Dufault et al. 2015 — Blood inorganic mercury associated with fasting glucose in NHANES
Analysis of NHANES data (n=16,232) found a statistically significant direct association between blood inorganic mercury and fasting glucose levels (p<0.001), providing epidemiological support for the hypothesis that dietary exposure to inorganic mercury from heavily processed foods, including high-fructose corn syrup (HFCS) manufactured with mercury-cell chlor-alkali processes, contributes to glucose dysregulation. The authors also conducted a small community-based intervention (n=10 American Indian college students) comparing a macroepigenetics nutrition course against a corn-sweetener elimination support group, finding that participants in the nutrition course showed improvements in fasting glucose and lower blood inorganic mercury trends.
Key numbers
- NHANES analysis: n=16,232; blood inorganic mercury directly associated with fasting glucose, p<0.001.
- Community intervention: n=10 American Indian college students randomly assigned to two groups over 10 weeks.
- Nutrition course group: significant improvement in diet quality (p<0.01) and fasting blood glucose (p<0.01); lower blood inorganic mercury trend (p=0.052).
- Corn-sweetener elimination group: significant weight loss (p<0.01) and reduced BMI (p<0.01).
- Mercury speciation performed by EPA methods at Duquesne University (H.M. Kingston et al.); total and inorganic mercury distinguished in blood.
- Hypothesized source: inorganic Hg contamination of HFCS from mercury-cell chlor-alkali chlorine used in corn starch manufacturing; vegetable oils manufactured by alkali refining; flour bleached with mercury-cell chlorine.
Methods (brief)
NHANES dataset secondary analysis using a published statistical method to evaluate blood inorganic Hg vs. fasting glucose. Mercury speciation via EPA methods (Duquesne University group). Community intervention: pre/post dietary assessment, fasting glucose and insulin, blood mercury, weight, and BMI over 10 weeks. Evidence tier is B rather than A due to the non-primary-occurrence-data nature of the dietary mercury hypothesis, the small community intervention n, and publication in a lower-tier journal (Integrative Molecular Medicine); the NHANES association is the load-bearing finding.
Implications
Certification: Provides population-level epidemiological signal linking blood inorganic mercury to glucose outcomes. The proposed pathway (HFCS and processed food as inorganic Hg sources) is plausible given known mercury use in chlor-alkali manufacturing but is not fully established. HMT&C assessments of products containing HFCS or refined vegetable oils should note this pathway as a potential inorganic Hg exposure route.
Courses: Illustrates that inorganic mercury can enter food via industrial processing rather than environmental contamination alone; mercury speciation in blood distinguishes inorganic from methylmercury and has different dietary source implications.
App: Processed foods with HFCS from mercury-cell manufacturing should be noted as a potential inorganic Hg exposure route, though the magnitude of exposure from this source is uncertain and contested.