More mercury found in restaurant served tuna/sushi- updated

New research that shows mercury levels are higher in some species of tuna could potentially help consumers minimize their consumption of the silvery metal in their sushi, and thus provide a powerful new tool for regulatory organizations. 

Rutgers University researchers found evidence suggesting that tuna sushi purchased from supermarkets, which tends to be yellowfin tuna, might be healthier than that from restaurants.

They published a study in Biology Letters showing that mercury levels in some species tend to be higher than others, which can be a risk for those who eat tuna frequently at restaurants.  Eateries are not required to declare what species they use in sushi.

Michael Gochfeld, along with his colleagues from Robert Wood Johnson Medical School, analyzed sushi samples from 54 restaurants and 15 supermarkets in New York, New Jersey, and Colorado.

Using a DNA decoding technique, the researchers identified bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), or bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus); they found mercury in all samples.

The mercury levels in all species exceeded or approached the levels permissible by Canada, the E. U., Japan, the U.S. and the World Health Organization.

Bluefin akami- sushi from lean, dark red tuna and all bigeye tuna sushi contained significantly higher levels of mercury than in bluefin toro - sushi from fatty tuna and yellowfin tuna akami.

Canned tuna can also have the same issue.

One study in the Feb 2010 issue of Environmental Toxicology & Chemistry has recently revealed that mercury in tuna is higher than expected.

Researchers at the University of Nevada-Las Vegas found 55% of more than 300 samples of canned tuna from the top three brands in the United States had mercury levels higher than the EPA standard 0.5 parts per million and 5% even higher than 1.0 ppm safety up-limit set by the Food and Drug Administration for commercially sold fish, Healthday.com reported.

Advocate groups have early warned that some brands of tuna are high in mercury and asked the FDA to update its fish consumption advisory which was jointly issued by the FDA and the Environmental Protection Agency.

What does the FDA say about fish consumption?

The current EPA/FDA fish consumption advisory issued in 2004 says that women and young children should not eat shark, swordfish, king mackerel or Tilefish because they contain high levels of mercury.

The advisory also suggests that women and children benefit from eating fish, and should include up to 12 ounces a week of a variety of fish and shellfish that are lower in mercury including the five most commonly eaten types - shrimp, canned light tuna, salmon, Pollock and catfish.

The advisory acknowledges that albacore tuna is higher in mercury than canned light tuna, but also says that "when choosing your two meals of fish and shellfish, you may eat up to 6 ounces of albacore tuna per week.”

David Liu and editing by Rachel Stockton