Antioxidant status and dietary lipid unsaturation modulate oxidative DNA damage.

High performance liquid chromatography with electrochemical detection (HPLC-EC) was used to measure 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker for oxidative DNA damage, in mammary gland isolated from tumor-bearing and tumor-free rats fed diets of varied fatty acid composition and vitamin E and selenium content. A method for tissue preparation and analysis is reported and a significant positive correlation shown between degree of unsaturation of dietary fatty acids and 8-OHdG concentration, regardless of antioxidant status. The increase in 8-OHdG concentration with greater fatty acid unsaturation was more pronounced in the absence of adequate dietary vitamin E and selenium. The implications of these data for defining the role of dietary lipid in the process of mammary carcinogenesis are discussed.