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Are Fish Oil Supplements Safer Than Eating Fish?

October 2005

By Debra Fulghum Bruce, PhD

Ensuring the Safety of Fish Oil Supplements

While there is no guarantee that the fish you eat is free of contaminants, the tide has turned when it comes to guaranteeing the safety of omega-3 fish oil supplements. In fact, recent studies substantiate that some supplements are safer than eating fish. For example, analyzing five brands of fish oil supplements, researchers from Brigham and Women’s Hospital and Harvard Medical School in Boston found that levels of PCBs and organochlorine pesticides were below the detectable limit in all five brands tested. The study authors concluded that if a person were to eat fish from the Great Lakes at the optimal recommended amount of about 400 grams per week, he would consume at least 70 times more PCBs and 120 times more organochlorine pesticides than if he were to supplement with the average daily dose of fish oil (1.5 grams) for one week.24

With growing concerns about contamination and recent journal studies warning of the health effects of mercury and PCBs from marine sources, health-conscious consumers are demanding more information about the safety of the fish oil products they consume. Reputable fish oil products now undergo rigorous testing for purity and concentration by independent quality-assurance programs such as the International Fish Oil Standards (IFOS) program. Under the direction of Canada’s Nutrasource Diagnostics Inc., a world leader in omega-3 diagnostic testing and product analysis, the IFOS program measures the quality of omega-3 products in the context of global standards developed by the WHO and the Council for Responsible Nutrition (CRN), a trade association for supplement suppliers and manufacturers. Oddly, FDA standards for allowable contaminants in fish oil are the least stringent of all of these organizations.

When a third-party laboratory performs an assay of fish oil products to determine whether the active agents meet the label claim, the technicians review the presence of contaminants in the product and check the rate of dissolution (how fast the product releases within a specific time), among other tests for purity and quality.

In testing for PCB, dioxin, and furan levels, the IFOS testing service uses the highly specialized technique of gas chromatography mass spectrometry.25 The fish oil’s omega-3 content is also tested as a percentage of weight using advanced gas chromatography techniques.26

The IFOS service tests mercury using cold water vapor atomic absorption spectroscopy. Heavy metals such as arsenic, nickel, cadmium, and lead are analyzed by microwave-assisted digestion in nitric acid.

After submitting fish oil to the most rigorous assay laboratory, the IFOS program compares the product to far more stringent standards than those established by the WHO or CRN. Testing fish oil at these far lower levels of detection affords consumers a much greater margin of safety. For example, the Council for Responsible Nutrition Voluntary Monograph allows a maximum mercury content in fish oil supplements of one-tenth of one (0.10) parts per million. The IFOS program tests the product at a far greater detection limit of 10 parts per billion to demonstrate to consumers a premium level of product purity and safety. While the CRN Voluntary Monograph allows a maximum PCB content of 0.09 of one part per million, the IFOS program tests product levels at an even greater detection limit in parts per trillion to provide for a much greater margin of safety.

Life Extension Products Attain Highest Rating

Life Extension’s fish oil supplements exceed the IFOS’s testing assay for EPA and DHA potency and purity, earning the highest possible rating, signifying an “exceptional product batch.”

Ratings are based on the CRN Voluntary Monograph standard or the WHO standard in each of the four categories shown below.

  • Category 1: Omega-3 Concentration tests the product’s omega-3 levels and compares the results to the label claim on a per-gram basis.
  • Category 2: Contaminants tests for mercury, PCBs, dioxins, and furans, and lists the totals for each testing type with the detection limit used and the product’s contaminant compliance.
  • Category 3: Oxidation tests peroxide and total oxidation to assess the product’s stability.
  • Category 4: Heavy Metals tests for arsenic, cadmium, nickel and lead.

The IFOS report states that levels of PCBs, PCDDs (poly-chlorinated dibenzo-dioxins), and PCDFs (polychlorinated dibenzo-furans) in Life Extension’s fish oil supplements were well below the maximum allowed by the CRN and WHO. Moreover, Life Extension’s fish oil had no mercury, arsenic, lead, nickel, or cadmium content evident, and was under the CRN’s maximum allowable score for peroxide and oxidation, demonstrating the highest premium level of purity and safety.


Today, high levels of contaminants such as mercury, PCBs, and dioxins in our environment and waters make eating certain fish regularly a potentially risky dietary choice. This does not mean that fish meals should be avoided. Published studies clearly show health benefits for those who eat fish. The problem is that some people are overdoing it and eating too much of the wrong kinds of fish. Fortunately, the wealth of health benefits associated with fish consumption can be safely and readily obtained from premium fish oil supplements. Rigorous testing standards and unparalleled attention to quality help create safe, effective fish oil products for you and your family.


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