Our results supported and further elucidated the possible mechanism from different levels that BRCA1 restrains oxidative stress via repairing DNA double-strand breaks, highlighting a new perspective that a daily diet containing relatively high doses of flavonoids may be more conducive to tumor inhibition for breast cancer patients, especially for those with BRCA1 mutations or silence, thus leading to synthetic lethality, which could be more beneficial in prolonging prognosis. Here, BRCA1 is linked to breast cancer.