Effect of Dietary Soy on Estrogens in Breast Fluid, Blood, and Urine Samples From Healthy Women

University of Hawaii Cancer Research Center

Status and phase: Completed; Phase 3

Conditions: Breast Cancer; Healthy, no Evidence of Disease

Treatments: Dietary Supplement: soy isoflavones

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT00513916

UHM-CHS-4116

CDR0000560821

Details and patient eligibility

About

RATIONALE: Chemoprevention is the use of certain drugs to keep cancer from forming. Eating a diet high in isoflavones, compounds found in soy foods, may keep cancer from forming.

PURPOSE: This randomized phase III trial is studying the effects of dietary soy on estrogens in breast fluid, blood, and urine samples from healthy women.

Full description

OBJECTIVES:

• Examine the effects of two daily servings of soy on estrogen levels in nipple aspirate fluid (NAF) and serum.
• Investigate cytologic patterns of epithelial breast cells obtained from NAF as a measure of proliferation in relation to soy intake.
• Explore the effect of two daily servings of soy on cytochrome alterations of estrogen metabolism as expressed in the formation of urinary 2-, 16α-, and 4-hydroxy estrogen metabolites.
• Compare estrogen levels in NAF and serum measured at the same time during the luteal phase.

OUTLINE: This is a multicenter study. Participants are randomized to 1 of 2 intervention arms.

• Arm I: Participants partake in a high soy diet consisting of 2 daily soy servings (approximately 50mg isoflavones). The choice of soy foods will include ½ cup of tofu, ¾ cup of soy milk, or ¼ cup of soy nuts. Replacement of currently consumed foods with soy foods will be encouraged.
• Arm II: Participants will be asked to keep their soy intake below 3 servings per week. The participants will also receive general nutrition counseling.

In both arms, intervention continues for 6 months. After 6 months, participants undergo a 1-month washout period and then cross-over to the other intervention arm.

Nipple aspirate fluid, urine, and blood samples are collected periodically to measure laboratory endpoints.

Enrollment: 100 estimated patients

Sex: Female

Ages: 30 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

DISEASE CHARACTERISTICS:

• Healthy participant

  • No diagnosis of cancer

PATIENT CHARACTERISTICS:

• Premenopausal
• Regular menstrual cycles

PRIOR CONCURRENT THERAPY:

• Not taking birth control pills or other hormones

Trial design

100 participants in 2 patient groups

Arm I

Experimental group

Description:

Participants partake in a high soy diet consisting of 2 daily soy servings (approximately 50mg isoflavones). The choice of soy foods will include ½ cup of tofu, ¾ cup of soy milk, or ¼ cup of soy nuts. Replacement of currently consumed foods with soy foods will be encouraged.

Treatment:

Dietary Supplement: soy isoflavones

Arm II

Active Comparator group

Description:

Participants will be asked to keep their soy intake below 3 servings per week. The participants will also receive general nutrition counseling.

Treatment:

Dietary Supplement: soy isoflavones