Tuna Salad, Light on the Mercury

It's not perfect, but researchers say chunk-light is a better choice.If our oceans weren't contaminated with mercury, canned tuna would be such a healthy food. Now researchers at the University of Nevada, Las Vegas have done the legwork to provide some useful guidelines as to which canned tuna has the least amount of mercury.

After analyzing 155 cans of solid-white, chunk-white and chunk-light tuna from three of the most popular national brands, the team found that chunk light tuna offers the best choice. Its contaminant level averaged 0.28 ppm (parts per million) mercury versus 0.5 ppm in chunk-white tunas. The explantion for the difference is that different canned varieities (albacore, chunk-white, chunk-light, etc) are made from different members of the tuna family tree. As a rule, the larger the fish, the more mercury its flesh will contain due to a phenomemon called biomagnification in which the bigger the fish, the more fish it eats, and the more mercury it is exposed to. Canned chunk-light tuna is made from skipjack, a relatively small member of the tuna family whereas chunk-white tuna is made from albacore, which is a larger fish.

While eating chunk-light tuna is a bit better, it's not perfect. At the 0.5 ppm level of chunk-white tuna, a 55-pound child can safely eat only one serving of white tuna every two weeks according to the researchers. These calculatations suggest the same child could eat the chunk-light tuna about every 10 days. Perhaps the worst news is that 55% of all tuna examined was above the U.S. Environmental Protection Agency's (U.S. EPA) safety level for human consumption (0.5 ppm), and 5% of the tuna exceeded the action level (of 1 ppm) established by the U.S. Food and Drug Administration (U.S. FDA.) As the authors concluded in the study published in the journal Environmental Toxicology and Chemistry, clearly more research and stricter regulation of mercury in canned tuna is desperately needed.

Click here to see the study abstract.