Background: The relationship between dietary antioxidants and breast cancer (BrCa) has been investigated in various studies. As a limitation, they generally investigate the relationship between one specific antioxidant and the risk/odds of BrCa, and synergistic or inhibitory effects are less considered. Dietary antioxidant index (DAI) is a reliable nutritional tool that evaluates total nutritional antioxidant capacity and is validated with serum total antioxidant capacity (TAC) and Malondialdehyde (MDA). Our study aimed to investigate the association between the DAI and the odds of BrCa and the correlation between the DAI and pathobiological markers. We hypnotized a correlation between DAI and pathobiological markers, and there is an association between DAI and the odds of BrCa.Methods: Our study included 145 incidence cases of BrCa and 148 hospital-based controls. Controls were randomly selected from patients attending the same center and were frequency-matched on age (±10 years). DAI was calculated based on a valid semi-quantitative 168-item food frequency questionnaire data. DAI standardizes intake of major dietary antioxidants, including vitamins A, E, C, selenium, zinc, and magnesium, and presents them as summarized scores.Results: Modeling with multivariable regressions adjusting for major confounders including age, education, body mass index, occupation, alcohol, smoking, pregnancy, history of cancer, menarche age, metabolic equivalent of task, hormone replacement therapy, and total energy intake, there was a significant association between odds of BrCa and DAI (odds ratio = 0.18; 95% confidence interval:0.09-0.37; p-value= <0.01). After multiple controls, there was a significant and weak reverse correlation between DAI and the number of lymph node(s) (correlation coefficient= -.140; p-value = 0.05).Conclusion: Our study supports the hypothesis that dietary antioxidants intake is associated with a reduced odds of BrCa. Evidently, DAI can reveal these relationships better than a single study of antioxidants. However, further studies are needed to confirm or refute these results.
Keywords: Malondialdehyde (MDA); Total antioxidant capacity (TAC); Vitamin A; Vitamin C; Vitamin E; Zinc; food frequency questionnaire (FFQ); nutritional assessment; selenium.