Mercury levels found to be higher in restaurant sushi tuna than supermarket

An innovative and alarming study was just published in the journal Biology Letters that not only confirms the high level of toxicity of certain tuna species and uses DNA 'barcode' technology to reveal that the type of tuna in most restaurant sushi is the most contaminated with mercury.The authors remind us:

"Excessive ingestion of mercury—a health hazard associated with consuming predatory fishes—damages neurological, sensory-motor and cardiovascular functioning."

It can be difficult to identify a specific tuna species and know where it came from using conventional methods. This is where DNA barcodes advances the science:

"Accurate identification of commercial fish species has many public health and legal applications. DNA barcodes—short nucleotide sequences used to identify species—can serve as an important tool allowing regulatory agencies to recognize ambiguous food items that are fraudulent or hazardous."

The authors undertook an extensive study to match confirmed identity with mercury content:

"We tested the mercury content of 100 tuna sushi samples from 54 restaurants and 15 supermarkets collected from October 2007 to December 2009 in New York, New Jersey, and Colorado."

What did they find?

"The mean mercury concentrations of all samples exceed the concentration permitted by Japan, and the maximum daily consumption considered safe by the US Environmental Protection Agency. Mean mercury levels for bluefin akami exceed those permitted by the US Food and Drug Administration, Health Canada and the European Commission.On average, one order of Bigeye Tuna sushi—the species used most often for sushi—exceeds the safe maximum daily dose recommended by Health Canada and the safe limit established by the World Health Organization and FAO for women of childbearing age."

Moreover...

"Because the mercury concentrations found in our sushi were significantly higher than levels documented by the Food and Drug Administration this could reflect that our samples came from larger fish (the FDA lacks bluefin data). We found significantly lower mercury levels in supermarket sushi because samples were dominated by Yellowfin Tuna, which comprised a minority of restaurant samples and was found to be the species with the lowest mercury concentration."

At this time health agencies are  not using these findings that place Bigeye and bluefin tuna in the category that the FDA and EPA advise should be totally avoided by pregnant or nursing women and children. You may also like to read a report on this study published in Science Now by the American Academy of Sciences. How do you find out if mercury is a problem for you? Not by provoked chelation (see the earlier post), and inquire about or 'stay tuned' for posts on porphyrin profiles, anti-mercury antibodies and MELISA test technology.