The American council of Science presented its 2006 Top ten of unfounded health scares: tuna takes fourth position.
The Scare: “Mercury in Tuna: New Safety Concerns.†This was the title of the recent Consumer Reports article that sparked the latest scare involving mercury in seafood. Mercury is a toxic metal that is naturally present in the environment and can also be released by human activity such as emissions from coal-burning power plants. When in water, mercury is converted into methyl mercury, a potent neurotoxin, which then enters the food chain. Therefore, methyl mercury is present in small quantities in fish. Larger fish accumulate more methyl mercury than do smaller fish, partly because they are higher up in the food chain.
The Environmental Protection Agency (EPA) sets a “reference dose†for human blood levels of mercury and recommends amounts and types of seafood that women who are or may become pregnant and young children should eat in order to limit their exposure to mercury. Media coverage in 2006 of a few mercury-related reports and recommendations set off new alarm about the effects of mercury found in seafood.
Origin of the Scare: In July 2006, Consumer Reports (33) magazine published an article stating that pregnant women should avoid all canned tuna for fear of the presence of unsafe levels of mercury. Consumer Reports analyzed data from the FDA and concluded that 6% of canned tuna contained levels of mercury higher than what the FDA deems safe levels for pregnant women to consume. Most cans of light tuna contain on average 0.12 parts per million of mercury, while white or albacore tuna has on average about 0.35 parts per million. But 6% of light-tuna cans tested contained levels above 0.12 parts per million, some as high as 0.85 parts per million. (34) Consumer Reports asserted that because the FDA says pregnant women should never eat shark, swordfish, king mackerel, or tilefish, all of which have higher levels of mercury than tuna (king mackerel averages .73 parts per million, for instance), (35) then these new findings should change recommendations for tuna, since the possibility exists that any given can of tuna may have higher than expected levels of mercury.
The article mentioned an increased risk of mercury poisoning in fetuses. The authors claim that studies of fish-eating populations have linked low-level mercury exposure in pregnant women and young children with subtle impairments in neurological and behavioral functioning, such as hearing, eye-hand coordination, and learning ability. While the article admits that the effects of sporadic exposure to the higher mercury levels in some light-tuna cans have not been determined, it continues to say that some scientists are concerned that even brief exposure to those mercury levels at critical points in fetal development may be harmful.
Media Coverage: The coverage included articles from the Chicago Tribune, the Los Angeles Times, and USA Today. The Chicago Tribune (36) headline included “New Warning for Canned Tuna: Mercury Risk for Pregnant Women Too High.†Stories by the Los Angeles Times and USA Today played up the scare and included the benefits of fish consumption as an afterthought. The Pittsburgh Post-Gazette (37) concluded that light tuna had “worrisome amounts†of mercury in it.
In addition, numerous activists groups including the Environmental Working Group (EWG), the Center for Science in the Public Interest (CSPI), and the Mercury Policy Project (MPP), picked up the story. EWG claims to tell consumers “what the FDA won’t†in terms of seafood’s safety. It states that the levels of safe fish consumption recommended by the FDA are too high. CSPI applauded the Consumer Reports “study†and advised pregnant women to limit tuna consumption. MPP also mentioned the new report and suggested that the government should stop subsidizing the seafood industry “at the expense of exposing
The Bottom Line: The Consumer Reports article should be viewed with much skepticism. The FDA says that although some canned tuna may contain higher mercury levels, most are lower. When recommendations are made about the amount of tuna that pregnant women can safely consume, scientists consider the average level of mercury in one serving of tuna. Only 6% of the cans of tuna tested had higher than average mercury levels. “I haven’t seen science that a single serving of a higher level would be of concern,†says David Acheson, chief medical officer of the FDA’s Center for Food Safety and Applied Nutrition. “Mercury is very much a chronic-exposure concern. You build up the levels in the blood, and that seems to be the problem.†(38)
Furthermore, fish is one of the most healthful of dietary selections. It is a good source of protein and omega-3 fatty acids, which are known to be beneficial for our hearts and brains. Several studies have shown that eating more fish, especially fatty fish, is associated with lower rates of heart disease and sudden cardiac death.
A recently published study in the Journal of the American Medical Association (39) confirms that the benefits of moderate fish consumption outweigh any risk from mercury in fish. Researchers from
It was also stated that women who are pregnant, may become pregnant, or are nursing should avoid fish with the highest levels of mercury, including tilefish, swordfish, and king mackerel. Infants of mothers who consumed several portions of other fish weekly showed improved health.
In conclusion, the Consumer Reports article only serves to alarm the public, especially pregnant women or women who may become pregnant. In promoting an unfounded fear of tuna, the most widely consumed fish in
From The American Council On Science