Collections > Electronic Theses and Dissertations > Antioxidant Nutrients and Oxidative DNA Damage in Healthy African American and White Adults

Cancer is the leading cause of death for those under 85 years of age in the United States. All-cause cancer rates are higher for African Americans than other racial or ethnic groups; however, the reasons for this disproportionately high cancer burden are not well understood. Diets high in fruits and vegetables have been associated with lower risk of many cancers. One mechanism by which diet may reduce cancer risk is through consumption of antioxidant nutrients, which decrease the adverse effects of reactive oxygen species (ROS) on normal physiological functions. High ROS levels can lead to oxidative stress, in which the imbalance of radical-generating agent concentrations exceeds the body's defense mechanisms. Under conditions of elevated oxidative stress (e.g., low antioxidant intakes) defenses may be overwhelmed and excess oxidative stress can lead to oxidative damage of DNA causing significant base damage, strand breaks, and ultimately carcinogenesis. Using data from a generally healthy sample of African American and White adult participants in the DIet, Supplements, and Health (DISH) study (n=164, 51% African American), we examined potential racial differences in antioxidant (vitamin C, vitamin E, and carotenoids) intakes/blood concentrations and oxidative DNA damage; associations between plasma antioxidant concentrations and oxidative DNA damage; and demographic, behavioral, and psychosocial correlates of individual antioxidant concentrations and oxidative DNA damage. In addition, we determined psychosocial correlates of fruit and vegetable (antioxidant rich foods) intakes in African Americans in a cross-sectional study of African Americans ages 18 to 70 (n=658). This research fills important gaps in knowledge by contributing information about potential racial differences in 1) antioxidant intakes and blood concentrations, 2) oxidative stress levels, 3) associations between antioxidant concentrations and oxidative stress, 4) demographic, behavioral, and psychosocial factors that influence blood concentrations of antioxidants and oxidative DNA damage levels and also those of antioxidant-rich foods. The identification of modifiable factors (e.g., diet), mechanisms of carcinogenesis (e.g., oxidative DNA damage), and/or mediating factors that contribute to these factors (e.g., psychosocial factors) are critical for the design and implementation of cancer prevention and control programs to reduce the disparate cancer burden among African Americans.