NAS Report On Science Of Seafood's Benefits & Risks

Oct 17: A new report -- Seafood Choices: Balancing Benefits and Risks -- from the National Academy of Sciences (NAS) Institute of Medicine(IOM) says that the fragmented information that consumers receive about the nutritional value and health risks associated with fish and shellfish can result in confusion or misperceptions about this food source. The report reviews the scientific evidence on seafood's benefits and risks and offers examples of how such information might be presented in a more coherent way to the public. It calls for Federal agencies to partner with state, local, and private groups to develop new informational tools and test them with consumers to make sure they work. Malden Nesheim, professor emeritus and provost emeritus, Cornell University, Ithaca, NY and chair of the committee that wrote the report said, "Consumers need better guidance on making seafood choices. The committee's approach to balancing the benefits and risks brings this information together in a coordinated way that applies to all population groups. Our model offers a foundation upon which agencies can develop advice that presents information in a user-friendly way and allows consumers to weigh all the relevant details and make well-informed choices."

The committee found that much of the evidence on seafood's health benefits and risks is preliminary or insufficient. Reliable data on the distribution of some contaminants is lacking, and there is little evidence on how beneficial effects of seafood might counteract some of the risks from contaminants. The committee concluded that, "Evidence suggesting that people who have suffered heart attacks can reduce their risk of future heart attacks by eating seafood is weaker than previously thought. It is also not clear whether consuming seafood might reduce people's risks for diabetes, cancer, Alzheimer's disease, or other ailments."However, the committee confirmed that eating fish and shellfish may reduce people's overall risk for developing heart disease. It is not certain whether this is because substituting the lean protein of seafood for fatty cuts of meat reduces consumers' intake of saturated fat and cholesterol or because of the protective effects of omega-3 fatty acids, which are found in relatively high amounts in many fish species. The report also found evidence that maternal consumption of omega-3 fatty acids through seafood can contribute to vision and cognitive development in infants and lengthen the duration of gestation.

The report indicates that seafood is the major source of human exposure to methylmercury, a contaminant that accumulates in the muscle of animals over time. Because evidence suggests that methylmercury can disrupt neurodevelopment in the fetus, the report supports current recommendations that women who are pregnant or wish to become pregnant avoid consumption of lean, predatory fish such as swordfish, shark, king mackerel, and tilefish, and limit their consumption of albacore, or "white," tuna. Other potential risks associated with seafood are exposure to persistent organic pollutants such as dioxin and PCBs -- though there is not clear evidence on the adverse effects associated with these compounds -- and microbial infections, which are contracted mainly through the consumption of raw or undercooked fish and shellfish.

The committee presented a variety of tools that could be used to inform consumers, including a series of questions designed to provide advice tailored to their specific needs. This way of arriving at a decision should be used as a basis for developing additional decision-support tools and other consumer guidance, the report says. The committee also developed sample graphs illustrating how levels of omega-3 fatty acids and methylmercury vary in different types of fish. These graphics may present this information to consumers more effectively than plain text or numbers, but their design and wording have not been tested among consumers.

The Mercury Policy Project (MPP) and other advocates wrote a letter expressing concerns over the selection of a consumer representative who had close ties with food producing companies and the process NAS used in selecting committee members. In their letter the groups complained that by selecting committee member, Jennifer Hillard of the Consumer Alliance of Canada, "the IOM has chosen someone whose past record suggests close ties with food producing companies as well as a wide range of industry trade groups."

Access a NAS news release (click here). Access the complete report (click here). Access a report summary (click here). Access Sample Consumer Guidance (click here). Access a recording of the news conference (click here). Access the MPP letter (click here). Access the MPP website for additional information (click here). [*Toxics]