The first section is an analysis of an educational intervention with the goal of increasing fish consumption among middle-aged, low-income women to decrease risk of sudden cardiac death (SCD). Blood samples from program participants were compared to samples from controls from local health fairs. The intervention was successful as evidenced by a clinically significant increase in blood eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which correlates with lower SCD risk. People who were exposed to health fair messaging also experienced an increase in blood EPA and DHA. The second section is an analysis of data from the National Health and Nutrition Examination Survey (NHANES). Data from the Patient Health Questionnaire Depression Module were analyzed in connection with dietary data on fish and meat consumption and the consumption of their component nutrients, EPA, DHA, and cobalamin (B12). The people who ate the least fish and meat products were most likely to have experienced symptoms indicating major depressive disorder and more likely to report more severe symptoms. Other factors that were associated with depression prevalence and or severity were smoking, poverty, and female sex. The third section is another analysis of NHANES data. The data analyzed were blood lead concentrations in adults and children and correlated dietary, socioeconomic, and lifestyle variables. Blood lead levels in children were positively associated with serum cotinine and African American race and negatively associated with increasing age, later sample collection date, household income, and history of breast feeding. Adult blood lead levels were positively associated with increasing age, African American race, alcohol consumption, serum cotinine, and male sex and negatively associated with income and later sample collection date. Only in African Americans is tap water consumption associated with higher blood lead levels.