting the help of former student Josh Ward and Patrick Center scientists Mike Schafer and Linda Zaoudeh, Ashley and his team tested 13 popular over-the-counter children’s fish oil supplements. They found that PCB concentrations were low compared to adult fish oil supplements, so while children are exposed to PCBs from fish oil supplements, the exposure occurs at very low levels. In fact, notes Ashley, children are exposed to more PCBs from eating fresh or frozen fish, making fish oil products a potentially safer way to get essential fatty acids (though it is important to remember that fresh fish contains other valuable nutrients).

Ashley emphasizes that these findings are not a reason to stop taking fish oil pills altogether as the benefits may far outweigh the risks of low-level PCB contaminants, he does caution that it is a good idea to be wary about fish oil pills for kids since they are still developing mentally and physically. He also suggests choosing fish oil products from small species such as anchovies and sardines that are lower in the food chain, since top predators such as cod and shark tend to accumulate contaminants to a higher degree.

Learn more about the pioneering research made possible by the state-of-the art instrumentation, equipment, and resources of the Patrick Center.

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