Urinary concentrations of 2:16-hydroxyestrone (2:16-OHE1) approximate concentrations of 2-OHE1 and 16α -OHE1 in breast tissue. As estrogens are purported to be involved in breast cancer development, the 2:16-OHE1 ratio can provide an indication of estrogen metabolite exposure in the breast. With prior studies observing associations between urinary estrogen metabolites and dietary intake of fruits, vegetables, and fiber ascertained from food questionnaires, we examined associations between dietary factors ascertained through 3-day food records and urinary 2:16-OHE1 in 191 pre-menopausal healthy women. Fruit consumption was positively associated with 2:16-OHE1 after adjustment for total energy, ethnicity, body mass index, parity, smoking history, and serum estradiol (p= 0.003). Fruit consumption was positively associated with 2- OHE1 concentrations (p=0.006), but was not associated with 16α-OHE1 (p=0.92). The Musaceae botanical grouping (comprised primarily of bananas) was positively associated with the 2:16-OHE1 ratio, and Rosaceae (comprised of citrus fruits) and Musaceae botanical groupings were positively associated with 2-OHE1 (but not 16α-OHE1) concentrations, after adjustment for confounders. Our data suggest that dietary fruit intake is associated with urinary 2- OHE1 and the 2:16-OHE1 ratio and that breast tissue exposure to estrogen metabolites may thus be influenced by diet.
Keywords: botanical groupings; diet; estrogen metabolism.