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

Objective: 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.

Methods: The participants were 513 employees, 20 to 65 y of age. Urinary levels of 8-hydroxydeoxyguanosine (8-OHdG) and 7-methylguanine (m 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 m Gua, with adjustment for potential confounders.

Results: 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, P = 0.40; ORAC, P = 0.27; TRAP, P = 0.45). Likewise, no association was found between overall dietary NEAC and m Gua levels (FRAP, P = 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 m Gua levels (P = 0.049).

Conclusion: Overall, dietary NEAC was not associated with 8-OHdG or m Gua levels. In contrast, dietary NEAC from foods but not beverages may be inversely associated with DNA damage caused by methylation.