Estrogen Metabolism

Phase 1 hepatic hydroxylation converts fat-soluble estrogens into three metabolites with different risk profiles via CYP1A1, CYP1B1, and CYP3A4. When COMT fails to methylate 4-hydroxyestrone, reactive quinones and semiquinones form, generating reactive oxygen species and DNA adducts that increase breast cancer risk. 8-OHdG is a urinary marker of oxidative DNA damage that can confirm quinone adduct formation but also reflects other causes including stress, insomnia, and chronic disease. Excessive beta-glucuronidase activity from the gut microbiome leads to deconjugation of estrogens and their return to enterohepatic circulation. DIM upregulates CYP1A1, increasing production of the safer 2-hydroxyestrone metabolite. COMT activity is reduced by insomnia, blood sugar dysregulation, psychosocial stress, oxidative stress, and excess sugar intake.