Effect of energy deficiency on estrogen metabolism in premenopausal women

Kim C. Westerlind, Nancy I. Williams

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


PURPOSE: Physical activity has been associated with decreased breast cancer risk, potentially through changes in estrogen metabolism. Two-hydroxyestrone (2-OHE1) and 16α-hydroxyestrone (16α-OHE1) have different biological properties, and the ratio of these metabolites (2/16) has been proposed to predict breast cancer risk. Diet and exercise have been found to influence estrogen metabolism, particularly when a state of negative energy balance is achieved. We sought to determine whether 4 months of moderate-intensity exercise coupled with calorie restriction would result in changes in urinary 2-OHE1, 16α-OHE1, or 2/16 in sedentary, premenopausal, eumenorrheic women. METHODS: Average age was 31.5 yr, average body fat was 31.6%, and average BMI was 23.7. Urinary estrogen metabolites were measured in 24 women during the baseline and for four intervention months in the midfollicular and midluteal phases. RESULTS: The intervention produced a significant drop in body fat (4.5%) and body weight (3.7 kg). Aerobic fitness increased significantly (26%; P < 0.001). Overall, there were no significant effects of the diet and exercise intervention on 2-OHE1, 16α-OHE1, or 2/16. However, when divided into tertiles according to baseline 2/16, the intervention resulted in significant increases in 2/16 in women in the lowest tertile. Women in the lowest tertile (average 2/16 = 0.91) did not differ from the other tertiles in baseline estradiol concentrations, body fat, weight, fitness, or changes in these variables with the intervention. CONCLUSION: The data suggest that women at higher risk for developing breast cancer because of low 2/16 may reduce their risk by participating in lifestyle interventions such as exercise/calorie restriction.

Original languageEnglish (US)
Pages (from-to)1090-1097
Number of pages8
JournalMedicine and science in sports and exercise
Issue number7
StatePublished - Jul 2007

All Science Journal Classification (ASJC) codes

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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