Balancing nutritional benefits, contaminant concerns and environmental sustainability in the seafood debate

Seafood contains healthy omega-3 fatty acids, but often contains dangerous chemical contaminants, most commonly methyl mercury, which binds to muscle proteins, and persistent organic pollutants (POPs), which accumulate in fat. Fatty fish, such as farmed salmon, contain high levels of both omega-3 fatty acids and POPs but little methyl mercury, while other less fatty fish, such as tuna, contain high levels of methyl mercury, but not extraordinarily high levels of POPs. Other popular fish, such as Chilean sea bass, are not known to be particularly contaminated, but are slow growing and in danger of being depleted because of overfishing. The public receives conflicting information on the risks vs. the benefits of consumption of fish. There is no consensus on the degree of benefit derived from consumption of omega-3 fatty acids, nor the degree of risk of cancer, neurobehavioral abnormalities and other diseases caused by ingestion of the contaminants. Recent meta-analyses have attempted to address the risks vs. benefits, but have reached conflicting conclusions. There is an urgent need for a systematic analysis of levels of omega-3 fatty acids and contaminants, both methyl mercury and POPs, in all those species of fish that are commercially available, and development of consumption advisories that are objective, based on hard scientific evidence with attention to sustainability of fisheries. This information has important ramifications for both global seafood supplies and human nutrition.