Seafood, wine, rice, vegetables, and other food items associated with mercury biomarkers among seafood and non-seafood consumers: NHANES 2011–2012
Background: Fish/seafood consumption is a recognized source of mercury exposure; other potential dietary sources, particularly among non-seafood consumers, are not as well described.
Objective: To identify foods associated with whole blood total mercury (THg), whole blood methylmercury (MeHg), and urinary mercury (UHg) among seafood and non-seafood consumers.
Methods: This cross-sectional study used National Health and Nutrition Examination Survey (NHANES) 2011-2012 data, a representative sample of the U.S. population. Participants self-reported consuming fish/seafood (N=5427) or not (N=1770) within the past 30 days. UHg was determined from a spot urine sample; this assesses total mercury. Diet was assessed using 24-hour recall. Adjusted regression models predicted mercury biomarker concentrations with recent food consumption while controlling for age, sex, education, and race/ethnicity.
Results: Geometric mean THg was 0.89 µg/L (95% confidence interval (CI): 0.78, 1.02) among seafood consumers and 0.31 µg/L (95% CI: 0.28, 0.34) among non-seafood consumers; MeHg and UHg concentrations follow similar patterns. In adjusted regressions among seafood consumers, significant associations were observed between mercury biomarkers with multiple food categories, including fish/seafood, wine, rice, vegetables/vegetable oil, liquor and beans/nuts/soy. In adjusted models among non-seafood consumers, higher THg was significantly associated with mixed rice dishes, vegetables/vegetable oil, liquor and approached statistical significance with wine (p<0.10); higher MeHg was significantly associated with wine; and higher UHg was significantly associated with mixed rice dishes.
Discussion: Fish/seafood consumption is the strongest dietary predictor of mercury biomarker concentrations; however, consumption of wine, rice, vegetables/vegetable oil, or liquor may also contribute to mercury exposure, especially among non-seafood consumers.