8572
document
The specific role of isoflavones on estrogen metabolism in premenopausal women . BACKGROUND There is increasing evidence that dietary factors may play a role in the production , metabolism , and bioavailability of sex hormones and their impact on target tissues . The specific objective of this study was to evaluate the effectiveness of supplementing a group of premenopausal women who were free of breast carcinoma with a dietary supplement of isoflavones ( 40 mg per day ) in producing a change in steroid hormones and menstrual cycle length . METHODS Sixty-eight consecutively recruited , premenopausal , omnivorous women of all races and ethnicities between the ages of 25 years and 55 years were admitted to the study and randomized to an experimental group supplemented with soy ( 40 mg genistein per day ) or to a control group that consumed a placebo for a 12-week period . Changes in their anthropometric , nutritional , and hormonal biomarkers from early follicular phase were analyzed at baseline and post-intervention . RESULTS Serum-free estradiol and estrone levels decreased moderately in the experimental group . Serum hormone-binding globulin levels increased in 41.4 % of women in the experimental group compared with 37.5 % of women in the placebo group . Free estradiol decreased in 53.85 % of women in the experimental group compared with 37.5 % of women in the placebo group . Estrone decreased in 55.56 % of women in the experimental group compared with 42.86 % in the placebo group . Those women in the experimental group who were consuming soy had their mean menstrual cycle length increased by 3.52 days compared with a mean decrease of 0.06 days for women in the placebo group ( P = 0.04 ) from baseline to the third menstrual cycle . In addition , women who were taking soy had their mean follicular phase increase by 1.46 days compared with a mean increase of 0.14 days for women who were taking the placebo ( P = 0.08 ) . CONCLUSIONS These data suggest that increased isoflavone intake affects estrogen metabolism by altering the steroid hormone concentrations and menstrual cycle length , thereby demonstrating a potential to reduce the risk for breast carcinoma .
8573
Intervention_Pharmacological
isoflavones
8574
Intervention_Pharmacological
isoflavones
8575
Intervention_Pharmacological
soy ( 40
8576
Intervention_Control
placebo
8577
Intervention_Control
placebo
8578
Intervention_Control
placebo
8579
Intervention_Control
placebo
8580
Intervention_Pharmacological
soy
8581
Intervention_Control
placebo
8582
Intervention_Pharmacological
soy
8583
Intervention_Control
placebo
8584
Intervention_Pharmacological
isoflavone
8585
Outcome_Physical
anthropometric
8586
Outcome_Physical
nutritional
8587
Outcome_Physical
hormonal biomarkers
8588
Outcome_Physical
Serum-free estradiol
8589
Outcome_Physical
estrone levels
8590
Outcome_Physical
Serum hormone-binding globulin levels
8591
Outcome_Physical
Free estradiol
8592
Outcome_Physical
mean menstrual cycle length
8593
Outcome_Physical
mean follicular phase increase
8594
Participant_Condition
in premenopausal
8595
Participant_Sex
women
8596
Participant_Condition
.
8597
Participant_Condition
carcinoma
8598
Participant_Sample-size
Sixty-eight
8599
Participant_Age
25 years
8600
Participant_Age
55 years