Tuna Fish Dangers:

Mercury in Tuna Fish

By Dr. Ben Kim

Do you eat tuna fish on a regular basis? If so, you should know about a recently published report on dangerous levels of mercury found in canned tuna fish.

The report was published by an environmental group called "Defenders of Wildlife," which contracted New Age/Landmark Laboratory in Benton Harbor, Michigan to test 164 cans of tuna fish that were produced in Ecuador, Mexico, Costa Rica, Thailand, Malaysia, the Philippines, and the United States.

Here are the key points that I took from their report:

  • Cans of tuna fish that were tested to have the highest level of mercury originated from waters around Mexico and Ecuador. Coincidentally, the fishing industry in these areas is known for deliberately casting nets in areas where dolphins are spotted, since large tuna fish are usually found swimming below dolphins.

  • The average mercury content of canned tuna fish that was produced in the United States was generally less than that of imported canned tuna fish.

  • Canned tuna fish that was produced in Asia had the lowest average levels of mercury.

  • Canned tuna fish that was produced in Latin America had the highest average levels of mercury. Some of these cans had levels that exceeded the United States government's limit of 1.0 parts per million.

  • Even canned light tuna was tested as having high levels of mercury. Light tuna is considered by the FDA to be low in mercury compared to other large fish.

  • The two lines of canned tuna that were found to have mercury levels that are higher than the U.S. federal limit are: Sardinar from Costa Rica, which tested at 1.3 parts per million, and Calmex from Mexico, which came in at 1.4 parts per million.

  • Solid pack tuna sold under a brand called "Tuna Real" was found to have levels of mercury as high as 1.5 parts per million.

What does all of this mean for the end consumer? I believe that it is prudent for pregnant women, women who are planning on becoming pregnant, and children to avoid eating more than one can of tuna fish every 2-4 weeks.

Instead of eating tuna, I believe that it is healthier to eat smaller fish such as wild salmon, lake trout, and anchovies. Smaller fish are not as high up on the food chain as larger fish like tuna and shark, and are therefore less likely to bio-accumulate significant amounts of mercury.

What's the problem with steady exposure to mercury through our food choices? Over time, a build up of mercury in our tissues can cause a number of health problems, the most common of which are nervous system damage, cardiovascular challenges, and injury to the kidneys. Most susceptible to these effects are infants and young children.

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