Associations of antioxidant nutrients and oxidative DNA damage in healthy African-American and White adults.
High antioxidant intake has been shown to reduce cancer risk and may also mitigate the effects of oxidative DNA damage, which is hypothesized to be causally linked to carcinogenesis. This study examined potential racial differences in (a) dietary intakes and plasma concentrations of vitamin C, vitamin E, and carotenoids and oxidative DNA damage and (b) associations between plasma antioxidants and oxidative DNA damage. Data were from a cross-sectional study of 164 generally healthy nonsmoking African-Americans and Whites in North Carolina, ages 20 to 45 years, equally distributed by race and sex. Participants completed a demographic and health questionnaire, four 24-h dietary recalls, and a dietary supplement inventory; had height and weight measured; and provided a semifasting blood sample. African-Americans had statistically significantly lower plasma concentrations of vitamin E, alpha-carotene, beta-carotene, and lutein + zeaxanthin than Whites, as well as lower self-reported intake of most antioxidants. Levels of oxidative DNA damage, measured using the alkaline comet assay, were lower in African-Americans than Whites. An inverse association between lycopene and oxidative DNA damage (r = -0.20; P = 0.03) was found in the combined study population after adjusting for sex, age, body mass index, passive smoke exposure, physical activity, education, income, and alcohol intake. There was also a positive association of vitamin E with oxidative DNA damage in the total population (r = 0.21; P = 0.02) and in African-American men (r = 0.63; P = 0.01) after adjusting for covariates. This study is among the first to examine these associations in a sample of healthy adults with an adequate representation of African-Americans.