Positive Health Online

Abstract

GINSBERG and TOAL, Connecticut Department of Public Health, Hartford, Connecticut 06134, USA. gary.ginsberg@po.state.ct.us  developed a method to quantitatively analyze the net risk/benefit of individual fish species based on their methylmercury (MeHg) and omega-3 FA content.

Background

Despite general agreement about the toxicity of methylmercury (MeHg), fish consumption advice remains controversial. Concerns have been raised that negative messages will steer people away from fish and omega-3 fatty acid (FA) benefits. One approach is to provide advice for individual species that highlights beneficial fish while cautioning against riskier fish. The authors' goal in this study was to develop a method to quantitatively analyze the net risk/benefit of individual fish species based on their MeHg and omega-3 FA content.

Methodology

The authors identified dose-response relationships for MeHg and omega-3 FA effects on coronary heart disease (CHD) and neurodevelopment. We used the MeHg and omega-3 FA content of 16 commonly consumed species to calculate the net risk/benefit for each species.

Results

Estimated omega-3 FA benefits outweigh MeHg risks for some species (e.g., farmed salmon, herring, trout); however, the opposite was true for others (swordfish, shark). Other species were associated with a small net benefit (e.g., flounder, canned light tuna) or a small net risk (e.g., canned white tuna, halibut). These results were used to place fish into one of four meal frequency categories, with the advice tentative because of limitations in the underlying dose-response information. Separate advice appears warranted for the neurodevelopmental risk group versus the cardiovascular risk group because we found a greater net benefit from fish consumption for the cardiovascular risk group.

Conclusion

This research illustrates a framework for risk/benefit analysis that can be used to develop categories of consumption advice ranging from 'do not eat' to 'unlimited', with the caveat that unlimited may need to be tempered for certain fish (e.g., farm-raised salmon) because of other contaminants and end points (e.g., cancer risk). Uncertainties exist in the underlying dose-response relationships, pointing in particular to the need for more research on the adverse effects of MeHg on cardiovascular end points.

References

Ginsberg GL and Toal BF. Quantitative approach for incorporating methylmercury risks and omega-3 fatty acid benefits in developing species-specific fish consumption advice. NLM. PMC2649230. Environmental Health Perspectives. 117(2): 267-75. Feb 2009.