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Post-Doctoral Fellowships
Assessment of Dietary Exposure to Methylmercury and
Polyunsaturated Fatty Acids through Fish Consumption and
the Association with Cardiovascular Health
Fish are a source of high-quality protein, contain low levels of cholesterol and are one of few
sources of polyunsaturated fatty acids (Omega-3) needed for neurodevelopmental, cardiovascular
(CVD) and cognitive health. However, fish consumption may also increase the risk of exposure to a
range of environmental toxins. Understanding and communicating the benefits and risks associated
with eating fish is challenging and there is considerable confusion among the general public. In
part, this is because most health advice targets women of childbearing age and young children
with reference to the risks posed by methylmercury (MeHg) exposure for neurodevelopment.
Dissemination of information on other health outcomes, environmental risks and nutritional
benefits is much more limited.
The purpose of this research was to improve our understanding of the risks and benefits of
fish consumption for cardiovascular health with reference to MeHg exposure and Omega-3
intake. NHANES data on US fish consumption, broken down by species was combined with US
Department of Agriculture data on Omega-3 uptake and MeHg residues in fish tissue.The resulting
exposure profile was used as a hypothetical dose and interpolated into dose-response functions
from the literature using three different consumption scenarios: the national status quo based on
the data; increasing consumption to 16oz per week in accordance with health recommendations
(but without changing species mix); and changing species consumed.
Preliminary findings included: (1) the main source of MeHg exposure is tuna; (2) increasing fish
consumption, without changing the mix of species leads to a proportionally larger rise in MeHg
exposure than to Omega-3 uptake; (3) relatively small changes in the mix of species consumed, in
particular lowering tuna and increasing shrimp and salmon consumption, improve the risk profile
and do not entail significant additional cost; (4) a 15% reduction in MeHg exposure leads to an
annual reduction of 151 CVD-related deaths.
The modeling platform developed in this research is currently being used as the basis for an Israeli
case study. The platform has also been modified for use in a study of dietary pesticide uptake in a
sample of Israeli children.
Fellow
Shirra Freeman
Harvard University, USA
Supervisor
James K. Hammitt
2009-2010