Fish: Life Saver or Killer?
By MARIAN BURROS
From The New York Times
Published: October 18, 2006
A REPORT about the risks and benefits of eating seafood, released yesterday by the Harvard School of Public Health, said consumption of fish reduces the risk of coronary death by 36 percent and total mortality by 17 percent.
A similar report released simultaneously by the Institute of Medicine, part of the National Institutes of Health, was not as optimistic, concluding that there is only enough evidence to say that consumption of fish, especially fatty fish like salmon and mackerel, may reduce the risk of cardiovascular disease.
The Harvard study, to be published in the Journal of the American Medical Association today, said the benefits of eating fish high in omega-3s strongly outweighs risks from contaminants like PCBs and dioxin found in high concentrations in fish like farmed salmon. Calling those risks greatly exaggerated, Dr. Darius Mozaffarian, one of the two authors, said, Seafood is likely the single most important food one can consume for good health.
Dr. Marion Nestle, a professor of nutrition, public health and food safety at New York University, who described the very sunny Harvard study as astonishing, remains unconvinced. The reports conclusion that the risk of death can be reduced by 36 percent is just stunning, she said. It would indeed make eating fish the single most important decision you can make for your health. But those of us who have been in nutrition for a long time have seen miracle foods come and go: vitamin E for heart disease, beta carotene to prevent cancer; now its fish.
Dr. José M. Ordovas, a member of the institutes panel and a professor of nutrition at Tufts, agrees with Dr. Nestle and said the 36 percent figure is based on circumstantial evidence that does not provide definite proof.
Dr. Mozaffarian agreed that, because the evidence is based on observational studies and clinical trial data, it is not definitive, but he added, Its the best evidence we have. As for the studys finding that total mortality could be cut by 17 percent, he said, While one can argue over the precise size of benefits, even if the benefit is only one-half or one-quarter as large, it still greatly outweighs the risk.
The report from the Institute of Medicine tells the government that much more research is needed. Dr. Malden C. Nesheim, chairman of the institutes committee and a provost emeritus at Cornell, said, We are quite cautious because the studies we looked at are not controlled for all the variables, and we cant distinguish between the effects from omega-3s or replacement of other foods in the diet.
The National Oceanic & Atmospheric Administration had requested the institutes report because it said consumers were confused about how much and what kind of fish they should eat. The two studies, which conflict in important aspects, seem unlikely to provide much clarity. The high degree of certainty in one report and the extreme caution in the other, said Rebecca Goldberg, a senior scientist with Environmental Defense, an advocacy group, will make people more confused than ever.
To the surprise of Institute of Medicine officials, NOAA sponsored the hastily called press conference at which the Harvard report was released, even though that study conflicted with the one prepared by the institute. Were just trying to make consumers feel good, said William T. Hogarth, assistant administrator for fisheries of the National Marine Fisheries Service, part of NOAA.
Both reports have come under criticism from environmental groups and from the Consumers Union. In addition to being concerned about the failure of the JAMA and I.O.M. reports to address the risks of mercury in tuna, said the consumer organization, we are also concerned that both reports dismiss concerns about PCBs in most fish.
These reports are urging Americans to eat more seafood as if it were a crisis, Dr. Goldberg said. According to NOAAs own statistics, per capita consumption of seafood has risen from 14.8 pounds in 2001 to 16.6 pounds in 2004.
Jane Houlihan, the research director of the Environmental Working Group, another advocacy group, said, The Harvard study reads like an advertisement for the seafood industry.
Both studies reinforce advice from the Food and Drug Administration and the Environmental Protection Agency in 2004, to eat about six ounces of fish a week, preferably high in omega-3s, with a caveat for women of childbearing age and children under 12 not to eat swordfish, shark, tile fish or king mackerel and to limit their intake of albacore (white meat) tuna to six ounces a week to avoid mercury. For those who eat more fish, both reports advise eating a variety of species to reduce the level of contaminants.
Once again pregnant women are being told its O.K. to eat tuna, Ms. Houlihan said. The reality is, 90 percent of women would exceed governments level for a safe dose of mercury if they ate six ounces of albacore tuna every week as the F.D.A., E.P.A and now I.O.M. recommend.
Dr. Nestle finds the situation so confusing no rational person can possibly figure out how to make sense of it, she said. Fortunately, Environmental Defense and Monterey Bay Aquarium, who specialize in both health and environmental fish issues, provide advisory cards for choosing fish, and no one can manage this without one.
The Environmental Defense list is at oceansalive.org and the Monterey Bay Aquariums is at mbayaq.org/cr/seafoodwatch.asp.