[PERSPECTIVE]

by Michael T. Morrissey

Mercury in Seafood: Facts and Discrepancies

disparity exists between there are low-level toxic effects in seafood that it would be health-care professionals. what we read in the popular from MeHg in seafood. detrimental to human health to Articles such as “Mercury in A press and what research- The Environmental Protec- reduce consumption levels. Tuna” in the July 2006 issue of ers are discovering about the tion Agency (EPA) used the Unfortunately, the message Consumer Reports cause further value of eating seafood. Faroe data as the basis for about health benefits from confusion among consumers. Confusion stems mainly its reference doses for MeHg eating seafood was lost in the The article claimed that their from two questions: “What exposure, taking the position 2004 EPA/Food and Drug Admin- (anonymous) “fish-safety levels of methylmercury that a reference dose cannot istration advisory for women of experts” found that even (MeHg) exposure may cause be determined from a study child-bearing age (www.cfsan. light tuna might prove risky to demonstrable harmful effects for (Seychelles) where the data fda.gov/~dms/admehg3b.html). pregnant women and the fetus. humans, especially the fetus?” showed no adverse effects. Americans are risk-adverse in They called on pregnant women and “When do potential risks Recent work shows that their food habits, and the media to “avoid canned tuna entirely,” of MeHg in seafood outweigh the benefits from seafood focused on hypothetical risks needlessly scaring women away the well-documented benefits consumption greatly outweigh and the warnings in the advisory, from one of the best sources of seafood consumption?” the risks. Numerous scientific such as avoiding certain spe- of health-promoting LC-PUFAs Two major epidemiological publications have reported cies of fish (shark, swordfish, in the diet. This type of non- studies followed more than diverse health benefits of tilefish, and King mackerel). scientific analysis and advice, 500 families in the Faroe and Seychelles Islands over an Nonscientific analysis and advice … only enhances fear and mistrust among consumers…. extended period. They measured maternal MeHg levels and consuming fish regularly from The advisory urges women while generating headlines, conducted extensive cognitive early childhood through old age. of child-bearing age to eat 12 only enhances fear and mistrust testing on the offspring. The In contrast, there is no evidence oz of a variety of low-MeHg among consumers and does a Faroe study showed some that Americans are harmed by fish/week because of the health disservice to society as a whole. negative effects of MeHg, the small amount of seafood they benefits. Because canned The National Academy of while the Seychelles study consume. While the positive link albacore (white) tuna has higher Sciences will soon issue its found no detrimental effects. between seafood consumption levels of MeHg than canned expert-panel review on seafood Critics of the Faroe study and reduction of coronary heart light tuna, the advisory recom- consumption and its risks and point out that the main source disease is well known, the role mends consuming only 6 oz of benefits. In the meantime, I take of MeHg is pilot whale meat and of seafood and its long-chain albacore/week, but up to 12 oz heart in the words of Susan blubber, which contains high lev- omega-3 polyunsaturated of light tuna/week. Considering Carlson of the University of Kan- els of MeHg and organochlorides fatty acids (LC-PUFAs) in that Americans are currently sas Medical Center, who, when and only low levels of selenium, improving cognitive function eating only 5 oz of fish/week, recently asked at a forum on which counters the toxic in infants and mental health the advisory is actually recom- seafood consumption what she effects of MeHg, whereas in the in the general population is mending that this targeted group would recommend to her preg- Seychelles, people consume 12 becoming more evident. of consumers more than double nant daughter, said, “I would servings of fish/week and do A series of papers in the their seafood consumption. tell her to follow the EPA/FDA not eat whale or sea mammals. November 2005 issue of the However, the advisory may Advisory and be sure to eat a Critics of the Seychelles study American Journal of Preventive be having the opposite effect. variety of fish twice a week, and say that the cognitive endpoints Medicine compared the conse- After FDA issued a similar advi- enjoy a healthy pregnancy.” FT tested (more than 40 globally quences of reducing seafood sory in 2001, one study showed accepted tests) were not sensi- consumption with the perceived a 17% decrease in seafood Michael T. Morrissey, a Fellow and Professional tive enough to pick up nuances benefits of avoiding hypothetical consumption among pregnant Member of IFT, is Professor and Director, Seafood Laboratory, Oregon State University, of MeHg toxicity. Therefore, risks and found that there are women. The wrong message Astoria ([email protected]). the jury is still out on whether so many beneficial compounds was getting out, even among pg 132 08.06 • www.ift.org