Seafood ChoiCeS

Seafood Choices: Balancing Benefits and Risks
http://www.nap.edu/catalog/11762.html
ANALYSIS OF ThE BALANCING OF BENEFITS AND RISKS
selenium. Seafood also is a primary source of the omega-3 fatty acids EPA
and DHA. The evidence detailed in Chapter 3 indicates that consumption
of seafood and/or EPA/DHA by pregnant females may provide benefits to
their developing fetuses. Infants receiving EPA/DHA either from breast milk
or supplemented formula may benefit in terms of neurological and visual
development. Similarly, there is evidence that consumption of fish is associated
with cardiovascular benefits in the general population.
These benefits must be balanced against risks to health, as reviewed
in Chapter 4, from exposure to chemical and/or microbial contamination
that may be present in some seafood available to US consumers. The bestcharacterized
risk from chemical contamination of seafood is from methylmercury,
a potent neurotoxin. Thus, the population groups at greatest risk
from exposure to contaminants in seafood are the developing fetus, infants,
and young children. As discussed in Chapter 4, a Reference Dose (RfD) has
been established for methylmercury on the basis of developmental tests in
children born to mothers from populations where seafood is a major part of
their diets. At the same time, evidence suggests the fetus and infant may be
among the principal beneficiaries from certain nutrients in seafood. Evidence
available on levels of MeHg that may be detrimental to nonpregnant adults
has not allowed the formulation of a similar reference dose based on risks
to these population segments.
In establishing their joint advisory targeted at pregnant women and
children, the US Environmental Protection Agency (US EPA) and Food
and Drug Administration (FDA) examined potential intakes of MeHg
that would occur in pregnant women given consumption patterns using
various available commercial sources of seafood. If predatory fish high in
mercury were avoided completely, they concluded that up to 12 ounces of
fish (four 3-ounce servings per week) could be consumed without exceeding
the RfD dose that has been established with studies in populations of
women consuming substantial amounts of seafood (US EPA/FDA, 2004)
(see Chapter 4). Though the committee recognized that the RfD was not
a “bright line” that established a firm cutoff for risk, the FDA/EPA fish
advisory provides reasonable guidelines for pregnant women to consume
seafood in amounts that may confer benefit without significantly increasing
risk. There is little evidence available about levels of methylmercury that
may be detrimental to other segments of the population.
Risks from other contaminants in seafood are, comparatively, less wellcharacterized
than methylmercury. Contamination from persistant organic
pollutants (POPs) has been characterized at exposure levels that result from
industrial releases or occupational exposure, and for fish-consumers in
geographic areas where contaminants are more concentrated. However, at
lower levels of exposure there is less information available on adverse health
effects. In addition, levels of dioxin-like compounds (DLCs) and polychlori-
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