Objective: To investigate whether the dietary phytochemical, indole-3-carbinol (13C), influences the level of estradiol 2-hydroxylation in obese women.
Design: A clinical intervention study involving the ingestion of purified 13C, 400 mg, for two months.
Subjects: Five healthy, overweight, premenopausal women (age: 35-47 y, body mass index (BMI): 27-53 kg/m2).
Measurements: Two estrogen metabolites, 2-hydroxyestrone (2OHE1) and estriol (E3), were measured by radioimmunoassay in untimed overnight urine samples, before and after ingestion of 13C.
Results: The ratio of urinary estrogens, 2OHE1/E3, was significantly increased in obese women following 13C, reflecting induction of 2-hydroxylation in these women.
Conclusions: Obese premenopausal women experience increased estrogen 2-hydroxylation in response to the dietary agent, 13C, similar to non-obese women. This response to 13C may result in a hormonal milieu that helps reduce estrogen-dependent cancer risk.