The Truth Behind Fish Oil Concerns

March 3, 2010 — -- Fish oil supplements are constantly touted for their seemingly miraculous health benefits because they contain omega-3 fatty acids. But a new lawsuit contended that they may contain something else, too: PCBs, industrial chemicals that were banned in the 1970s because they caused cancer and birth defects.

Environmental activists who tested 10 different fish oil supplements say each contained PCBs.

Click here to read "Good Morning America's" full report.

Click here to read the manufacturers' response to the lawsuit.

While people should always be concerned with exposure to toxins, the charges still need to be verified, ABC News' senior health and medical editor Dr. Richard Besser said. He explained that only one sample of each product was tested and more testing is needed to truly determine potential exposure.

It should also be noted that requirement for product labeling in California is very conservative and the World Health Organization considers these levels of exposure to be safe, Besser said.

Consumers should not necessarily avoid the fish oil supplements because of PCB concerns, Besser said. But weighing the risk really comes down to how beneficial fish oil supplements are to the consumer, he said.

For people with heart disease, omega-3 acids can greatly reduce the risk of heart attack or dying from heart failure, Besser said, adding that he would not advise heart patients to stop taking fish oil supplements based on the known information.

But if someone has a low risk of heart disease and is concerned, then he or she could stop taking the supplements until further testing is done, Besser said. Instead, he suggested, follow the guidelines from the American Heart Association to find other sources of omega-3 acids such as fatty fish.

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