Dietary non-enzymatic antioxidant capacity and DNA damage in a working population.

Abstract

The aim of this study was to investigate the potential links between dietary non-enzymatic antioxidant capacity (NEAC) in overall diet and separately from foods and beverages and markers of DNA damage. The participants were 513 employees, 20 to 65y of age. Urinary levels of 8-hydroxydeoxyguanosine (8-OHdG) and 7-methylguanine (m7 Gua) were measured using column-switching high-performance liquid chromatography. Dietary NEAC was determined from databases of NEAC measurements obtained by different assays: ferric reducing-antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and total radical-trapping antioxidant parameter (TRAP). Dietary NEAC for each participant was calculated by multiplying the estimated NEAC values with the consumed amount and summing up those values, which was ascertained by a validated brief self-administered diet history questionnaire. Multiple-regression analyses were performed to assess the associations between dietary NEAC and 8-OHdG and m7 Gua, with adjustment for potential confounders. No statistically significant associations were found between overall dietary NEAC or NEAC from either foods or beverages and urinary 8-OHdG levels, after adjustment for potential confounders (overall: FRAP, Ptrend=0.40; ORAC, P=0.27; TRAP, P=0.45). Likewise, no association was found between overall dietary NEAC and m7 Gua levels (FRAP, Ptrend=0.30; ORAC, P=0.65; TRAP, P=0.41). However, we did identify significant inverse association between NEAC from foods, as estimated by TRAP, and m7 Gua levels (Ptrend=0.049). Overall, dietary NEAC was not associated with 8-OHdG or m7 Gua levels. In contrast, dietary NEAC from foods but not beverages may be inversely associated with DNA damage caused by methylation.