Elevated blood Hg at recommended seafood consumption rates in adult seafood consumers.
Level 4 - case-series / case-control
Cross-sectional observational exposure study without a control group
PubMed 24780236 · doi:10.1016/j.ijheh.2014.03.007
What was done
Researchers measured blood total mercury concentrations and dietary seafood intake in 285 adult avid seafood consumers in Long Island, New York, who met eligibility screening for predicted blood mercury exceeding the US EPA reference concentration (5.8 ug/L). Relationships between blood mercury levels and specific seafood types and consumption frequencies were analyzed using multiple linear regression.
What was found
Seafood consumption in the study population averaged 14.4 kg/year, which was over 2 times the US average of 6.8 kg/year. Mean blood mercury was 4.4 times the national average, and 42% of participants exceeded the 5.8 ug/L safety threshold. Elevated mercury occurred across all consumption rates, including the recommended 2 meals per week. Significant positive associations with blood mercury (in ug/L) were observed for weekly tuna steak or sushi consumption (beta = 6.30), monthly swordfish, shark, or marlin consumption (beta = 2.54), and weekly swordfish, shark, or marlin consumption (beta = 9.47).
Why it matters
These findings show that following standard dietary recommendations for seafood frequency can still result in elevated mercury exposure if large predatory species are selected. It highlights the need for public health guidance to emphasize specific fish species rather than overall seafood intake alone.
Limits
The study is cross-sectional and relies on self-reported dietary frequency, introducing potential recall bias. The sample was selectively recruited from avid seafood consumers in a single geographic area, limiting generalizability to the broader population. Clinical health outcomes and concurrent protective nutrients were not assessed.
Cited by
- supports Frequent tuna consumption can lead to elevated blood mercury levels.