Younger women and children should limit the amount of tuna they eat and pregnant women should not eat tuna at all, because of mercury levels found in the canned and packaged fish, says new report in the January 2011 issue of Consumer Reports.
Albacore or white tuna usually contains far more mercury than light tuna, according to Consumer Reports , and canned tuna is the most common source of mercury in our diet.
In order to test current levels, investigators for the periodical tested 42 samples from cans and pouches of tuna bought mostly in the New York City area. They found all the samples contained measurable levels of mercury, ranging from 0.018 to 0.774 parts per million. Samples of white tuna had 0.217 to 0.774 ppm of mercury and averaged 0.427 ppm. According to Consumer Reports, if a woman of childbearing age ate about half a can of any of the tested samples, she would exceed the daily mercury intake the Environmental Protection Agency considers safe.
The Food and Drug Administration and the EPA guidelines indicate women of childbearing age and young children may eat up to 12 ounces a week of light tuna or other "low in mercury" seafood, including, within that limit, up to 6 ounces per week of white tuna. But Consumer Reports believes that may be too much. Because mercury can cause defects to the nervous system during fetal development, Consumers Union, the nonprofit publisher of Consumer Reports, advises pregnant women, as a precaution, to avoid eating tuna. It also advises that children who weigh more than 45 pounds limit their intake to 12.5 ounces of light tuna or 4 ounces of white tuna per week, and children who weigh less than 45 pounds consume no more than 4 ounces of light tuna or 1.5 ounces of white tuna.
Some critics, including fish producers, say Consumer Reports is overblowing the research.
"Consumer Reports' suggestion that pregnant women limit the amount of fish they eat, outside of the FDA's four fish to avoid, is reckless and has the potential to harm public health," says the National Fisheries Institute in a statement "Peer-reviewed science shows that pregnant women who limit or avoid seafood may actually be introducing risks from omega-3 deficiency. Advising pregnant women to cut canned tuna out of their diet and for others to limit their consumption based merely on a magazine's editorial opinion is irresponsible."
But Consumer Reports is asking for change. Due to the results of the investigation, the publication's editors are asking the FDA strengthen its current guidance and advise pregnant women to avoid tuna altogether. The group also believes the FDA should continue to test for mercury in seafood across the country, and provide U.S. consumers updated information on mercury levels in fish, as well as diet alternatives
"Fortunately, it's easy to choose lower-mercury fish that are also rich in healthful omega-3 fatty acids," says Dr. Urvashi Rangan, director of Technical Policy, at Consumers Union. "That's especially important for women who are pregnant or might become pregnant, nursing mothers, and young children, because fetuses and youngsters are still developing their nervous systems and are therefore at particular risk from methylmercury's neurotoxic effects."
Lower mercury seafood includes shrimp, crab and cod.