In a new study to be published in January 2011, Consumer Reports warns pregnant women to shun canned tuna amid test results showing concerning levels of mercury in the fish products. The magazine's latest investigation of 42 samples from cans and pouches of tuna bought primarily in the New York metropolitan area revealed that even if women of childbearing age eat less tuna than what the U.S. government recommends, they could exceed safe mercury limits. Consumer Reports also confirmed that white (albacore) tuna usually contains more mercury than light tuna.
"Canned tuna, especially white, tends to be high in mercury, and younger women and children should limit how much they eat. As a precaution, pregnant women should avoid tuna entirely," said Urvashi Rangan, PhD, director of technical policy at Consumers Union, nonprofit publisher of Consumer Reports, in a release.
Although the findings are not entirely groundbreaking—in 2006, Consumer Reports did similar research—Marianne Cufone, director of the fish program for the Washington, D.C.-based nonprofit advocacy group Food and Water Watch, said the study helps keep this "important issue" top of mind for consumers. "I think it's great that groups like Consumer Reports check into these things periodically," Cufone said. "We need watchdog organizations monitoring these issues."
"It's a reminder to consumers to think about choices they're making and how those affect themselves and the planet," she added.
But Consumer Reports is receiving harsh criticism from certain fish lobby groups, such as the National Fisheries Institute, which called the "scare" report "out of step with mainstream science and nutrition advice" on fish consumption.
"Peer-reviewed science shows that pregnant women who limit or avoid seafood may actually be introducing risks from omega-3 deficiency," wrote Gavin Gibbons in a blog on the NFI's website. "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."
The Consumer Reports' findings also come on the heels of a recent study suggesting that the beneficial nutrients in fish outweigh the harmful effects of mercury, which is linked to neurologic, cardiovascular and immune system damage. However, some critics have noted that the researchers of this particular study assume the mercury in subjects' blood cells came from fish when it might be due to other environmental sources, such as coal-fired power plants and dental fillings.
Why stricter guidelines for tuna?
The U.S. Food and Drug Administration and the U.S. Environmental Protection Agency both recommend that women of childbearing age and young children eat no more than 12 ounces a week of light tuna, including 6 ounces of white tuna.
Why then the stricter guidelines from Consumer Reports?
According to the magazine's report, if a woman of childbearing age ate 2.5 ounces (about a half a can) of any white tuna sample tested, she would exceed the daily mercury intake that EPA considers safe. And if that same woman ate 5 ounces (about one can) of light tuna, she would exceed EPA's safe limits.
The Consumer Reports' staff initiated this recent study because the FDA had not responded to the magazine's push to warn consumers about occasional spikes in mercury levels in canned light tuna. Consumer Reports scrutinized the FDA's tests in 2002 and 2004 of mercury levels in hundreds of samples of canned tuna and found that "as much as 6 percent of the FDA's light-tuna samples had at least as much mercury as the average white tuna—in some cases more than twice as much," according to the Consumer Reports' press release.
How retailers and consumers can respond
The effects of mercury overexposure (brain, nervous system and kidney damage) are not worth even the most delectable tuna salad sandwich. For health- and safety-minded individuals, the U.S. mercury standards may be too lax. In fact, the Washington, D.C.-based Environmental Working Group has called these standards "among the worst in the world." The U.S. EPA allows 0.1 of mercury per kilogram body weight per day, but this applies only to recreationally caught fish. The FDA allows 0.4 micrograms of mercury per kilogram body weight per day. By comparison, the World Health Organization recommends only 0.2.
The FDA can pull products from shelves that contain 1 parts per million or more of mercury. According to Consumer Reports, it never has.
The reality is that safer alternatives to tuna are readily available and provide as much or more of beneficial nutrients to pregnant women and others. To help customers choose replacements for tuna, highlight small fish like sardines and anchovies as healthy options.
At Pangaea Naturals, a natural products store in Manahawkin, N.J., store co-owner Mike Greenblatt looks to stock tuna from smaller fish and advises customers to limit large fish consumption to once or twice a week. "Smaller fish will normally have less toxins in general," Greenblatt said. "Also, some of the vendors do have Hg [mercury] content levels printed on the cans."
In addition, retailers can print and offer Food and Water Watch's recently published Smart Seafood Guide to customers. The pocket guide offers safer substitutions for tuna, such as Alaskan salmon, Atlantic mackerel and Pacific halibut.