There are some articles appearing just now about a lawsuit claiming some big chains are selling PCB contaminated fish oil. This is interesting. Years ago I strongly urged patients to make sure that any fish oil they purchased had been tested for purity.
My rationale was concern over mercury, PCBs and other toxins. As we had evidence of growing mercury levels in people, particularly in San Francisco and New York City with both dioxins and PCBs were showing up in farm raised salmon, this seemed to be a likely problem. Then a couple of reliable independent labs (most notably ConsumerLabs.com in 2008) tested almost 70 different fish oils sold in stores and published the results.
What did they find? They found that none of the oils, including some sold by companies accused in this current lawsuit, had detectable levels of any toxins. They did find that a few did not have as much omega-3 oils as they claimed or that the capsules fell apart too easily.
There were a couple of reasons why my expectations were wrong. First, although farm-raised salmon had shown evidence of contamination, salmon was not being used for oils. Second, mercury is not very fat soluble and so is not concentrated in oil.
What is up now? Is something different? Are the fish different? As salmon oil has become a popular form of fish oil maybe my old concerns are becoming reality? Are the same fish being used (typically sardines, anchovies and mackerel) but now more laden with toxins? Was there something odd about the testing, either now or then? If it has to do with the testing, it would most likely be an issue with the current batch as the prior testing was performed by two different labs not a single lab as now.
We will all have to stay tuned to learn the answers.
Best
Michael Carlston, MD