Academic journal article Environmental Health Perspectives

Quantitative Approach for Incorporating Methylmercury Risks and Omega-3 Fatty Acid Benefits in Developing Species-Specific Fish Consumption Advice

Academic journal article Environmental Health Perspectives

Quantitative Approach for Incorporating Methylmercury Risks and Omega-3 Fatty Acid Benefits in Developing Species-Specific Fish Consumption Advice

Article excerpt

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.

OBJECTIVES: Our 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.

METHODS: We 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.

CONCLUSIONS: 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.

KEY WORDS: cardiovascular risk, fish advisory, methylmercury, neurodevelopment, omega-3 fatty acids, risk/benefit. Environ Health Perspect 117:267-275 (2009). doi:10.1289/ehp.11368 available via http://dx.doi.org/ [Online 3 September 2008]

**********

A decade ago, the landmark studies from the Seychelles (Davidson et al. 1998) and Faroe islands (Grandjean et al. 1997) were unfolding and a debate was raging over how much risk is associated with methylmercury (MeHg) in fish. Both the Seychelles and Faroe studies involved populations that have a high per capita consumption of fish and MeHg body burdens generally higher than in the United States (Davidson et al. 1998; Grandjean et al. 1997). The Seychelles study showed no evidence of harm, whereas the Faroe study, at similar MeHg exposure levels, showed significant neurodevelopmental deficits at birth and into the early school years (Axelrad et al. 2007). Interpretation of these studies by the U.S. Environmental Protection Agency (EPA) and Agency for Toxic Substances and Disease Registry (ATSDR) differed, creating confusion in federal and state government over how to set fish consumption advice (ATSDR 1999; U.S. EPA 2001). A National Academy of Sciences report [National Research Council (NRC) 2000] helped resolve the debate by concluding that MeHg in fish is an important public health risk and developed a dose-response analysis for neurodevelopmental effects that was subsequently used by the U.S. EPA to derive the reference dose (RfD) (U.S. EPA 2001). The Seychelles study, although still overall a negative (without effects) study, recently found some evidence suggestive of a latent MeHg effect (Davidson et al. 2006). An ongoing study of a birth cohort in Massachussetts shows an association of MeHg exposure with neurodevelopmental effects at lower levels of exposure than in prior studies (Oken et al. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.